From a4603231ff331c1ded9cec17884b02258899f12b Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Tue, 24 Mar 2020 17:29:16 +0100
Subject: [PATCH 01/33] Adjusted serial version UIDs and Message#toString()

---
 src/main/java/envoy/data/Message.java | 6 ++++--
 src/main/java/envoy/data/User.java    | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/main/java/envoy/data/Message.java b/src/main/java/envoy/data/Message.java
index 7a8adc4..ab26c9a 100644
--- a/src/main/java/envoy/data/Message.java
+++ b/src/main/java/envoy/data/Message.java
@@ -57,7 +57,7 @@ public class Message implements Serializable {
 	private Date			receivedDate, readDate;
 	private MessageStatus	status;
 
-	private static final long serialVersionUID = -4393477412979594435L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Initializes a {@link Message} with values for all of its properties. The use
@@ -107,13 +107,15 @@ public class Message implements Serializable {
 
 	@Override
 	public String toString() {
-		return String.format("TextMessage[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,hasAttachment=%b]",
+		return String.format(
+				"TextMessage[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,forwarded,hasAttachment=%b]",
 				id,
 				senderId,
 				recipientId,
 				new SimpleDateFormat("dd.MM.yyyy HH:mm:ss").format(creationDate),
 				status,
 				text,
+				forwarded,
 				attachment != null);
 	}
 
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index 25be9e8..bf20fdf 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -49,7 +49,7 @@ public class User implements Serializable {
 
 	private UserStatus status;
 
-	private static final long serialVersionUID = 3530947374856708236L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Initializes a {@link User}. The {@link UserStatus} is set to

From 3b24d46886a5cb4946636791b27a2013d8d4db9b Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Tue, 24 Mar 2020 19:06:56 +0100
Subject: [PATCH 02/33] Added groups

additionally added:
* serialVersionUID is now equal to 0L
* Renamed classes with a two-letter initialism according to convention
---
 .settings/org.eclipse.jdt.ui.prefs            |   3 +
 src/main/java/envoy/data/Contact.java         |  58 +++++++++
 src/main/java/envoy/data/Group.java           |  68 ++++++++++
 .../{IdGenerator.java => IDGenerator.java}    |  12 +-
 .../java/envoy/data/MessageAttachment.java    |   2 +-
 src/main/java/envoy/data/MessageBuilder.java  |  10 +-
 src/main/java/envoy/data/User.java            |  34 ++---
 .../envoy/event/ContactOperationEvent.java    | 122 +++++++++---------
 .../envoy/event/ContactSearchRequest.java     |  48 +++----
 .../java/envoy/event/ContactSearchResult.java |   2 +-
 src/main/java/envoy/event/Event.java          |   4 +-
 .../envoy/event/HandshakeRejectionEvent.java  |   2 +-
 ...orRequest.java => IDGeneratorRequest.java} |   6 +-
 .../envoy/event/MessageStatusChangeEvent.java |   6 +-
 .../envoy/event/UserStatusChangeEvent.java    |   2 +-
 15 files changed, 245 insertions(+), 134 deletions(-)
 create mode 100644 .settings/org.eclipse.jdt.ui.prefs
 create mode 100644 src/main/java/envoy/data/Contact.java
 create mode 100644 src/main/java/envoy/data/Group.java
 rename src/main/java/envoy/data/{IdGenerator.java => IDGenerator.java} (73%)
 rename src/main/java/envoy/event/{IdGeneratorRequest.java => IDGeneratorRequest.java} (66%)

diff --git a/.settings/org.eclipse.jdt.ui.prefs b/.settings/org.eclipse.jdt.ui.prefs
new file mode 100644
index 0000000..f2ac36a
--- /dev/null
+++ b/.settings/org.eclipse.jdt.ui.prefs
@@ -0,0 +1,3 @@
+eclipse.preferences.version=1
+org.eclipse.jdt.ui.javadoc=true
+org.eclipse.jdt.ui.text.custom_code_templates=<?xml version\="1.0" encoding\="UTF-8" standalone\="no"?><templates><template autoinsert\="false" context\="gettercomment_context" deleted\="false" description\="Comment for getter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.gettercomment" name\="gettercomment">/**\n * @return the ${bare_field_name}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="settercomment_context" deleted\="false" description\="Comment for setter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.settercomment" name\="settercomment">/**\n * @param ${param} the ${bare_field_name} to set\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="constructorcomment_context" deleted\="false" description\="Comment for created constructors" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorcomment" name\="constructorcomment">/**\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="filecomment_context" deleted\="false" description\="Comment for created Java files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.filecomment" name\="filecomment"/><template autoinsert\="false" context\="typecomment_context" deleted\="false" description\="Comment for created types" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.typecomment" name\="typecomment">/**\n * Project\: &lt;strong&gt;${project_name}&lt;/strong&gt;&lt;br&gt;\n * File\: &lt;strong&gt;${file_name}&lt;/strong&gt;&lt;br&gt;\n * Created\: &lt;strong&gt;${date}&lt;/strong&gt;&lt;br&gt;\n * \n * @author ${user}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="fieldcomment_context" deleted\="false" description\="Comment for fields" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.fieldcomment" name\="fieldcomment"/><template autoinsert\="false" context\="methodcomment_context" deleted\="false" description\="Comment for non-overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodcomment" name\="methodcomment">/**\n * ${tags}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="modulecomment_context" deleted\="false" description\="Comment for modules" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.modulecomment" name\="modulecomment">/**\n * @author ${user}\n *\n * ${tags}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="overridecomment_context" deleted\="false" description\="Comment for overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.overridecomment" name\="overridecomment">/**\n * {@inheritDoc}\n */</template><template autoinsert\="false" context\="delegatecomment_context" deleted\="false" description\="Comment for delegate methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.delegatecomment" name\="delegatecomment">/**\n * ${tags}\n * ${see_to_target}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="true" context\="newtype_context" deleted\="false" description\="Newly created files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.newtype" name\="newtype">${filecomment}\n${package_declaration}\n\n${typecomment}\n${type_declaration}</template><template autoinsert\="true" context\="classbody_context" deleted\="false" description\="Code in new class type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.classbody" name\="classbody">\n</template><template autoinsert\="true" context\="interfacebody_context" deleted\="false" description\="Code in new interface type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.interfacebody" name\="interfacebody">\n</template><template autoinsert\="true" context\="enumbody_context" deleted\="false" description\="Code in new enum type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.enumbody" name\="enumbody">\n</template><template autoinsert\="true" context\="annotationbody_context" deleted\="false" description\="Code in new annotation type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.annotationbody" name\="annotationbody">\n</template><template autoinsert\="false" context\="catchblock_context" deleted\="false" description\="Code in new catch blocks" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.catchblock" name\="catchblock">${exception_var}.printStackTrace();</template><template autoinsert\="false" context\="methodbody_context" deleted\="false" description\="Code in created method stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodbody" name\="methodbody">${body_statement}</template><template autoinsert\="false" context\="constructorbody_context" deleted\="false" description\="Code in created constructor stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorbody" name\="constructorbody">${body_statement}</template><template autoinsert\="true" context\="getterbody_context" deleted\="false" description\="Code in created getters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.getterbody" name\="getterbody">return ${field};</template><template autoinsert\="true" context\="setterbody_context" deleted\="false" description\="Code in created setters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.setterbody" name\="setterbody">${field} \= ${param};</template></templates>
diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
new file mode 100644
index 0000000..3e830f1
--- /dev/null
+++ b/src/main/java/envoy/data/Contact.java
@@ -0,0 +1,58 @@
+package envoy.data;
+
+import java.io.Serializable;
+
+/**
+ * This class is the superclass for both {@link User} and {@link Group}.<br>
+ * It provides an id and a name for each user and group.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>Contact.java</strong><br>
+ * Created: <strong>24 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy v0.1-beta
+ */
+public abstract class Contact implements Serializable {
+
+	private long	id;
+	private String	name;
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Creates a new instance of a {@link Contact}.
+	 *
+	 * @param id   the id of this contact
+	 * @param name the name of this contact
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Contact(long id, String name) {
+		this.id		= id;
+		this.name	= name;
+	}
+
+	/**
+	 * @return the ID of this {@link Contact}
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public long getId() { return id; }
+
+	/**
+	 * @return the name of this {@link Contact}
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public String getName() { return name; }
+
+	/**
+	 * @param newName the new name of this {@link Contact}
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void setName(String newName) { name = newName; }
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String toString() { return String.format("Contact[id=%d,name=%s]", id, name); }
+}
diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
new file mode 100644
index 0000000..7de0f20
--- /dev/null
+++ b/src/main/java/envoy/data/Group.java
@@ -0,0 +1,68 @@
+package envoy.data;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>Group.java</strong><br>
+ * Created: <strong>24 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public class Group extends Contact {
+
+	private static final long serialVersionUID = 0L;
+
+	// TODO add admins
+	private List<Long> memberIDs = new ArrayList<>();
+
+	/**
+	 * Creates a new instance of a {@link Group}.
+	 *
+	 * @param id   the id of this group
+	 * @param name the name of this group
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Group(long id, String name) { super(id, name); }
+
+	/**
+	 * Creates a new instance of a {@link Group}.
+	 *
+	 * @param id        the id of this group
+	 * @param name      the name of this group
+	 * @param memberIDs the IDs of all members that should be preinitialized
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Group(long id, String name, List<Long> memberIDs) {
+		super(id, name);
+		this.memberIDs = memberIDs;
+	}
+
+	/**
+	 * @return the IDs of all members of this group
+	 * @since Envoy Common v0.1-beta
+	 */
+	public List<Long> getMemberIDs() { return memberIDs; }
+
+	/**
+	 * @param memberIDs the member IDs to set
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void setMemberIDs(List<Long> memberIDs) { this.memberIDs = memberIDs; }
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String toString() {
+		StringBuilder sb = new StringBuilder();
+		sb.append("Group[id=" + getId() + ",name=" + getName() + ",memberIDs=[");
+		memberIDs.forEach(id -> { sb.append(id); sb.append(", "); });
+		// deleting the final ", "
+		sb.delete(sb.length() - 2, sb.length());
+		sb.append("]]");
+		return sb.toString();
+	}
+}
diff --git a/src/main/java/envoy/data/IdGenerator.java b/src/main/java/envoy/data/IDGenerator.java
similarity index 73%
rename from src/main/java/envoy/data/IdGenerator.java
rename to src/main/java/envoy/data/IDGenerator.java
index 26b7131..91681e0 100644
--- a/src/main/java/envoy/data/IdGenerator.java
+++ b/src/main/java/envoy/data/IDGenerator.java
@@ -6,33 +6,33 @@ import java.io.Serializable;
  * Generates increasing IDs between two numbers.<br>
  * <br>
  * Project: <strong>envoy-common</strong><br>
- * File: <strong>IdGenerator.java</strong><br>
+ * File: <strong>IDGenerator.java</strong><br>
  * Created: <strong>31.12.2019</strong><br>
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class IdGenerator implements Serializable {
+public class IDGenerator implements Serializable {
 
 	private final long	end;
 	private long		current;
 
-	private static final long serialVersionUID = -1517378307055845147L;
+	private static final long serialVersionUID = 0L;
 
 	/**
-	 * Creates an instance of {@link IdGenerator}.
+	 * Creates an instance of {@link IDGenerator}.
 	 *
 	 * @param begin the first ID
 	 * @param size  the amount of IDs to provide
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public IdGenerator(long begin, long size) {
+	public IDGenerator(long begin, long size) {
 		current	= begin;
 		end		= begin + size;
 	}
 
 	@Override
-	public String toString() { return String.format("IdGenerator[current=%d,end=%d]", current, end); }
+	public String toString() { return String.format("IDGenerator[current=%d,end=%d]", current, end); }
 
 	/**
 	 * @return {@code true} if there are unused IDs remaining
diff --git a/src/main/java/envoy/data/MessageAttachment.java b/src/main/java/envoy/data/MessageAttachment.java
index 23a2c2e..3d04eab 100644
--- a/src/main/java/envoy/data/MessageAttachment.java
+++ b/src/main/java/envoy/data/MessageAttachment.java
@@ -19,7 +19,7 @@ import envoy.util.SerializationUtils;
  */
 public class MessageAttachment<T> implements Serializable {
 
-	private static final long	serialVersionUID	= 262683855157198013L;
+	private static final long	serialVersionUID	= 0L;
 	private T					value;
 
 	/**
diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index 9129357..3ee6ec5 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -33,11 +33,11 @@ public class MessageBuilder {
 	 *
 	 * @param senderId    the ID of the user who sends the {@link Message}
 	 * @param recipientId the ID of the user who receives the {@link Message}
-	 * @param idGenerator the ID generator used to generate a unique {@link Message}
+	 * @param iDGenerator the ID generator used to generate a unique {@link Message}
 	 *                    id
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public MessageBuilder(long senderId, long recipientId, IdGenerator idGenerator) { this(senderId, recipientId, idGenerator.next()); }
+	public MessageBuilder(long senderId, long recipientId, IDGenerator iDGenerator) { this(senderId, recipientId, iDGenerator.next()); }
 
 	/**
 	 * Creates an instance of {@link MessageBuilder} with all mandatory values
@@ -61,12 +61,12 @@ public class MessageBuilder {
 	 *
 	 * @param msg         the message to copy
 	 * @param recipientId the ID of the user who receives the {@link Message}
-	 * @param idGenerator the ID generator used to generate a unique {@link Message}
+	 * @param iDGenerator the ID generator used to generate a unique {@link Message}
 	 *                    id
 	 * @since Envoy v0.1-beta
 	 */
-	public MessageBuilder(Message msg, long recipientId, IdGenerator idGenerator) {
-		this(msg.getRecipientId(), recipientId, idGenerator.next());
+	public MessageBuilder(Message msg, long recipientId, IDGenerator iDGenerator) {
+		this(msg.getRecipientId(), recipientId, iDGenerator.next());
 		this.attachment		= msg.getAttachment();
 		this.creationDate	= new Date();
 		this.forwarded		= true;
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index bf20fdf..be3881e 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -1,7 +1,5 @@
 package envoy.data;
 
-import java.io.Serializable;
-
 /**
  * Represents a unique user with a unique, numeric ID, a name and a current
  * {@link UserStatus}.<br>
@@ -13,7 +11,7 @@ import java.io.Serializable;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class User implements Serializable {
+public class User extends Contact {
 
 	/**
 	 * This enumeration defines all possible statuses a user can have.
@@ -44,25 +42,21 @@ public class User implements Serializable {
 		OFFLINE;
 	}
 
-	private final long		id;
-	private final String	name;
-
 	private UserStatus status;
 
-	private static final long serialVersionUID = 0L;
+	private static final long serialVersionUID = 1L;
 
 	/**
-	 * Initializes a {@link User}. The {@link UserStatus} is set to
-	 * {@link UserStatus#ONLINE}.
+	 * Initializes a {@link User}. <br>
+	 * The {@link UserStatus} is set to {@link UserStatus#ONLINE}.
 	 *
 	 * @param id   unique ID
 	 * @param name user name
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public User(long id, String name) {
-		this.id		= id;
-		this.name	= name;
-		status		= UserStatus.ONLINE;
+		super(id, name);
+		status = UserStatus.ONLINE;
 	}
 
 	/**
@@ -74,24 +68,12 @@ public class User implements Serializable {
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public User(long id, String name, UserStatus status) {
-		this(id, name);
+		super(id, name);
 		this.status = status;
 	}
 
 	@Override
-	public String toString() { return String.format("User[id=%d,name=%s,status=%s]", id, name, status); }
-
-	/**
-	 * @return the ID of this {@link User}
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public long getId() { return id; }
-
-	/**
-	 * @return the name of this {@link User}
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public String getName() { return name; }
+	public String toString() { return String.format("User[id=%d,name=%s,status=%s]", getId(), getName(), status); }
 
 	/**
 	 * @return the current status of this user
diff --git a/src/main/java/envoy/event/ContactOperationEvent.java b/src/main/java/envoy/event/ContactOperationEvent.java
index 7410e65..9fe505d 100644
--- a/src/main/java/envoy/event/ContactOperationEvent.java
+++ b/src/main/java/envoy/event/ContactOperationEvent.java
@@ -1,61 +1,61 @@
-package envoy.event;
-
-import envoy.data.User;
-
-/**
- * Signifies the modification of a contact list.<br>
- * <br>
- * Project: <strong>envoy-common</strong><br>
- * File: <strong>ContactOperationEvent.java</strong><br>
- * Created: <strong>05.02.2020</strong><br>
- *
- * @author Maximilian K&auml;fer
- * @since Envoy Common v0.2-alpha
- */
-public class ContactOperationEvent extends Event<User> {
-
-	/**
-	 * Specifies the operation performed on a contact list.<br>
-	 * <br>
-	 * Project: <strong>envoy-common</strong><br>
-	 * File: <strong>ContactOperationEvent.java</strong><br>
-	 * Created: <strong>05.02.2020</strong><br>
-	 *
-	 * @author Maximilian K&auml;fer
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public enum Operation {
-
-		/**
-		 * Adds a user to the contact list.
-		 */
-		ADD,
-
-		/**
-		 * Removes a user from the contact list.
-		 */
-		REMOVE;
-	}
-
-	private final Operation operationType;
-
-	private static final long serialVersionUID = -1166652868189511553L;
-
-	/**
-	 * Initializes a {@link ContactOperationEvent}.
-	 *
-	 * @param contact       the user on which the operation is performed
-	 * @param operationType the type of operation to perform
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public ContactOperationEvent(User contact, Operation operationType) {
-		super(contact);
-		this.operationType = operationType;
-	}
-
-	/**
-	 * @return the type of operation to perform
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public Operation getOperationType() { return operationType; }
-}
+package envoy.event;
+
+import envoy.data.User;
+
+/**
+ * Signifies the modification of a contact list.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>ContactOperationEvent.java</strong><br>
+ * Created: <strong>05.02.2020</strong><br>
+ *
+ * @author Maximilian K&auml;fer
+ * @since Envoy Common v0.2-alpha
+ */
+public class ContactOperationEvent extends Event<User> {
+
+	/**
+	 * Specifies the operation performed on a contact list.<br>
+	 * <br>
+	 * Project: <strong>envoy-common</strong><br>
+	 * File: <strong>ContactOperationEvent.java</strong><br>
+	 * Created: <strong>05.02.2020</strong><br>
+	 *
+	 * @author Maximilian K&auml;fer
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public enum Operation {
+
+		/**
+		 * Adds a user to the contact list.
+		 */
+		ADD,
+
+		/**
+		 * Removes a user from the contact list.
+		 */
+		REMOVE;
+	}
+
+	private final Operation operationType;
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Initializes a {@link ContactOperationEvent}.
+	 *
+	 * @param contact       the user on which the operation is performed
+	 * @param operationType the type of operation to perform
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public ContactOperationEvent(User contact, Operation operationType) {
+		super(contact);
+		this.operationType = operationType;
+	}
+
+	/**
+	 * @return the type of operation to perform
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public Operation getOperationType() { return operationType; }
+}
diff --git a/src/main/java/envoy/event/ContactSearchRequest.java b/src/main/java/envoy/event/ContactSearchRequest.java
index 4076265..bd13812 100644
--- a/src/main/java/envoy/event/ContactSearchRequest.java
+++ b/src/main/java/envoy/event/ContactSearchRequest.java
@@ -1,24 +1,24 @@
-package envoy.event;
-
-/**
- * Requests a contact search from the server.<br>
- * <br>
- * Project: <strong>envoy-common</strong><br>
- * File: <strong>ContactSearchRequest.java</strong><br>
- * Created: <strong>05.02.2020</strong><br>
- *
- * @author Maximilian K&auml;fer
- * @since Envoy Common v0.2-alpha
- */
-public class ContactSearchRequest extends Event<String> {
-
-	private static final long serialVersionUID = -7969312055630533627L;
-
-	/**
-	 * Initializes a {@link ContactSearchRequest}.
-	 *
-	 * @param searchPhrase the search phrase to use in the contact search
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public ContactSearchRequest(String searchPhrase) { super(searchPhrase); }
-}
+package envoy.event;
+
+/**
+ * Requests a contact search from the server.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>ContactSearchRequest.java</strong><br>
+ * Created: <strong>05.02.2020</strong><br>
+ *
+ * @author Maximilian K&auml;fer
+ * @since Envoy Common v0.2-alpha
+ */
+public class ContactSearchRequest extends Event<String> {
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Initializes a {@link ContactSearchRequest}.
+	 *
+	 * @param searchPhrase the search phrase to use in the contact search
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public ContactSearchRequest(String searchPhrase) { super(searchPhrase); }
+}
diff --git a/src/main/java/envoy/event/ContactSearchResult.java b/src/main/java/envoy/event/ContactSearchResult.java
index 929ee30..5f1691e 100644
--- a/src/main/java/envoy/event/ContactSearchResult.java
+++ b/src/main/java/envoy/event/ContactSearchResult.java
@@ -16,7 +16,7 @@ import envoy.data.User;
  */
 public class ContactSearchResult extends Event<List<User>> {
 
-	private static final long serialVersionUID = -8934154116102031561L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Creates an instance of {@link ContactSearchResult}.
diff --git a/src/main/java/envoy/event/Event.java b/src/main/java/envoy/event/Event.java
index 5b13306..809c5ec 100644
--- a/src/main/java/envoy/event/Event.java
+++ b/src/main/java/envoy/event/Event.java
@@ -15,7 +15,7 @@ public abstract class Event<T> implements Serializable {
 
 	protected final T value;
 
-	private static final long serialVersionUID = 4673659457380399167L;
+	private static final long serialVersionUID = 0L;
 
 	protected Event(T value) { this.value = value; }
 
@@ -39,7 +39,7 @@ public abstract class Event<T> implements Serializable {
 	 */
 	public static abstract class Valueless extends Event<Void> {
 
-		private static final long serialVersionUID = -9019362144094097997L;
+		private static final long serialVersionUID = 0L;
 
 		protected Valueless() { super(null); }
 
diff --git a/src/main/java/envoy/event/HandshakeRejectionEvent.java b/src/main/java/envoy/event/HandshakeRejectionEvent.java
index c89405d..b6efb38 100644
--- a/src/main/java/envoy/event/HandshakeRejectionEvent.java
+++ b/src/main/java/envoy/event/HandshakeRejectionEvent.java
@@ -44,7 +44,7 @@ public class HandshakeRejectionEvent extends Event<String> {
 	 */
 	public static final String UNKNOWN_REASON = "cause of failure is unknown";
 
-	private static final long serialVersionUID = -8723270093452609197L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Creates an instance of {@link HandshakeRejectionEvent} with an empty reason.
diff --git a/src/main/java/envoy/event/IdGeneratorRequest.java b/src/main/java/envoy/event/IDGeneratorRequest.java
similarity index 66%
rename from src/main/java/envoy/event/IdGeneratorRequest.java
rename to src/main/java/envoy/event/IDGeneratorRequest.java
index fe7871d..2994c75 100644
--- a/src/main/java/envoy/event/IdGeneratorRequest.java
+++ b/src/main/java/envoy/event/IDGeneratorRequest.java
@@ -2,16 +2,16 @@ package envoy.event;
 
 /**
  * Signifies to the server that the client needs a new
- * {@link envoy.data.IdGenerator} instance.<br>
+ * {@link envoy.data.IDGenerator} instance.<br>
  * <br>
  * Project: <strong>envoy-common</strong><br>
- * File: <strong>IdGeneratorRequest.java</strong><br>
+ * File: <strong>IDGeneratorRequest.java</strong><br>
  * Created: <strong>28 Jan 2020</strong><br>
  *
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.3-alpha
  */
-public class IdGeneratorRequest extends Event.Valueless {
+public class IDGeneratorRequest extends Event.Valueless {
 
 	private static final long serialVersionUID = 1431107413883364583L;
 }
diff --git a/src/main/java/envoy/event/MessageStatusChangeEvent.java b/src/main/java/envoy/event/MessageStatusChangeEvent.java
index d7e7e4a..0307e6e 100644
--- a/src/main/java/envoy/event/MessageStatusChangeEvent.java
+++ b/src/main/java/envoy/event/MessageStatusChangeEvent.java
@@ -14,10 +14,10 @@ import envoy.data.Message;
  */
 public class MessageStatusChangeEvent extends Event<Message.MessageStatus> {
 
-	private final long					id;
-	private final Date					date;
+	private final long	id;
+	private final Date	date;
 
-	private static final long serialVersionUID = 4566145392192761313L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Initializes a {@link MessageStatusChangeEvent}.
diff --git a/src/main/java/envoy/event/UserStatusChangeEvent.java b/src/main/java/envoy/event/UserStatusChangeEvent.java
index ed6e79f..8349653 100644
--- a/src/main/java/envoy/event/UserStatusChangeEvent.java
+++ b/src/main/java/envoy/event/UserStatusChangeEvent.java
@@ -15,7 +15,7 @@ public class UserStatusChangeEvent extends Event<UserStatus> {
 
 	private final long id;
 
-	private static final long serialVersionUID = 4566145392192761313L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Initializes a {@link UserStatusChangeEvent}.

From a89c93b428ce2a8c76504c6befd7cd89d4c299e2 Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Tue, 24 Mar 2020 21:11:16 +0100
Subject: [PATCH 03/33] Revised toString method in Group and changed id to
 final in Contact

---
 src/main/java/envoy/data/Contact.java |  2 +-
 src/main/java/envoy/data/Group.java   | 13 ++++++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index 3e830f1..96b703e 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -15,7 +15,7 @@ import java.io.Serializable;
  */
 public abstract class Contact implements Serializable {
 
-	private long	id;
+	private final long	id;
 	private String	name;
 
 	private static final long serialVersionUID = 0L;
diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index 7de0f20..cab866f 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -2,6 +2,7 @@ package envoy.data;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.StringJoiner;
 
 /**
  * Project: <strong>envoy-common</strong><br>
@@ -57,12 +58,10 @@ public class Group extends Contact {
 	 */
 	@Override
 	public String toString() {
-		StringBuilder sb = new StringBuilder();
-		sb.append("Group[id=" + getId() + ",name=" + getName() + ",memberIDs=[");
-		memberIDs.forEach(id -> { sb.append(id); sb.append(", "); });
-		// deleting the final ", "
-		sb.delete(sb.length() - 2, sb.length());
-		sb.append("]]");
-		return sb.toString();
+		var joiner = new StringJoiner(",", "Group[id=", "]");
+		joiner.add("id=" + getId());
+		joiner.add("name=" + getName());
+		joiner.add("memberIDs=" + getMemberIDs());
+		return joiner.toString();
 	}
 }

From e89a1bc2df72101ac0f6090503c342d9ced5aedf Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Tue, 24 Mar 2020 21:57:59 +0100
Subject: [PATCH 04/33] Revised Code Style

---
 src/main/java/envoy/data/Group.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index cab866f..4c662cc 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -17,7 +17,7 @@ public class Group extends Contact {
 	private static final long serialVersionUID = 0L;
 
 	// TODO add admins
-	private List<Long> memberIDs = new ArrayList<>();
+	private List<Long> memberIDs;
 
 	/**
 	 * Creates a new instance of a {@link Group}.
@@ -26,7 +26,7 @@ public class Group extends Contact {
 	 * @param name the name of this group
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Group(long id, String name) { super(id, name); }
+	public Group(long id, String name) { this(id, name, new ArrayList<>()); }
 
 	/**
 	 * Creates a new instance of a {@link Group}.

From eb7a8778de2ab30c705f95c8462a9b8acad6e2d7 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 25 Mar 2020 16:33:06 +0100
Subject: [PATCH 05/33] added GroupResizeEvent and NameChangeEvent

additionally refactored `getId()` method of Contact to `getID()`
---
 src/main/java/envoy/data/Contact.java         |  2 +-
 src/main/java/envoy/data/Group.java           |  2 +-
 src/main/java/envoy/data/User.java            |  2 +-
 .../java/envoy/event/GroupResizeEvent.java    | 86 +++++++++++++++++++
 .../java/envoy/event/NameChangeEvent.java     | 52 +++++++++++
 .../envoy/event/UserStatusChangeEvent.java    |  2 +-
 6 files changed, 142 insertions(+), 4 deletions(-)
 create mode 100644 src/main/java/envoy/event/GroupResizeEvent.java
 create mode 100644 src/main/java/envoy/event/NameChangeEvent.java

diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index 96b703e..e7a22ed 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -36,7 +36,7 @@ public abstract class Contact implements Serializable {
 	 * @return the ID of this {@link Contact}
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getId() { return id; }
+	public long getID() { return id; }
 
 	/**
 	 * @return the name of this {@link Contact}
diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index 4c662cc..44f91d4 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -59,7 +59,7 @@ public class Group extends Contact {
 	@Override
 	public String toString() {
 		var joiner = new StringJoiner(",", "Group[id=", "]");
-		joiner.add("id=" + getId());
+		joiner.add("id=" + getID());
 		joiner.add("name=" + getName());
 		joiner.add("memberIDs=" + getMemberIDs());
 		return joiner.toString();
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index be3881e..d282e29 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -73,7 +73,7 @@ public class User extends Contact {
 	}
 
 	@Override
-	public String toString() { return String.format("User[id=%d,name=%s,status=%s]", getId(), getName(), status); }
+	public String toString() { return String.format("User[id=%d,name=%s,status=%s]", getID(), getName(), status); }
 
 	/**
 	 * @return the current status of this user
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
new file mode 100644
index 0000000..1b6d153
--- /dev/null
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -0,0 +1,86 @@
+package envoy.event;
+
+import envoy.data.Contact;
+import envoy.data.Group;
+import envoy.data.User;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>GroupResizeEvent.java</strong><br>
+ * Created: <strong>25 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public class GroupResizeEvent extends Event<Long> {
+
+	private final long		groupID;
+	private OperationType	operationType;
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Project: <strong>envoy-common</strong><br>
+	 * File: <strong>GroupResizeEvent.java</strong><br>
+	 * Created: <strong>25 Mar 2020</strong><br>
+	 *
+	 * @author Leon Hofmeister
+	 * @since Envoy Common v0.1-beta
+	 */
+	public enum OperationType {
+		/**
+		 *
+		 */
+		ADD,
+		/**
+		 *
+		 */
+		REMOVE
+	}
+
+	/**
+	 * Initializes a {@link GroupResizeEvent} through a Contact where the name has
+	 * already been set.
+	 *
+	 * @param user          the {@link User} who wants to join or leave a group
+	 * @param group         the {@link Group} he wants to join or leave
+	 * @param operationType whether the user should be removed from this group. If
+	 *                      false,
+	 *                      this user will be added
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public GroupResizeEvent(User user, Group group, OperationType operationType) {
+		super(user.getID());
+		if (group.getMemberIDs().contains(user.getID())) {
+			if (operationType.equals(OperationType.ADD)) throw new IllegalStateException(
+					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");
+		} else if (operationType.equals(OperationType.REMOVE))
+			throw new IllegalStateException("Cannot remove " + user + " from group " + group.getID() + " because he is no part of this group");
+		groupID				= group.getID();
+		this.operationType	= operationType;
+	}
+
+	/**
+	 * @return the ID of the {@link Contact} this event is related to
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public long getGroupId() { return groupID; }
+
+	/**
+	 * @return the operationType
+	 * @since Envoy Common v0.1-beta
+	 */
+	public OperationType getOperationType() { return operationType; }
+
+	/**
+	 * @param operationType the operationType to set
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void setOperationType(OperationType operationType) { this.operationType = operationType; }
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operationType=%b]", get(), groupID, operationType); }
+}
\ No newline at end of file
diff --git a/src/main/java/envoy/event/NameChangeEvent.java b/src/main/java/envoy/event/NameChangeEvent.java
new file mode 100644
index 0000000..4cfa640
--- /dev/null
+++ b/src/main/java/envoy/event/NameChangeEvent.java
@@ -0,0 +1,52 @@
+package envoy.event;
+
+import envoy.data.Contact;
+
+/**
+ * This event informs<br>
+ * a) the server of the name change of a user or a group.
+ * b) another user of this users name change.
+ *
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>NameChangeEvent.java</strong><br>
+ * Created: <strong>25 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public class NameChangeEvent extends Event<String> {
+
+	private static final long	serialVersionUID	= 0L;
+	private final long			id;
+
+	/**
+	 * Creates a new {@link NameChangeEvent} for a user or a group.
+	 *
+	 * @param contactID the id of the {@link Contact} who wishes to change his name
+	 * @param newName   the new name of this contact
+	 * @since Envoy Common v0.1-beta
+	 */
+	public NameChangeEvent(long contactID, String newName) {
+		super(newName);
+		id = contactID;
+	}
+
+	/**
+	 * Initializes a {@link NameChangeEvent} through a Contact where the name has
+	 * already been set.
+	 *
+	 * @param contact the contact whose name was updated
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public NameChangeEvent(Contact contact) { this(contact.getID(), contact.getName()); }
+
+	/**
+	 * @return the ID of the {@link Contact} this event is related to
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public long getId() { return id; }
+
+	@Override
+	public String toString() { return String.format("NameChangeEvent[id=%d,name=%s]", id, value); }
+
+}
diff --git a/src/main/java/envoy/event/UserStatusChangeEvent.java b/src/main/java/envoy/event/UserStatusChangeEvent.java
index 8349653..8ab198c 100644
--- a/src/main/java/envoy/event/UserStatusChangeEvent.java
+++ b/src/main/java/envoy/event/UserStatusChangeEvent.java
@@ -36,7 +36,7 @@ public class UserStatusChangeEvent extends Event<UserStatus> {
 	 * @param user the User from which to build the event
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public UserStatusChangeEvent(User user) { this(user.getId(), user.getStatus()); }
+	public UserStatusChangeEvent(User user) { this(user.getID(), user.getStatus()); }
 
 	/**
 	 * @return the ID of the {@link User} this event is related to

From 4a3ee2002921d0fd4a0fb866235ce86d519b28ea Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 25 Mar 2020 16:55:34 +0100
Subject: [PATCH 06/33] Added GroupCreationEvent

---
 .../java/envoy/event/GroupCreationEvent.java  | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 src/main/java/envoy/event/GroupCreationEvent.java

diff --git a/src/main/java/envoy/event/GroupCreationEvent.java b/src/main/java/envoy/event/GroupCreationEvent.java
new file mode 100644
index 0000000..a2d393c
--- /dev/null
+++ b/src/main/java/envoy/event/GroupCreationEvent.java
@@ -0,0 +1,23 @@
+package envoy.event;
+
+/**
+ * This event creates a group with the given name.
+ *
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>GroupCreationEvent.java</strong><br>
+ * Created: <strong>25 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public class GroupCreationEvent extends Event<String> {
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * @param value the name of this group at creation time
+	 * @since Envoy Common v0.1-beta
+	 */
+	public GroupCreationEvent(String value) { super(value); }
+
+}

From 35aa316199552870f5087102f9f2617c3b11f85f Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 25 Mar 2020 17:12:55 +0100
Subject: [PATCH 07/33] Fixed Javadoc in GroupResizeEvent

---
 src/main/java/envoy/event/GroupResizeEvent.java | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index 1b6d153..e898752 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -5,6 +5,10 @@ import envoy.data.Group;
 import envoy.data.User;
 
 /**
+ * This event is used to communicate changes in the group size between client
+ * and server.<br>
+ * Possible actions are adding or removing certain {@link User}s to or from a certain {@link Group} 
+ * <br>
  * Project: <strong>envoy-common</strong><br>
  * File: <strong>GroupResizeEvent.java</strong><br>
  * Created: <strong>25 Mar 2020</strong><br>
@@ -20,6 +24,10 @@ public class GroupResizeEvent extends Event<Long> {
 	private static final long serialVersionUID = 0L;
 
 	/**
+	 * This enum defines all possibilities for handling
+	 * {@link GroupResizeEvent}s.<br>
+	 * These can be: {@link OperationType#ADD} or {@link OperationType#REMOVE}.<br>
+	 * <br>
 	 * Project: <strong>envoy-common</strong><br>
 	 * File: <strong>GroupResizeEvent.java</strong><br>
 	 * Created: <strong>25 Mar 2020</strong><br>
@@ -29,11 +37,13 @@ public class GroupResizeEvent extends Event<Long> {
 	 */
 	public enum OperationType {
 		/**
-		 *
+		 * Select this element, if the given {@link User} should be added to the given
+		 * {@link Group}
 		 */
 		ADD,
 		/**
-		 *
+		 * Select this element, if the given {@link User} should be removed from the
+		 * given {@link Group}
 		 */
 		REMOVE
 	}

From 15338dce52f0154f7379f8828ef09133334b9928 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 25 Mar 2020 17:43:55 +0100
Subject: [PATCH 08/33] refactored all `getId()`s  to `getID()`s

---
 src/main/java/envoy/data/Contacts.java        |  2 +-
 src/main/java/envoy/data/Message.java         | 22 ++++++++--------
 src/main/java/envoy/data/MessageBuilder.java  | 26 +++++++++----------
 .../java/envoy/event/GroupResizeEvent.java    |  5 ++--
 .../envoy/event/MessageStatusChangeEvent.java |  4 +--
 .../envoy/event/UserStatusChangeEvent.java    |  2 +-
 src/main/java/module-info.java                |  2 +-
 7 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/src/main/java/envoy/data/Contacts.java b/src/main/java/envoy/data/Contacts.java
index c86c1fc..fb7f866 100644
--- a/src/main/java/envoy/data/Contacts.java
+++ b/src/main/java/envoy/data/Contacts.java
@@ -15,7 +15,7 @@ public class Contacts implements Serializable {
 
 	private final List<User> contacts;
 
-	private static final long serialVersionUID = 136970804968152871L;
+	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Creates an instance of {@link Contacts}.
diff --git a/src/main/java/envoy/data/Message.java b/src/main/java/envoy/data/Message.java
index ab26c9a..ff9a453 100644
--- a/src/main/java/envoy/data/Message.java
+++ b/src/main/java/envoy/data/Message.java
@@ -48,7 +48,7 @@ public class Message implements Serializable {
 		READ
 	}
 
-	private final long					id, senderId, recipientId;
+	private final long					id, senderID, recipientID;
 	private final boolean				forwarded;
 	private final Date					creationDate;
 	private final String				text;
@@ -66,8 +66,8 @@ public class Message implements Serializable {
 	 * properties.
 	 *
 	 * @param id           unique ID
-	 * @param senderId     the ID of the user who sends the message
-	 * @param recipientId  the ID of the user who receives the message
+	 * @param senderID     the ID of the user who sends the message
+	 * @param recipientID  the ID of the user who receives the message
 	 * @param creationDate the creation date of the message
 	 * @param text         the text content of the message
 	 * @param attachment   the attachment of the message, if present
@@ -75,11 +75,11 @@ public class Message implements Serializable {
 	 * @param forwarded    whether this message was forwarded
 	 * @since Envoy Common v0.2-alpha
 	 */
-	Message(long id, long senderId, long recipientId, Date creationDate, String text, MessageAttachment<?> attachment, MessageStatus status,
+	Message(long id, long senderID, long recipientID, Date creationDate, String text, MessageAttachment<?> attachment, MessageStatus status,
 			boolean forwarded) {
 		this.id				= id;
-		this.senderId		= senderId;
-		this.recipientId	= recipientId;
+		this.senderID		= senderID;
+		this.recipientID	= recipientID;
 		this.creationDate	= creationDate;
 		this.text			= text;
 		this.attachment		= attachment;
@@ -110,8 +110,8 @@ public class Message implements Serializable {
 		return String.format(
 				"TextMessage[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,forwarded,hasAttachment=%b]",
 				id,
-				senderId,
-				recipientId,
+				senderID,
+				recipientID,
 				new SimpleDateFormat("dd.MM.yyyy HH:mm:ss").format(creationDate),
 				status,
 				text,
@@ -123,19 +123,19 @@ public class Message implements Serializable {
 	 * @return the ID of this message
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getId() { return id; }
+	public long getID() { return id; }
 
 	/**
 	 * @return the sender ID of this message
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getSenderId() { return senderId; }
+	public long getSenderID() { return senderID; }
 
 	/**
 	 * @return the recipient ID of this message
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getRecipientId() { return recipientId; }
+	public long getRecipientID() { return recipientID; }
 
 	/**
 	 * @return the date at which this message was created
diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index 3ee6ec5..c23f663 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -17,7 +17,7 @@ import envoy.data.Message.MessageStatus;
 public class MessageBuilder {
 
 	// Mandatory properties without default values
-	private final long senderId, recipientId;
+	private final long senderID, recipientID;
 
 	// Properties with default values
 	private long					id;
@@ -31,26 +31,26 @@ public class MessageBuilder {
 	 * Creates an instance of {@link MessageBuilder} with all mandatory values
 	 * without defaults for the {@link Message} class.
 	 *
-	 * @param senderId    the ID of the user who sends the {@link Message}
-	 * @param recipientId the ID of the user who receives the {@link Message}
+	 * @param senderID    the ID of the user who sends the {@link Message}
+	 * @param recipientID the ID of the user who receives the {@link Message}
 	 * @param iDGenerator the ID generator used to generate a unique {@link Message}
 	 *                    id
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public MessageBuilder(long senderId, long recipientId, IDGenerator iDGenerator) { this(senderId, recipientId, iDGenerator.next()); }
+	public MessageBuilder(long senderID, long recipientID, IDGenerator iDGenerator) { this(senderID, recipientID, iDGenerator.next()); }
 
 	/**
 	 * Creates an instance of {@link MessageBuilder} with all mandatory values
 	 * without defaults for the {@link Message} class.
 	 *
-	 * @param senderId    the ID of the user who sends the {@link Message}
-	 * @param recipientId the ID of the user who receives the {@link Message}
+	 * @param senderID    the ID of the user who sends the {@link Message}
+	 * @param recipientID the ID of the user who receives the {@link Message}
 	 * @param messageId   the ID of the {@link Message}
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public MessageBuilder(long senderId, long recipientId, long messageId) {
-		this.senderId		= senderId;
-		this.recipientId	= recipientId;
+	public MessageBuilder(long senderID, long recipientID, long messageId) {
+		this.senderID		= senderID;
+		this.recipientID	= recipientID;
 		id					= messageId;
 	}
 
@@ -60,13 +60,13 @@ public class MessageBuilder {
 	 * This makes it especially useful in the case of forwarding messages.
 	 *
 	 * @param msg         the message to copy
-	 * @param recipientId the ID of the user who receives the {@link Message}
+	 * @param recipientID the ID of the user who receives the {@link Message}
 	 * @param iDGenerator the ID generator used to generate a unique {@link Message}
 	 *                    id
 	 * @since Envoy v0.1-beta
 	 */
-	public MessageBuilder(Message msg, long recipientId, IDGenerator iDGenerator) {
-		this(msg.getRecipientId(), recipientId, iDGenerator.next());
+	public MessageBuilder(Message msg, long recipientID, IDGenerator iDGenerator) {
+		this(msg.getRecipientID(), recipientID, iDGenerator.next());
 		this.attachment		= msg.getAttachment();
 		this.creationDate	= new Date();
 		this.forwarded		= true;
@@ -102,7 +102,7 @@ public class MessageBuilder {
 		if (text == null) text = "";
 		if (status == null) status = MessageStatus.WAITING;
 
-		return new Message(id, senderId, recipientId, creationDate, text, attachment, status, forwarded);
+		return new Message(id, senderID, recipientID, creationDate, text, attachment, status, forwarded);
 	}
 
 	/**
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index e898752..8ad2ce5 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -7,7 +7,8 @@ import envoy.data.User;
 /**
  * This event is used to communicate changes in the group size between client
  * and server.<br>
- * Possible actions are adding or removing certain {@link User}s to or from a certain {@link Group} 
+ * Possible actions are adding or removing certain {@link User}s to or from a
+ * certain {@link Group}
  * <br>
  * Project: <strong>envoy-common</strong><br>
  * File: <strong>GroupResizeEvent.java</strong><br>
@@ -93,4 +94,4 @@ public class GroupResizeEvent extends Event<Long> {
 	 */
 	@Override
 	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operationType=%b]", get(), groupID, operationType); }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/envoy/event/MessageStatusChangeEvent.java b/src/main/java/envoy/event/MessageStatusChangeEvent.java
index 0307e6e..2068c7f 100644
--- a/src/main/java/envoy/event/MessageStatusChangeEvent.java
+++ b/src/main/java/envoy/event/MessageStatusChangeEvent.java
@@ -40,13 +40,13 @@ public class MessageStatusChangeEvent extends Event<Message.MessageStatus> {
 	 * @param message the message from which to build the event
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public MessageStatusChangeEvent(Message message) { this(message.getId(), message.getStatus(), new Date()); }
+	public MessageStatusChangeEvent(Message message) { this(message.getID(), message.getStatus(), new Date()); }
 
 	/**
 	 * @return the ID of the {@link Message} this event is related to
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getId() { return id; }
+	public long getID() { return id; }
 
 	/**
 	 * @return the date at which the status change occurred
diff --git a/src/main/java/envoy/event/UserStatusChangeEvent.java b/src/main/java/envoy/event/UserStatusChangeEvent.java
index 8ab198c..2a85676 100644
--- a/src/main/java/envoy/event/UserStatusChangeEvent.java
+++ b/src/main/java/envoy/event/UserStatusChangeEvent.java
@@ -42,7 +42,7 @@ public class UserStatusChangeEvent extends Event<UserStatus> {
 	 * @return the ID of the {@link User} this event is related to
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getId() { return id; }
+	public long getID() { return id; }
 
 	@Override
 	public String toString() { return String.format("UserStatusChangeEvent[id=%d,status=%s]", id, value); }
diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
index 5cfe504..ac8ee44 100644
--- a/src/main/java/module-info.java
+++ b/src/main/java/module-info.java
@@ -15,4 +15,4 @@ module envoy.common {
 	exports envoy.event;
 
 	requires transitive java.logging;
-}
\ No newline at end of file
+}

From 05ffa34ec0410b0ca659bc1b4c886e4c0c26a2ee Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 12:45:10 +0100
Subject: [PATCH 09/33] Formatting and Refactoring

---
 src/main/java/envoy/data/Contact.java         |  7 ++--
 src/main/java/envoy/data/Group.java           | 10 +++---
 .../java/envoy/event/GroupCreationEvent.java  |  1 -
 .../java/envoy/event/GroupResizeEvent.java    | 33 +++++++++----------
 .../java/envoy/event/NameChangeEvent.java     |  4 +--
 5 files changed, 27 insertions(+), 28 deletions(-)

diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index e7a22ed..870aec8 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -23,7 +23,7 @@ public abstract class Contact implements Serializable {
 	/**
 	 * Creates a new instance of a {@link Contact}.
 	 *
-	 * @param id   the id of this contact
+	 * @param id   the ID of this contact
 	 * @param name the name of this contact
 	 * @since Envoy Common v0.1-beta
 	 */
@@ -45,12 +45,13 @@ public abstract class Contact implements Serializable {
 	public String getName() { return name; }
 
 	/**
-	 * @param newName the new name of this {@link Contact}
+	 * @param name the new name of this {@link Contact}
 	 * @since Envoy Common v0.1-beta
 	 */
-	public void setName(String newName) { name = newName; }
+	public void setName(String name) { this.name = name; }
 
 	/**
+	 * 
 	 * {@inheritDoc}
 	 */
 	@Override
diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index 44f91d4..abc51d0 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -14,15 +14,15 @@ import java.util.StringJoiner;
  */
 public class Group extends Contact {
 
-	private static final long serialVersionUID = 0L;
-
 	// TODO add admins
 	private List<Long> memberIDs;
 
+	private static final long serialVersionUID = 0L;
+
 	/**
 	 * Creates a new instance of a {@link Group}.
 	 *
-	 * @param id   the id of this group
+	 * @param id   the ID of this group
 	 * @param name the name of this group
 	 * @since Envoy Common v0.1-beta
 	 */
@@ -31,7 +31,7 @@ public class Group extends Contact {
 	/**
 	 * Creates a new instance of a {@link Group}.
 	 *
-	 * @param id        the id of this group
+	 * @param id        the ID of this group
 	 * @param name      the name of this group
 	 * @param memberIDs the IDs of all members that should be preinitialized
 	 * @since Envoy Common v0.1-beta
@@ -61,7 +61,7 @@ public class Group extends Contact {
 		var joiner = new StringJoiner(",", "Group[id=", "]");
 		joiner.add("id=" + getID());
 		joiner.add("name=" + getName());
-		joiner.add("memberIDs=" + getMemberIDs());
+		joiner.add("members=" + getMemberIDs().size());
 		return joiner.toString();
 	}
 }
diff --git a/src/main/java/envoy/event/GroupCreationEvent.java b/src/main/java/envoy/event/GroupCreationEvent.java
index a2d393c..17810e9 100644
--- a/src/main/java/envoy/event/GroupCreationEvent.java
+++ b/src/main/java/envoy/event/GroupCreationEvent.java
@@ -19,5 +19,4 @@ public class GroupCreationEvent extends Event<String> {
 	 * @since Envoy Common v0.1-beta
 	 */
 	public GroupCreationEvent(String value) { super(value); }
-
 }
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index 8ad2ce5..af09c35 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -20,14 +20,14 @@ import envoy.data.User;
 public class GroupResizeEvent extends Event<Long> {
 
 	private final long		groupID;
-	private OperationType	operationType;
+	private Operation	operation;
 
 	private static final long serialVersionUID = 0L;
 
 	/**
 	 * This enum defines all possibilities for handling
 	 * {@link GroupResizeEvent}s.<br>
-	 * These can be: {@link OperationType#ADD} or {@link OperationType#REMOVE}.<br>
+	 * These can be: {@link Operation#ADD} or {@link Operation#REMOVE}.<br>
 	 * <br>
 	 * Project: <strong>envoy-common</strong><br>
 	 * File: <strong>GroupResizeEvent.java</strong><br>
@@ -36,7 +36,7 @@ public class GroupResizeEvent extends Event<Long> {
 	 * @author Leon Hofmeister
 	 * @since Envoy Common v0.1-beta
 	 */
-	public enum OperationType {
+	public enum Operation {
 		/**
 		 * Select this element, if the given {@link User} should be added to the given
 		 * {@link Group}
@@ -53,45 +53,44 @@ public class GroupResizeEvent extends Event<Long> {
 	 * Initializes a {@link GroupResizeEvent} through a Contact where the name has
 	 * already been set.
 	 *
-	 * @param user          the {@link User} who wants to join or leave a group
-	 * @param group         the {@link Group} he wants to join or leave
-	 * @param operationType whether the user should be removed from this group. If
-	 *                      false,
-	 *                      this user will be added
+	 * @param user      the {@link User} who wants to join or leave a group
+	 * @param group     the {@link Group} he wants to join or leave
+	 * @param operation whether the user should be removed from this group. If
+	 *                  false, this user will be added.
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public GroupResizeEvent(User user, Group group, OperationType operationType) {
+	public GroupResizeEvent(User user, Group group, Operation operation) {
 		super(user.getID());
 		if (group.getMemberIDs().contains(user.getID())) {
-			if (operationType.equals(OperationType.ADD)) throw new IllegalStateException(
+			if (operation.equals(Operation.ADD)) throw new IllegalStateException(
 					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");
-		} else if (operationType.equals(OperationType.REMOVE))
+		} else if (operation.equals(Operation.REMOVE))
 			throw new IllegalStateException("Cannot remove " + user + " from group " + group.getID() + " because he is no part of this group");
 		groupID				= group.getID();
-		this.operationType	= operationType;
+		this.operation	= operation;
 	}
 
 	/**
 	 * @return the ID of the {@link Contact} this event is related to
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getGroupId() { return groupID; }
+	public long getGroupID() { return groupID; }
 
 	/**
 	 * @return the operationType
 	 * @since Envoy Common v0.1-beta
 	 */
-	public OperationType getOperationType() { return operationType; }
+	public Operation getOperationType() { return operation; }
 
 	/**
-	 * @param operationType the operationType to set
+	 * @param operation the operationType to set
 	 * @since Envoy Common v0.1-beta
 	 */
-	public void setOperationType(OperationType operationType) { this.operationType = operationType; }
+	public void setOperationType(Operation operation) { this.operation = operation; }
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
-	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operationType=%b]", get(), groupID, operationType); }
+	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operation=%b]", get(), groupID, operation); }
 }
diff --git a/src/main/java/envoy/event/NameChangeEvent.java b/src/main/java/envoy/event/NameChangeEvent.java
index 4cfa640..76f6e46 100644
--- a/src/main/java/envoy/event/NameChangeEvent.java
+++ b/src/main/java/envoy/event/NameChangeEvent.java
@@ -16,8 +16,9 @@ import envoy.data.Contact;
  */
 public class NameChangeEvent extends Event<String> {
 
+	private final long id;
+
 	private static final long	serialVersionUID	= 0L;
-	private final long			id;
 
 	/**
 	 * Creates a new {@link NameChangeEvent} for a user or a group.
@@ -48,5 +49,4 @@ public class NameChangeEvent extends Event<String> {
 
 	@Override
 	public String toString() { return String.format("NameChangeEvent[id=%d,name=%s]", id, value); }
-
 }

From 1909b9748ac86667fb960c637a0fb60163ea84ac Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 15:43:30 +0100
Subject: [PATCH 10/33] Changed String in toString method

---
 src/main/java/envoy/event/GroupResizeEvent.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index af09c35..be5ac33 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -92,5 +92,5 @@ public class GroupResizeEvent extends Event<Long> {
 	 * {@inheritDoc}
 	 */
 	@Override
-	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operation=%b]", get(), groupID, operation); }
+	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operation=%s]", get(), groupID, operation); }
 }

From 4a26ef8c4a39acc6a580e6e6afed49c3ce1e2c5b Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 15:49:08 +0100
Subject: [PATCH 11/33] Revised

---
 src/main/java/envoy/data/Group.java             |  8 +-------
 src/main/java/envoy/event/GroupResizeEvent.java | 10 ++--------
 2 files changed, 3 insertions(+), 15 deletions(-)

diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index abc51d0..077ff40 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -15,7 +15,7 @@ import java.util.StringJoiner;
 public class Group extends Contact {
 
 	// TODO add admins
-	private List<Long> memberIDs;
+	private final List<Long> memberIDs;
 
 	private static final long serialVersionUID = 0L;
 
@@ -47,12 +47,6 @@ public class Group extends Contact {
 	 */
 	public List<Long> getMemberIDs() { return memberIDs; }
 
-	/**
-	 * @param memberIDs the member IDs to set
-	 * @since Envoy Common v0.1-beta
-	 */
-	public void setMemberIDs(List<Long> memberIDs) { this.memberIDs = memberIDs; }
-
 	/**
 	 * {@inheritDoc}
 	 */
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index be5ac33..110ea9b 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -20,7 +20,7 @@ import envoy.data.User;
 public class GroupResizeEvent extends Event<Long> {
 
 	private final long		groupID;
-	private Operation	operation;
+	private final Operation	operation;
 
 	private static final long serialVersionUID = 0L;
 
@@ -80,13 +80,7 @@ public class GroupResizeEvent extends Event<Long> {
 	 * @return the operationType
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Operation getOperationType() { return operation; }
-
-	/**
-	 * @param operation the operationType to set
-	 * @since Envoy Common v0.1-beta
-	 */
-	public void setOperationType(Operation operation) { this.operation = operation; }
+	public Operation getOperation() { return operation; }
 
 	/**
 	 * {@inheritDoc}

From a3e7034713fee4bf99774125465ddb912bcff02a Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 18:55:48 +0100
Subject: [PATCH 12/33] Revised message related classes

Added GroupMessage class as subclass from Message and adjusted the
MessageBuilder
---
 .classpath                                   | 56 ++++++++++----------
 .settings/org.eclipse.jdt.ui.prefs           |  2 +-
 src/main/java/envoy/data/GroupMessage.java   | 46 ++++++++++++++++
 src/main/java/envoy/data/MessageBuilder.java | 17 ++++--
 4 files changed, 89 insertions(+), 32 deletions(-)
 create mode 100644 src/main/java/envoy/data/GroupMessage.java

diff --git a/.classpath b/.classpath
index 7d2ffae..3603647 100644
--- a/.classpath
+++ b/.classpath
@@ -1,28 +1,28 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<classpath>
-	<classpathentry kind="src" output="target/classes" path="src/main/java">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="test" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
-		<attributes>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="org.eclipse.jst.component.nondependency" value=""/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
-		<attributes>
-			<attribute name="maven.pomderived" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="output" path="target/classes"/>
-</classpath>
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" output="target/classes" path="src/main/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="test" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="org.eclipse.jst.component.nondependency" value=""/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="output" path="target/classes"/>
+</classpath>
diff --git a/.settings/org.eclipse.jdt.ui.prefs b/.settings/org.eclipse.jdt.ui.prefs
index f2ac36a..1a7acd7 100644
--- a/.settings/org.eclipse.jdt.ui.prefs
+++ b/.settings/org.eclipse.jdt.ui.prefs
@@ -1,3 +1,3 @@
 eclipse.preferences.version=1
 org.eclipse.jdt.ui.javadoc=true
-org.eclipse.jdt.ui.text.custom_code_templates=<?xml version\="1.0" encoding\="UTF-8" standalone\="no"?><templates><template autoinsert\="false" context\="gettercomment_context" deleted\="false" description\="Comment for getter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.gettercomment" name\="gettercomment">/**\n * @return the ${bare_field_name}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="settercomment_context" deleted\="false" description\="Comment for setter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.settercomment" name\="settercomment">/**\n * @param ${param} the ${bare_field_name} to set\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="constructorcomment_context" deleted\="false" description\="Comment for created constructors" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorcomment" name\="constructorcomment">/**\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="filecomment_context" deleted\="false" description\="Comment for created Java files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.filecomment" name\="filecomment"/><template autoinsert\="false" context\="typecomment_context" deleted\="false" description\="Comment for created types" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.typecomment" name\="typecomment">/**\n * Project\: &lt;strong&gt;${project_name}&lt;/strong&gt;&lt;br&gt;\n * File\: &lt;strong&gt;${file_name}&lt;/strong&gt;&lt;br&gt;\n * Created\: &lt;strong&gt;${date}&lt;/strong&gt;&lt;br&gt;\n * \n * @author ${user}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="fieldcomment_context" deleted\="false" description\="Comment for fields" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.fieldcomment" name\="fieldcomment"/><template autoinsert\="false" context\="methodcomment_context" deleted\="false" description\="Comment for non-overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodcomment" name\="methodcomment">/**\n * ${tags}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="modulecomment_context" deleted\="false" description\="Comment for modules" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.modulecomment" name\="modulecomment">/**\n * @author ${user}\n *\n * ${tags}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="false" context\="overridecomment_context" deleted\="false" description\="Comment for overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.overridecomment" name\="overridecomment">/**\n * {@inheritDoc}\n */</template><template autoinsert\="false" context\="delegatecomment_context" deleted\="false" description\="Comment for delegate methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.delegatecomment" name\="delegatecomment">/**\n * ${tags}\n * ${see_to_target}\n * @since Envoy Common v0.1-beta\n */</template><template autoinsert\="true" context\="newtype_context" deleted\="false" description\="Newly created files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.newtype" name\="newtype">${filecomment}\n${package_declaration}\n\n${typecomment}\n${type_declaration}</template><template autoinsert\="true" context\="classbody_context" deleted\="false" description\="Code in new class type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.classbody" name\="classbody">\n</template><template autoinsert\="true" context\="interfacebody_context" deleted\="false" description\="Code in new interface type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.interfacebody" name\="interfacebody">\n</template><template autoinsert\="true" context\="enumbody_context" deleted\="false" description\="Code in new enum type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.enumbody" name\="enumbody">\n</template><template autoinsert\="true" context\="annotationbody_context" deleted\="false" description\="Code in new annotation type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.annotationbody" name\="annotationbody">\n</template><template autoinsert\="false" context\="catchblock_context" deleted\="false" description\="Code in new catch blocks" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.catchblock" name\="catchblock">${exception_var}.printStackTrace();</template><template autoinsert\="false" context\="methodbody_context" deleted\="false" description\="Code in created method stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodbody" name\="methodbody">${body_statement}</template><template autoinsert\="false" context\="constructorbody_context" deleted\="false" description\="Code in created constructor stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorbody" name\="constructorbody">${body_statement}</template><template autoinsert\="true" context\="getterbody_context" deleted\="false" description\="Code in created getters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.getterbody" name\="getterbody">return ${field};</template><template autoinsert\="true" context\="setterbody_context" deleted\="false" description\="Code in created setters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.setterbody" name\="setterbody">${field} \= ${param};</template></templates>
+org.eclipse.jdt.ui.text.custom_code_templates=<?xml version\="1.0" encoding\="UTF-8" standalone\="no"?><templates><template autoinsert\="false" context\="gettercomment_context" deleted\="false" description\="Comment for getter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.gettercomment" name\="gettercomment">/**\r\n * @return the ${bare_field_name}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="settercomment_context" deleted\="false" description\="Comment for setter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.settercomment" name\="settercomment">/**\r\n * @param ${param} the ${bare_field_name} to set\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="constructorcomment_context" deleted\="false" description\="Comment for created constructors" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorcomment" name\="constructorcomment">/**\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="filecomment_context" deleted\="false" description\="Comment for created Java files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.filecomment" name\="filecomment"/><template autoinsert\="false" context\="typecomment_context" deleted\="false" description\="Comment for created types" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.typecomment" name\="typecomment">/**\r\n * Project\: &lt;strong&gt;${project_name}&lt;/strong&gt;&lt;br&gt;\r\n * File\: &lt;strong&gt;${file_name}&lt;/strong&gt;&lt;br&gt;\r\n * Created\: &lt;strong&gt;${date}&lt;/strong&gt;&lt;br&gt;\r\n * \r\n * @author ${user}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="fieldcomment_context" deleted\="false" description\="Comment for fields" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.fieldcomment" name\="fieldcomment"/><template autoinsert\="false" context\="methodcomment_context" deleted\="false" description\="Comment for non-overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodcomment" name\="methodcomment">/**\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="modulecomment_context" deleted\="false" description\="Comment for modules" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.modulecomment" name\="modulecomment">/**\r\n * @author ${user}\r\n *\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="overridecomment_context" deleted\="false" description\="Comment for overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.overridecomment" name\="overridecomment">/**\r\n * {@inheritDoc}\r\n */</template><template autoinsert\="false" context\="delegatecomment_context" deleted\="false" description\="Comment for delegate methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.delegatecomment" name\="delegatecomment">/**\r\n * ${tags}\r\n * ${see_to_target}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="true" context\="newtype_context" deleted\="false" description\="Newly created files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.newtype" name\="newtype">${filecomment}\r\n${package_declaration}\r\n\r\n${typecomment}\r\n${type_declaration}</template><template autoinsert\="true" context\="classbody_context" deleted\="false" description\="Code in new class type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.classbody" name\="classbody">\r\n</template><template autoinsert\="true" context\="interfacebody_context" deleted\="false" description\="Code in new interface type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.interfacebody" name\="interfacebody">\r\n</template><template autoinsert\="true" context\="enumbody_context" deleted\="false" description\="Code in new enum type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.enumbody" name\="enumbody">\r\n</template><template autoinsert\="true" context\="annotationbody_context" deleted\="false" description\="Code in new annotation type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.annotationbody" name\="annotationbody">\r\n</template><template autoinsert\="false" context\="catchblock_context" deleted\="false" description\="Code in new catch blocks" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.catchblock" name\="catchblock">${exception_var}.printStackTrace();</template><template autoinsert\="false" context\="methodbody_context" deleted\="false" description\="Code in created method stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodbody" name\="methodbody">${body_statement}</template><template autoinsert\="false" context\="constructorbody_context" deleted\="false" description\="Code in created constructor stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorbody" name\="constructorbody">${body_statement}</template><template autoinsert\="true" context\="getterbody_context" deleted\="false" description\="Code in created getters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.getterbody" name\="getterbody">return ${field};</template><template autoinsert\="true" context\="setterbody_context" deleted\="false" description\="Code in created setters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.setterbody" name\="setterbody">${field} \= ${param};</template></templates>
diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
new file mode 100644
index 0000000..ec2e773
--- /dev/null
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -0,0 +1,46 @@
+package envoy.data;
+
+import java.util.Date;
+import java.util.Map;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>GroupMessage.java</strong><br>
+ * Created: <strong>26.03.2020</strong><br>
+ * 
+ * @author Maximilian K&auml;fer
+ * @since Envoy Common v0.1-beta
+ */
+public final class GroupMessage extends Message {
+
+	private final Map<Long, MessageStatus> memberStatuses;
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Initializes a {@link GroupMessage} with values for all of its properties. The
+	 * use
+	 * of this constructor is only intended for the {@link MessageBuilder} class, as
+	 * this class provides {@code null} checks and default values for all
+	 * properties.
+	 *
+	 * @param id             unique ID
+	 * @param senderID       the ID of the user who sends the message
+	 * @param recipientID    the ID of the user who receives the message
+	 * @param creationDate   the creation date of the message
+	 * @param text           the text content of the message
+	 * @param attachment     the attachment of the message, if present
+	 * @param status         the current {@link MessageStatus} of the message
+	 * @param forwarded      whether this message was forwarded
+	 * @param memberStatuses a map of all members and their status according to this
+	 *                       {@link GroupMessage}
+	 * @since Envoy Common v0.1-beta
+	 */
+	GroupMessage(long id, long senderID, long groupID, Date creationDate, String text, MessageAttachment<?> attachment, MessageStatus status,
+			boolean forwarded, Map<Long, MessageStatus> memberStatuses) {
+		super(id, senderID, groupID, creationDate, text, attachment, status, forwarded);
+		this.memberStatuses = memberStatuses;
+	}
+
+	public Map<Long, MessageStatus> getMemberStatuses() { return memberStatuses; }
+}
diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index c23f663..34dc3f1 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -1,6 +1,7 @@
 package envoy.data;
 
 import java.util.Date;
+import java.util.HashMap;
 
 import envoy.data.Message.MessageStatus;
 
@@ -97,12 +98,22 @@ public class MessageBuilder {
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public Message build() {
-		// Supplement default values
+		supplyDefaults();
+		return new Message(id, senderID, recipientID, creationDate, text, attachment, status, forwarded);
+	}
+
+	public GroupMessage buildGroupMessage(Group group) {
+		if (group == null) throw new NullPointerException();
+		supplyDefaults();
+		var memberStatuses = new HashMap<Long, Message.MessageStatus>();
+		group.getMemberIDs().forEach(id -> memberStatuses.put(id, MessageStatus.WAITING));
+		return new GroupMessage(id, senderID, recipientID, creationDate, text, attachment, status, forwarded, memberStatuses);
+	}
+
+	private void supplyDefaults() {
 		if (creationDate == null) creationDate = new Date();
 		if (text == null) text = "";
 		if (status == null) status = MessageStatus.WAITING;
-
-		return new Message(id, senderID, recipientID, creationDate, text, attachment, status, forwarded);
 	}
 
 	/**

From f128c2f3079fa6e6d19e3810d3c8bd7b2333b761 Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 20:03:20 +0100
Subject: [PATCH 13/33] Added updateStatus method

---
 src/main/java/envoy/data/GroupMessage.java | 3 +++
 src/main/java/module-info.java             | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
index ec2e773..c048fe4 100644
--- a/src/main/java/envoy/data/GroupMessage.java
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -1,5 +1,6 @@
 package envoy.data;
 
+import java.util.Collections;
 import java.util.Date;
 import java.util.Map;
 
@@ -42,5 +43,7 @@ public final class GroupMessage extends Message {
 		this.memberStatuses = memberStatuses;
 	}
 
+	public void updateStatus() { setStatus(Collections.min(memberStatuses.values())); }
+
 	public Map<Long, MessageStatus> getMemberStatuses() { return memberStatuses; }
 }
diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
index ac8ee44..7177d83 100644
--- a/src/main/java/module-info.java
+++ b/src/main/java/module-info.java
@@ -5,7 +5,7 @@
  * @author Leon Hofmeister
  * @author Maximilian K&auml;fer
  * @author Kai S.K. Engelbart
- * @since Envoy common v0.1-beta
+ * @since Envoy Common v0.1-beta
  */
 module envoy.common {
 

From c511e482d34d9315c06da004f8ceb1ea1d9de4ec Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 26 Mar 2020 20:54:20 +0100
Subject: [PATCH 14/33] Implemented the setting of the received- and read-date
 of group messages

---
 src/main/java/envoy/data/GroupMessage.java | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
index c048fe4..5845c2a 100644
--- a/src/main/java/envoy/data/GroupMessage.java
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -43,7 +43,18 @@ public final class GroupMessage extends Message {
 		this.memberStatuses = memberStatuses;
 	}
 
-	public void updateStatus() { setStatus(Collections.min(memberStatuses.values())); }
+	public void updateStatus() {
+		setStatus(Collections.min(memberStatuses.values()));
+		switch (getStatus()) {
+			case RECEIVED:
+				setReceivedDate(new Date());
+				break;
+
+			case READ:
+				setReadDate(new Date());
+				break;
+		}
+	}
 
 	public Map<Long, MessageStatus> getMemberStatuses() { return memberStatuses; }
 }

From 2d99a3785e55c9f0dbb131383f2fa504dedacc27 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Sat, 28 Mar 2020 15:21:02 +0100
Subject: [PATCH 15/33] Created ContactDeletionEvent and equals- + hashcode-
 method for Contact

additionally extracted enum ElementOperation and fixed wrong
toString-method in Message
---
 src/main/java/envoy/data/Contact.java         |  20 ++-
 src/main/java/envoy/data/GroupMessage.java    | 129 ++++++++++--------
 src/main/java/envoy/data/Message.java         |   3 +-
 src/main/java/envoy/data/MessageBuilder.java  |  25 ++++
 .../java/envoy/event/ElementOperation.java    |  26 ++++
 .../java/envoy/event/GroupCreationEvent.java  |   4 +-
 .../java/envoy/event/GroupResizeEvent.java    |  43 ++----
 .../event/contact/ContactDeletionEvent.java   |  26 ++++
 .../{ => contact}/ContactOperationEvent.java  |  35 +----
 .../{ => contact}/ContactSearchRequest.java   |   4 +-
 .../{ => contact}/ContactSearchResult.java    |   3 +-
 .../envoy/event/contact/package-info.java     |  13 ++
 src/main/java/module-info.java                |   1 +
 13 files changed, 202 insertions(+), 130 deletions(-)
 create mode 100644 src/main/java/envoy/event/ElementOperation.java
 create mode 100644 src/main/java/envoy/event/contact/ContactDeletionEvent.java
 rename src/main/java/envoy/event/{ => contact}/ContactOperationEvent.java (51%)
 rename src/main/java/envoy/event/{ => contact}/ContactSearchRequest.java (91%)
 rename src/main/java/envoy/event/{ => contact}/ContactSearchResult.java (92%)
 create mode 100644 src/main/java/envoy/event/contact/package-info.java

diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index 870aec8..53992c6 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -1,6 +1,7 @@
 package envoy.data;
 
 import java.io.Serializable;
+import java.util.Objects;
 
 /**
  * This class is the superclass for both {@link User} and {@link Group}.<br>
@@ -16,7 +17,7 @@ import java.io.Serializable;
 public abstract class Contact implements Serializable {
 
 	private final long	id;
-	private String	name;
+	private String		name;
 
 	private static final long serialVersionUID = 0L;
 
@@ -51,9 +52,24 @@ public abstract class Contact implements Serializable {
 	public void setName(String name) { this.name = name; }
 
 	/**
-	 * 
 	 * {@inheritDoc}
 	 */
 	@Override
 	public String toString() { return String.format("Contact[id=%d,name=%s]", id, name); }
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public int hashCode() { return Objects.hash(id); }
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) return true;
+		if (!(obj instanceof Contact)) return false;
+		return id == ((Contact) obj).id;
+	}
 }
diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
index 5845c2a..b1c05ce 100644
--- a/src/main/java/envoy/data/GroupMessage.java
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -1,60 +1,69 @@
-package envoy.data;
-
-import java.util.Collections;
-import java.util.Date;
-import java.util.Map;
-
-/**
- * Project: <strong>envoy-common</strong><br>
- * File: <strong>GroupMessage.java</strong><br>
- * Created: <strong>26.03.2020</strong><br>
- * 
- * @author Maximilian K&auml;fer
- * @since Envoy Common v0.1-beta
- */
-public final class GroupMessage extends Message {
-
-	private final Map<Long, MessageStatus> memberStatuses;
-
-	private static final long serialVersionUID = 0L;
-
-	/**
-	 * Initializes a {@link GroupMessage} with values for all of its properties. The
-	 * use
-	 * of this constructor is only intended for the {@link MessageBuilder} class, as
-	 * this class provides {@code null} checks and default values for all
-	 * properties.
-	 *
-	 * @param id             unique ID
-	 * @param senderID       the ID of the user who sends the message
-	 * @param recipientID    the ID of the user who receives the message
-	 * @param creationDate   the creation date of the message
-	 * @param text           the text content of the message
-	 * @param attachment     the attachment of the message, if present
-	 * @param status         the current {@link MessageStatus} of the message
-	 * @param forwarded      whether this message was forwarded
-	 * @param memberStatuses a map of all members and their status according to this
-	 *                       {@link GroupMessage}
-	 * @since Envoy Common v0.1-beta
-	 */
-	GroupMessage(long id, long senderID, long groupID, Date creationDate, String text, MessageAttachment<?> attachment, MessageStatus status,
-			boolean forwarded, Map<Long, MessageStatus> memberStatuses) {
-		super(id, senderID, groupID, creationDate, text, attachment, status, forwarded);
-		this.memberStatuses = memberStatuses;
-	}
-
-	public void updateStatus() {
-		setStatus(Collections.min(memberStatuses.values()));
-		switch (getStatus()) {
-			case RECEIVED:
-				setReceivedDate(new Date());
-				break;
-
-			case READ:
-				setReadDate(new Date());
-				break;
-		}
-	}
-
-	public Map<Long, MessageStatus> getMemberStatuses() { return memberStatuses; }
-}
+package envoy.data;
+
+import java.util.Collections;
+import java.util.Date;
+import java.util.Map;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>GroupMessage.java</strong><br>
+ * Created: <strong>26.03.2020</strong><br>
+ *
+ * @author Maximilian K&auml;fer
+ * @since Envoy Common v0.1-beta
+ */
+public final class GroupMessage extends Message {
+
+	private final Map<Long, MessageStatus> memberStatuses;
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * Initializes a {@link GroupMessage} with values for all of its properties. The
+	 * use
+	 * of this constructor is only intended for the {@link MessageBuilder} class, as
+	 * this class provides {@code null} checks and default values for all
+	 * properties.
+	 *
+	 * @param id             unique ID
+	 * @param senderID       the ID of the user who sends the message
+	 * @param recipientID    the ID of the user who receives the message
+	 * @param creationDate   the creation date of the message
+	 * @param text           the text content of the message
+	 * @param attachment     the attachment of the message, if present
+	 * @param status         the current {@link MessageStatus} of the message
+	 * @param forwarded      whether this message was forwarded
+	 * @param memberStatuses a map of all members and their status according to this
+	 *                       {@link GroupMessage}
+	 * @since Envoy Common v0.1-beta
+	 */
+	GroupMessage(long id, long senderID, long groupID, Date creationDate, String text, MessageAttachment<?> attachment, MessageStatus status,
+			boolean forwarded, Map<Long, MessageStatus> memberStatuses) {
+		super(id, senderID, groupID, creationDate, text, attachment, status, forwarded);
+		this.memberStatuses = memberStatuses;
+	}
+
+	/**
+	 * Sets the status to be the minimum of all members.
+	 *
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void updateStatus() {
+		setStatus(Collections.min(memberStatuses.values()));
+		switch (getStatus()) {
+			case RECEIVED:
+				setReceivedDate(new Date());
+				break;
+
+			case READ:
+				setReadDate(new Date());
+				break;
+		}
+	}
+
+	/**
+	 * @return the map of all statuses in this {@link GroupMessage}
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Map<Long, MessageStatus> getMemberStatuses() { return memberStatuses; }
+}
diff --git a/src/main/java/envoy/data/Message.java b/src/main/java/envoy/data/Message.java
index ff9a453..ec7faf4 100644
--- a/src/main/java/envoy/data/Message.java
+++ b/src/main/java/envoy/data/Message.java
@@ -107,8 +107,7 @@ public class Message implements Serializable {
 
 	@Override
 	public String toString() {
-		return String.format(
-				"TextMessage[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,forwarded,hasAttachment=%b]",
+		return String.format("Message[id=%d,sender=%s,recipient=%s,date=%s,status=%s,text=%s,forwarded=%b,hasAttachment=%b]",
 				id,
 				senderID,
 				recipientID,
diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index 34dc3f1..c1a5c6f 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -102,6 +102,31 @@ public class MessageBuilder {
 		return new Message(id, senderID, recipientID, creationDate, text, attachment, status, forwarded);
 	}
 
+	/**
+	 * Creates an instance of {@link GroupMessage} with the previously supplied
+	 * values. If a mandatory value is not set, a default value will be used
+	 * instead:<br>
+	 * <br>
+	 * <table border="1">
+	 * <tr>
+	 * <td>{@code date}</td>
+	 * <td>{@code new Date()}</td>
+	 * <tr>
+	 * <tr>
+	 * <td>{@code text}</td>
+	 * <td>{@code ""}</td>
+	 * <tr>
+	 * <tr>
+	 * <td>{@code status}</td>
+	 * <td>{@code MessageStatus.WAITING}</td>
+	 * <tr>
+	 * </table>
+	 *
+	 * @param group the {@link Group} that is used to fill the map of member
+	 *              statuses
+	 * @return a new instance of {@link GroupMessage}
+	 * @since Envoy Common v0.2-alpha
+	 */
 	public GroupMessage buildGroupMessage(Group group) {
 		if (group == null) throw new NullPointerException();
 		supplyDefaults();
diff --git a/src/main/java/envoy/event/ElementOperation.java b/src/main/java/envoy/event/ElementOperation.java
new file mode 100644
index 0000000..e0ed0df
--- /dev/null
+++ b/src/main/java/envoy/event/ElementOperation.java
@@ -0,0 +1,26 @@
+package envoy.event;
+
+/**
+ * This enum declares all modification possibilities for a given container.<br>
+ * These can be: {@link ElementOperation#ADD} or
+ * {@link ElementOperation#REMOVE}.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>ElementOperation.java</strong><br>
+ * Created: <strong>25 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public enum ElementOperation {
+	/**
+	 * Select this element, if the given element should be added to the given
+	 * container
+	 */
+	ADD,
+	/**
+	 * Select this element, if the given element should be removed from the given
+	 * container
+	 */
+	REMOVE
+}
diff --git a/src/main/java/envoy/event/GroupCreationEvent.java b/src/main/java/envoy/event/GroupCreationEvent.java
index 17810e9..5b6d365 100644
--- a/src/main/java/envoy/event/GroupCreationEvent.java
+++ b/src/main/java/envoy/event/GroupCreationEvent.java
@@ -1,8 +1,8 @@
 package envoy.event;
 
 /**
- * This event creates a group with the given name.
- *
+ * This event creates a group with the given name.<br>
+ * <br>
  * Project: <strong>envoy-common</strong><br>
  * File: <strong>GroupCreationEvent.java</strong><br>
  * Created: <strong>25 Mar 2020</strong><br>
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index 110ea9b..24f4ac8 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -19,54 +19,29 @@ import envoy.data.User;
  */
 public class GroupResizeEvent extends Event<Long> {
 
-	private final long		groupID;
-	private final Operation	operation;
+	private final long				groupID;
+	private final ElementOperation	operation;
 
 	private static final long serialVersionUID = 0L;
 
-	/**
-	 * This enum defines all possibilities for handling
-	 * {@link GroupResizeEvent}s.<br>
-	 * These can be: {@link Operation#ADD} or {@link Operation#REMOVE}.<br>
-	 * <br>
-	 * Project: <strong>envoy-common</strong><br>
-	 * File: <strong>GroupResizeEvent.java</strong><br>
-	 * Created: <strong>25 Mar 2020</strong><br>
-	 *
-	 * @author Leon Hofmeister
-	 * @since Envoy Common v0.1-beta
-	 */
-	public enum Operation {
-		/**
-		 * Select this element, if the given {@link User} should be added to the given
-		 * {@link Group}
-		 */
-		ADD,
-		/**
-		 * Select this element, if the given {@link User} should be removed from the
-		 * given {@link Group}
-		 */
-		REMOVE
-	}
-
 	/**
 	 * Initializes a {@link GroupResizeEvent} through a Contact where the name has
 	 * already been set.
 	 *
 	 * @param user      the {@link User} who wants to join or leave a group
 	 * @param group     the {@link Group} he wants to join or leave
-	 * @param operation whether the user should be removed from this group. If
-	 *                  false, this user will be added.
+	 * @param operation describes what to do with the given user:<br>
+	 *                  add him to this group or remove him from it
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public GroupResizeEvent(User user, Group group, Operation operation) {
+	public GroupResizeEvent(User user, Group group, ElementOperation operation) {
 		super(user.getID());
 		if (group.getMemberIDs().contains(user.getID())) {
-			if (operation.equals(Operation.ADD)) throw new IllegalStateException(
+			if (operation.equals(ElementOperation.ADD)) throw new IllegalStateException(
 					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");
-		} else if (operation.equals(Operation.REMOVE))
+		} else if (operation.equals(ElementOperation.REMOVE))
 			throw new IllegalStateException("Cannot remove " + user + " from group " + group.getID() + " because he is no part of this group");
-		groupID				= group.getID();
+		groupID			= group.getID();
 		this.operation	= operation;
 	}
 
@@ -80,7 +55,7 @@ public class GroupResizeEvent extends Event<Long> {
 	 * @return the operationType
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Operation getOperation() { return operation; }
+	public ElementOperation getOperation() { return operation; }
 
 	/**
 	 * {@inheritDoc}
diff --git a/src/main/java/envoy/event/contact/ContactDeletionEvent.java b/src/main/java/envoy/event/contact/ContactDeletionEvent.java
new file mode 100644
index 0000000..79c13d1
--- /dev/null
+++ b/src/main/java/envoy/event/contact/ContactDeletionEvent.java
@@ -0,0 +1,26 @@
+package envoy.event.contact;
+
+import envoy.data.Contact;
+import envoy.event.Event;
+
+/**
+ * This event is sent if a {@link Contact} has been deleted/ has decided to
+ * delete himself.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>ContactDeletionEvent.java</strong><br>
+ * Created: <strong>28 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+public class ContactDeletionEvent extends Event<Long> {
+
+	private static final long serialVersionUID = 0L;
+
+	/**
+	 * @param value the id of the {@link Contact} being deleted
+	 * @since Envoy Common v0.1-beta
+	 */
+	protected ContactDeletionEvent(Long value) { super(value); }
+}
diff --git a/src/main/java/envoy/event/ContactOperationEvent.java b/src/main/java/envoy/event/contact/ContactOperationEvent.java
similarity index 51%
rename from src/main/java/envoy/event/ContactOperationEvent.java
rename to src/main/java/envoy/event/contact/ContactOperationEvent.java
index 9fe505d..59a08cf 100644
--- a/src/main/java/envoy/event/ContactOperationEvent.java
+++ b/src/main/java/envoy/event/contact/ContactOperationEvent.java
@@ -1,6 +1,8 @@
-package envoy.event;
+package envoy.event.contact;
 
 import envoy.data.User;
+import envoy.event.ElementOperation;
+import envoy.event.Event;
 
 /**
  * Signifies the modification of a contact list.<br>
@@ -14,32 +16,9 @@ import envoy.data.User;
  */
 public class ContactOperationEvent extends Event<User> {
 
-	/**
-	 * Specifies the operation performed on a contact list.<br>
-	 * <br>
-	 * Project: <strong>envoy-common</strong><br>
-	 * File: <strong>ContactOperationEvent.java</strong><br>
-	 * Created: <strong>05.02.2020</strong><br>
-	 *
-	 * @author Maximilian K&auml;fer
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public enum Operation {
+	private final ElementOperation operationType;
 
-		/**
-		 * Adds a user to the contact list.
-		 */
-		ADD,
-
-		/**
-		 * Removes a user from the contact list.
-		 */
-		REMOVE;
-	}
-
-	private final Operation operationType;
-
-	private static final long serialVersionUID = 0L;
+	private static final long serialVersionUID = 1L;
 
 	/**
 	 * Initializes a {@link ContactOperationEvent}.
@@ -48,7 +27,7 @@ public class ContactOperationEvent extends Event<User> {
 	 * @param operationType the type of operation to perform
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public ContactOperationEvent(User contact, Operation operationType) {
+	public ContactOperationEvent(User contact, ElementOperation operationType) {
 		super(contact);
 		this.operationType = operationType;
 	}
@@ -57,5 +36,5 @@ public class ContactOperationEvent extends Event<User> {
 	 * @return the type of operation to perform
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public Operation getOperationType() { return operationType; }
+	public ElementOperation getOperationType() { return operationType; }
 }
diff --git a/src/main/java/envoy/event/ContactSearchRequest.java b/src/main/java/envoy/event/contact/ContactSearchRequest.java
similarity index 91%
rename from src/main/java/envoy/event/ContactSearchRequest.java
rename to src/main/java/envoy/event/contact/ContactSearchRequest.java
index bd13812..e7c4f22 100644
--- a/src/main/java/envoy/event/ContactSearchRequest.java
+++ b/src/main/java/envoy/event/contact/ContactSearchRequest.java
@@ -1,4 +1,6 @@
-package envoy.event;
+package envoy.event.contact;
+
+import envoy.event.Event;
 
 /**
  * Requests a contact search from the server.<br>
diff --git a/src/main/java/envoy/event/ContactSearchResult.java b/src/main/java/envoy/event/contact/ContactSearchResult.java
similarity index 92%
rename from src/main/java/envoy/event/ContactSearchResult.java
rename to src/main/java/envoy/event/contact/ContactSearchResult.java
index 5f1691e..635d5fd 100644
--- a/src/main/java/envoy/event/ContactSearchResult.java
+++ b/src/main/java/envoy/event/contact/ContactSearchResult.java
@@ -1,8 +1,9 @@
-package envoy.event;
+package envoy.event.contact;
 
 import java.util.List;
 
 import envoy.data.User;
+import envoy.event.Event;
 
 /**
  * Contains a list of {@link User}s for which a search was performed.<br>
diff --git a/src/main/java/envoy/event/contact/package-info.java b/src/main/java/envoy/event/contact/package-info.java
new file mode 100644
index 0000000..375ea89
--- /dev/null
+++ b/src/main/java/envoy/event/contact/package-info.java
@@ -0,0 +1,13 @@
+/**
+ * This package contains all contact-related events.<br>
+ * <br>
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>package-info.java</strong><br>
+ * Created: <strong>28 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @author Maximilian K&auml;fer
+ * @author Kai S.K. Engelbart
+ * @since Envoy Common v0.1-beta
+ */
+package envoy.event.contact;
diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
index 7177d83..e4aa197 100644
--- a/src/main/java/module-info.java
+++ b/src/main/java/module-info.java
@@ -13,6 +13,7 @@ module envoy.common {
 	exports envoy.util;
 	exports envoy.exception;
 	exports envoy.event;
+	exports envoy.event.contact;
 
 	requires transitive java.logging;
 }

From 026b7404b2a6686f35de3527ac19d75fc3009f5d Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Sat, 28 Mar 2020 18:51:07 +0100
Subject: [PATCH 16/33] Enabled clients to have groups as contacts

---
 src/main/java/envoy/data/Contacts.java | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/envoy/data/Contacts.java b/src/main/java/envoy/data/Contacts.java
index fb7f866..71eac52 100644
--- a/src/main/java/envoy/data/Contacts.java
+++ b/src/main/java/envoy/data/Contacts.java
@@ -13,7 +13,7 @@ import java.util.List;
  */
 public class Contacts implements Serializable {
 
-	private final List<User> contacts;
+	private final List<Contact> contacts;
 
 	private static final long serialVersionUID = 0L;
 
@@ -23,7 +23,7 @@ public class Contacts implements Serializable {
 	 * @param contacts the contact list
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public Contacts(List<User> contacts) { this.contacts = contacts; }
+	public Contacts(List<Contact> contacts) { this.contacts = contacts; }
 
 	@Override
 	public String toString() { return String.format("Contacts[%s]", contacts); }
@@ -32,5 +32,5 @@ public class Contacts implements Serializable {
 	 * @return a list of users messages can be sent to
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public List<User> getContacts() { return contacts; }
+	public List<Contact> getContacts() { return contacts; }
 }

From 8cdd12e6b8d9bdc2f4437a522cb4c7e13b7dedef Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Sun, 29 Mar 2020 10:02:56 +0200
Subject: [PATCH 17/33] fixed major (spelling!) error

---
 src/main/java/envoy/data/MessageBuilder.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index c1a5c6f..79325fa 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -34,11 +34,11 @@ public class MessageBuilder {
 	 *
 	 * @param senderID    the ID of the user who sends the {@link Message}
 	 * @param recipientID the ID of the user who receives the {@link Message}
-	 * @param iDGenerator the ID generator used to generate a unique {@link Message}
+	 * @param idGenerator the ID generator used to generate a unique {@link Message}
 	 *                    id
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public MessageBuilder(long senderID, long recipientID, IDGenerator iDGenerator) { this(senderID, recipientID, iDGenerator.next()); }
+	public MessageBuilder(long senderID, long recipientID, IDGenerator idGenerator) { this(senderID, recipientID, idGenerator.next()); }
 
 	/**
 	 * Creates an instance of {@link MessageBuilder} with all mandatory values

From c41089e005986269bd3141392d7c67e2ac3e2607 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Sun, 29 Mar 2020 10:28:05 +0200
Subject: [PATCH 18/33] fixed security vulnerability (complete password hash is
 printed)

---
 src/main/java/envoy/data/LoginCredentials.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/data/LoginCredentials.java b/src/main/java/envoy/data/LoginCredentials.java
index 8007796..438dd15 100644
--- a/src/main/java/envoy/data/LoginCredentials.java
+++ b/src/main/java/envoy/data/LoginCredentials.java
@@ -54,8 +54,8 @@ public class LoginCredentials implements Serializable {
 	public String toString() {
 		try (Formatter form = new Formatter()) {
 			form.format("LoginCredentials[identifier=%s,passwordHash=", identifier);
-			for (byte element : passwordHash)
-				form.format("%02x", element);
+			for (int i = 0; i < 3; i++)
+				form.format("%02x", passwordHash[i]);
 			return form.format(",registration=%b]", registration).toString();
 		}
 	}

From 0d3316be4ac748c93d8f5377d54a3d9af0d8a1da Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 1 Apr 2020 18:09:07 +0200
Subject: [PATCH 19/33] deleted Contacts object, added contacts as part of
 Contact class

additionally:
* updated serialization method to not recurse endlessly
* refactored type of contacts from List to Set
---
 .classpath                                    | 57 ++++++++-------
 pom.xml                                       |  1 +
 src/main/java/envoy/data/Contact.java         | 26 +++++--
 src/main/java/envoy/data/Contacts.java        | 36 ---------
 src/main/java/envoy/data/Group.java           | 57 +++++++--------
 src/main/java/envoy/data/MessageBuilder.java  | 47 +++++++++---
 src/main/java/envoy/data/User.java            | 73 ++++++++++++++++---
 .../java/envoy/event/GroupCreationEvent.java  | 24 +++++-
 .../java/envoy/event/GroupResizeEvent.java    |  2 +-
 src/test/java/envoy/data/UserTest.java        | 35 +++++++++
 10 files changed, 229 insertions(+), 129 deletions(-)
 delete mode 100644 src/main/java/envoy/data/Contacts.java
 create mode 100644 src/test/java/envoy/data/UserTest.java

diff --git a/.classpath b/.classpath
index 3603647..e716709 100644
--- a/.classpath
+++ b/.classpath
@@ -1,28 +1,29 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<classpath>
-	<classpathentry kind="src" output="target/classes" path="src/main/java">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
-		<attributes>
-			<attribute name="optional" value="true"/>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="test" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
-		<attributes>
-			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="org.eclipse.jst.component.nondependency" value=""/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
-		<attributes>
-			<attribute name="maven.pomderived" value="true"/>
-		</attributes>
-	</classpathentry>
-	<classpathentry kind="output" path="target/classes"/>
-</classpath>
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" output="target/classes" path="src/main/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
+		<attributes>
+			<attribute name="optional" value="true"/>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="test" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="org.eclipse.jst.component.nondependency" value=""/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/5"/>
+	<classpathentry kind="output" path="target/classes"/>
+</classpath>
diff --git a/pom.xml b/pom.xml
index 0add6eb..98d18f7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -23,6 +23,7 @@
 				<directory>src/main/resources</directory>
 			</resource>
 		</resources>
+ 		<testSourceDirectory>src/test/java</testSourceDirectory>
 		<pluginManagement>
 			<plugins>
 				<plugin>
diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index 53992c6..b3b2d03 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -2,6 +2,7 @@ package envoy.data;
 
 import java.io.Serializable;
 import java.util.Objects;
+import java.util.Set;
 
 /**
  * This class is the superclass for both {@link User} and {@link Group}.<br>
@@ -16,21 +17,24 @@ import java.util.Objects;
  */
 public abstract class Contact implements Serializable {
 
-	private final long	id;
-	private String		name;
+	private final long								id;
+	private final transient Set<? extends Contact>	contacts;
+	private String									name;
 
 	private static final long serialVersionUID = 0L;
 
 	/**
 	 * Creates a new instance of a {@link Contact}.
 	 *
-	 * @param id   the ID of this contact
-	 * @param name the name of this contact
+	 * @param id       the ID of this contact
+	 * @param name     the name of this contact
+	 * @param contacts the {@link Contacts} of this {@link Contact}
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Contact(long id, String name) {
-		this.id		= id;
-		this.name	= name;
+	public Contact(long id, String name, Set<? extends Contact> contacts) {
+		this.id			= id;
+		this.name		= name;
+		this.contacts	= contacts;
 	}
 
 	/**
@@ -55,7 +59,7 @@ public abstract class Contact implements Serializable {
 	 * {@inheritDoc}
 	 */
 	@Override
-	public String toString() { return String.format("Contact[id=%d,name=%s]", id, name); }
+	public String toString() { return String.format("Contact[id=%d,name=%s, contacts=%s]", id, name, contacts); }
 
 	/**
 	 * {@inheritDoc}
@@ -72,4 +76,10 @@ public abstract class Contact implements Serializable {
 		if (!(obj instanceof Contact)) return false;
 		return id == ((Contact) obj).id;
 	}
+
+	/**
+	 * @return the contacts of this {@link Contact}
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Set<? extends Contact> getContacts() { return contacts; }
 }
diff --git a/src/main/java/envoy/data/Contacts.java b/src/main/java/envoy/data/Contacts.java
deleted file mode 100644
index 71eac52..0000000
--- a/src/main/java/envoy/data/Contacts.java
+++ /dev/null
@@ -1,36 +0,0 @@
-package envoy.data;
-
-import java.io.Serializable;
-import java.util.List;
-
-/**
- * Project: <strong>envoy-common</strong><br>
- * File: <strong>Contacts.java</strong><br>
- * Created: <strong>02.01.2020</strong><br>
- *
- * @author Kai S. K. Engelbart
- * @since Envoy Common v0.2-alpha
- */
-public class Contacts implements Serializable {
-
-	private final List<Contact> contacts;
-
-	private static final long serialVersionUID = 0L;
-
-	/**
-	 * Creates an instance of {@link Contacts}.
-	 *
-	 * @param contacts the contact list
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public Contacts(List<Contact> contacts) { this.contacts = contacts; }
-
-	@Override
-	public String toString() { return String.format("Contacts[%s]", contacts); }
-
-	/**
-	 * @return a list of users messages can be sent to
-	 * @since Envoy Common v0.2-alpha
-	 */
-	public List<Contact> getContacts() { return contacts; }
-}
diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index 077ff40..bec17be 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -1,8 +1,9 @@
 package envoy.data;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.StringJoiner;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * Project: <strong>envoy-common</strong><br>
@@ -12,50 +13,44 @@ import java.util.StringJoiner;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class Group extends Contact {
-
-	// TODO add admins
-	private final List<Long> memberIDs;
+public final class Group extends Contact {
 
 	private static final long serialVersionUID = 0L;
 
 	/**
-	 * Creates a new instance of a {@link Group}.
+	 * Creates a new instance of a {@link Group} without any members.
 	 *
 	 * @param id   the ID of this group
 	 * @param name the name of this group
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Group(long id, String name) { this(id, name, new ArrayList<>()); }
+	public Group(long id, String name) { this(id, name, new HashSet<User>()); }
 
 	/**
-	 * Creates a new instance of a {@link Group}.
+	 * Creates an instance of a {@link Group}.
 	 *
-	 * @param id        the ID of this group
-	 * @param name      the name of this group
-	 * @param memberIDs the IDs of all members that should be preinitialized
+	 * @param id      the ID of this group
+	 * @param name    the name of this group
+	 * @param members all members that should be preinitialized
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Group(long id, String name, List<Long> memberIDs) {
-		super(id, name);
-		this.memberIDs = memberIDs;
+	public Group(long id, String name, Set<User> members) { super(id, name, members); }
+
+	private void readObject(ObjectInputStream inputStream) throws Exception {
+		inputStream.defaultReadObject();
+		var contacts = Contact.class.getDeclaredField("contacts");
+		contacts.setAccessible(true);
+		contacts.set(this, inputStream.readObject());
 	}
 
-	/**
-	 * @return the IDs of all members of this group
-	 * @since Envoy Common v0.1-beta
-	 */
-	public List<Long> getMemberIDs() { return memberIDs; }
+	private void writeObject(ObjectOutputStream outputStream) throws Exception {
+		outputStream.defaultWriteObject();
+		getContacts().forEach(user -> user.serializeContacts(false));
+		outputStream.writeObject(getContacts());
 
-	/**
-	 * {@inheritDoc}
-	 */
+	}
+
+	@SuppressWarnings("unchecked")
 	@Override
-	public String toString() {
-		var joiner = new StringJoiner(",", "Group[id=", "]");
-		joiner.add("id=" + getID());
-		joiner.add("name=" + getName());
-		joiner.add("members=" + getMemberIDs().size());
-		return joiner.toString();
-	}
+	public Set<User> getContacts() { return (Set<User>) super.getContacts(); }
 }
diff --git a/src/main/java/envoy/data/MessageBuilder.java b/src/main/java/envoy/data/MessageBuilder.java
index 79325fa..87c6bf9 100644
--- a/src/main/java/envoy/data/MessageBuilder.java
+++ b/src/main/java/envoy/data/MessageBuilder.java
@@ -2,6 +2,7 @@ package envoy.data;
 
 import java.util.Date;
 import java.util.HashMap;
+import java.util.Map;
 
 import envoy.data.Message.MessageStatus;
 
@@ -102,6 +103,35 @@ public class MessageBuilder {
 		return new Message(id, senderID, recipientID, creationDate, text, attachment, status, forwarded);
 	}
 
+	/**
+	 * Creates an instance of {@link GroupMessage} with the previously supplied
+	 * values. <br>
+	 * <b> Sets all member statuses to {@link MessageStatus#WAITING}.</b><br>
+	 * If a mandatory value is not set, a default value will be used
+	 * instead:<br>
+	 * <br>
+	 * <table border="1">
+	 * <tr>
+	 * <td>{@code date}</td>
+	 * <td>{@code new Date()}</td>
+	 * <tr>
+	 * <tr>
+	 * <td>{@code text}</td>
+	 * <td>{@code ""}</td>
+	 * <tr>
+	 * </table>
+	 *
+	 * @param group the {@link Group} that is used to fill the map of member
+	 *              statuses
+	 * @return a new instance of {@link GroupMessage}
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public GroupMessage buildGroupMessage(Group group) {
+		var memberStatuses = new HashMap<Long, Message.MessageStatus>();
+		group.getContacts().forEach(user -> memberStatuses.put(user.getID(), MessageStatus.WAITING));
+		return buildGroupMessage(group, memberStatuses);
+	}
+
 	/**
 	 * Creates an instance of {@link GroupMessage} with the previously supplied
 	 * values. If a mandatory value is not set, a default value will be used
@@ -116,22 +146,17 @@ public class MessageBuilder {
 	 * <td>{@code text}</td>
 	 * <td>{@code ""}</td>
 	 * <tr>
-	 * <tr>
-	 * <td>{@code status}</td>
-	 * <td>{@code MessageStatus.WAITING}</td>
-	 * <tr>
 	 * </table>
 	 *
-	 * @param group the {@link Group} that is used to fill the map of member
-	 *              statuses
+	 * @param group          the {@link Group} that is used to fill the map of
+	 *                       member statuses
+	 * @param memberStatuses the map of all current statuses
 	 * @return a new instance of {@link GroupMessage}
-	 * @since Envoy Common v0.2-alpha
+	 * @since Envoy Common v0.1-beta
 	 */
-	public GroupMessage buildGroupMessage(Group group) {
-		if (group == null) throw new NullPointerException();
+	public GroupMessage buildGroupMessage(Group group, Map<Long, MessageStatus> memberStatuses) {
+		if (group == null || memberStatuses == null) throw new NullPointerException();
 		supplyDefaults();
-		var memberStatuses = new HashMap<Long, Message.MessageStatus>();
-		group.getMemberIDs().forEach(id -> memberStatuses.put(id, MessageStatus.WAITING));
 		return new GroupMessage(id, senderID, recipientID, creationDate, text, attachment, status, forwarded, memberStatuses);
 	}
 
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index d282e29..ca64d0d 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -1,5 +1,11 @@
 package envoy.data;
 
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * Represents a unique user with a unique, numeric ID, a name and a current
  * {@link UserStatus}.<br>
@@ -11,7 +17,16 @@ package envoy.data;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class User extends Contact {
+public final class User extends Contact {
+
+	private UserStatus status;
+
+	/**
+	 * Used to serialize contact list to a maximum depth of one
+	 */
+	private transient boolean serializeContacts = true;
+
+	private static final long serialVersionUID = 1L;
 
 	/**
 	 * This enumeration defines all possible statuses a user can have.
@@ -42,38 +57,50 @@ public class User extends Contact {
 		OFFLINE;
 	}
 
-	private UserStatus status;
-
-	private static final long serialVersionUID = 1L;
-
 	/**
 	 * Initializes a {@link User}. <br>
 	 * The {@link UserStatus} is set to {@link UserStatus#ONLINE}.
+	 * No contacts are initialized.
 	 *
 	 * @param id   unique ID
 	 * @param name user name
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public User(long id, String name) {
-		super(id, name);
+		super(id, name, new HashSet<>());
+		status = UserStatus.ONLINE;
+	}
+
+	/**
+	 * Initializes a {@link User}. <br>
+	 * The {@link UserStatus} is set to {@link UserStatus#ONLINE}.
+	 *
+	 * @param id       unique ID
+	 * @param name     user name
+	 * @param contacts the contacts of this user
+	 * @since Envoy Common v0.2-alpha
+	 */
+	public User(long id, String name, Set<Contact> contacts) {
+		super(id, name, contacts);
 		status = UserStatus.ONLINE;
 	}
 
 	/**
 	 * Initializes a {@link User}.
 	 *
-	 * @param id     unique ID
-	 * @param name   user name
-	 * @param status the status of the user
+	 * @param id       unique ID
+	 * @param name     user name
+	 * @param status   the status of this user
+	 * @param contacts the contacts of this user
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public User(long id, String name, UserStatus status) {
-		super(id, name);
+	public User(long id, String name, UserStatus status, Set<Contact> contacts) {
+		super(id, name, contacts);
 		this.status = status;
 	}
 
 	@Override
-	public String toString() { return String.format("User[id=%d,name=%s,status=%s]", getID(), getName(), status); }
+	public String toString() { return String.format("User[id=%d,name=%s,status=%s,contacts=%s]", getID(), getName(), status, getContacts()); }
 
 	/**
 	 * @return the current status of this user
@@ -86,4 +113,26 @@ public class User extends Contact {
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public void setStatus(UserStatus status) { this.status = status; }
+
+	private void readObject(ObjectInputStream inputStream) throws Exception {
+		inputStream.defaultReadObject();
+		var contacts = Contact.class.getDeclaredField("contacts");
+		contacts.setAccessible(true);
+		contacts.set(this, inputStream.readObject());
+	}
+
+	private void writeObject(ObjectOutputStream outputStream) throws Exception {
+		outputStream.defaultWriteObject();
+		if (serializeContacts) {
+			getContacts().stream().filter(User.class::isInstance).map(User.class::cast).forEach(user -> user.serializeContacts = false);
+			outputStream.writeObject(getContacts());
+		} else outputStream.writeObject(new ArrayList<>());
+	}
+
+	/**
+	 * @param serializeContacts whether the contacts of this {@link User} should be
+	 *                          serialized
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void serializeContacts(boolean serializeContacts) { this.serializeContacts = serializeContacts; }
 }
diff --git a/src/main/java/envoy/event/GroupCreationEvent.java b/src/main/java/envoy/event/GroupCreationEvent.java
index 5b6d365..88c405d 100644
--- a/src/main/java/envoy/event/GroupCreationEvent.java
+++ b/src/main/java/envoy/event/GroupCreationEvent.java
@@ -1,5 +1,10 @@
 package envoy.event;
 
+import java.util.HashSet;
+import java.util.Set;
+
+import envoy.data.User;
+
 /**
  * This event creates a group with the given name.<br>
  * <br>
@@ -12,11 +17,26 @@ package envoy.event;
  */
 public class GroupCreationEvent extends Event<String> {
 
+	private final Set<Long> initialMemberIDs;
+
 	private static final long serialVersionUID = 0L;
 
 	/**
-	 * @param value the name of this group at creation time
+	 * @param value            the name of this group at creation time
+	 * @param initialMemberIDs the IDs of all {@link User}s that should be group
+	 *                         members from the beginning on (excluding the creator
+	 *                         of this group)
 	 * @since Envoy Common v0.1-beta
 	 */
-	public GroupCreationEvent(String value) { super(value); }
+	public GroupCreationEvent(String value, Set<Long> initialMemberIDs) {
+		super(value);
+		this.initialMemberIDs = (initialMemberIDs != null) ? initialMemberIDs : new HashSet<>();
+	}
+
+	/**
+	 * @return the IDs of all {@link User}s that are members from the beginning
+	 *         (excluding the creator of this group)
+	 * @since Envoy Common v0.1-beta
+	 */
+	public Set<Long> getInitialMemberIDs() { return initialMemberIDs; }
 }
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index 24f4ac8..5f6791e 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -36,7 +36,7 @@ public class GroupResizeEvent extends Event<Long> {
 	 */
 	public GroupResizeEvent(User user, Group group, ElementOperation operation) {
 		super(user.getID());
-		if (group.getMemberIDs().contains(user.getID())) {
+		if (group.getContacts().contains(user)) {
 			if (operation.equals(ElementOperation.ADD)) throw new IllegalStateException(
 					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");
 		} else if (operation.equals(ElementOperation.REMOVE))
diff --git a/src/test/java/envoy/data/UserTest.java b/src/test/java/envoy/data/UserTest.java
new file mode 100644
index 0000000..b04134d
--- /dev/null
+++ b/src/test/java/envoy/data/UserTest.java
@@ -0,0 +1,35 @@
+package envoy.data;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.util.Set;
+
+import org.junit.jupiter.api.Test;
+
+import envoy.data.User.UserStatus;
+import envoy.util.SerializationUtils;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>UserTest.java</strong><br>
+ * Created: <strong>31 Mar 2020</strong><br>
+ *
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.1-beta
+ */
+class UserTest {
+
+	@Test
+	void test() throws IOException, ClassNotFoundException {
+		User	user2				= new User(2, "kai");
+		User	user3				= new User(3, "ai");
+		User	user4				= new User(4, "ki", Set.of(user2, user3));
+		User	user5				= new User(5, "ka", Set.of(user2, user3, user4));
+		User	user				= new User(1, "maxi", UserStatus.AWAY, Set.of(user2, user3, user4, user5));
+		var		serializedUser		= SerializationUtils.writeToByteArray(user);
+		var		deserializedUser	= SerializationUtils.read(serializedUser, User.class);
+		assertEquals(user.getContacts(), deserializedUser.getContacts());
+	}
+
+}

From c176dc6e7577cfac007992a3e6c2d140dc30bb08 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Wed, 1 Apr 2020 18:15:41 +0200
Subject: [PATCH 20/33] fixed one "major" spelling error (Id-> ID)

---
 src/main/java/envoy/event/NameChangeEvent.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main/java/envoy/event/NameChangeEvent.java b/src/main/java/envoy/event/NameChangeEvent.java
index 76f6e46..bced039 100644
--- a/src/main/java/envoy/event/NameChangeEvent.java
+++ b/src/main/java/envoy/event/NameChangeEvent.java
@@ -45,7 +45,7 @@ public class NameChangeEvent extends Event<String> {
 	 * @return the ID of the {@link Contact} this event is related to
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public long getId() { return id; }
+	public long getID() { return id; }
 
 	@Override
 	public String toString() { return String.format("NameChangeEvent[id=%d,name=%s]", id, value); }

From 9b413f81ff696751aa60472eb365533281771bbb Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Thu, 2 Apr 2020 09:06:10 +0200
Subject: [PATCH 21/33] Added Junit 5 as dependency

---
 .classpath                            | 4 ++--
 pom.xml                               | 9 ++++++++-
 src/main/java/envoy/data/Contact.java | 2 +-
 src/main/java/envoy/data/User.java    | 3 +--
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/.classpath b/.classpath
index e716709..43b52b8 100644
--- a/.classpath
+++ b/.classpath
@@ -8,9 +8,9 @@
 	</classpathentry>
 	<classpathentry kind="src" output="target/test-classes" path="src/test/java">
 		<attributes>
+			<attribute name="test" value="true"/>
 			<attribute name="optional" value="true"/>
 			<attribute name="maven.pomderived" value="true"/>
-			<attribute name="test" value="true"/>
 		</attributes>
 	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
@@ -21,9 +21,9 @@
 	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
 		<attributes>
+			<attribute name="module" value="true"/>
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/5"/>
 	<classpathentry kind="output" path="target/classes"/>
 </classpath>
diff --git a/pom.xml b/pom.xml
index 98d18f7..aa2ee32 100644
--- a/pom.xml
+++ b/pom.xml
@@ -16,6 +16,13 @@
 		<maven.compiler.target>11</maven.compiler.target>
 	</properties>
 
+	<dependencies>
+		<dependency>
+			<groupId>org.junit.jupiter</groupId>
+			<artifactId>junit-jupiter-engine</artifactId>
+			<version>5.5.2</version>
+		</dependency>
+	</dependencies>
 	<build>
 		<finalName>envoy-common</finalName>
 		<resources>
@@ -23,7 +30,7 @@
 				<directory>src/main/resources</directory>
 			</resource>
 		</resources>
- 		<testSourceDirectory>src/test/java</testSourceDirectory>
+		<testSourceDirectory>src/test/java</testSourceDirectory>
 		<pluginManagement>
 			<plugins>
 				<plugin>
diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index b3b2d03..4de77a0 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -28,7 +28,7 @@ public abstract class Contact implements Serializable {
 	 *
 	 * @param id       the ID of this contact
 	 * @param name     the name of this contact
-	 * @param contacts the {@link Contacts} of this {@link Contact}
+	 * @param contacts the contacts of this {@link Contact}
 	 * @since Envoy Common v0.1-beta
 	 */
 	public Contact(long id, String name, Set<? extends Contact> contacts) {
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index ca64d0d..01b2439 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -2,7 +2,6 @@ package envoy.data;
 
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
-import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -126,7 +125,7 @@ public final class User extends Contact {
 		if (serializeContacts) {
 			getContacts().stream().filter(User.class::isInstance).map(User.class::cast).forEach(user -> user.serializeContacts = false);
 			outputStream.writeObject(getContacts());
-		} else outputStream.writeObject(new ArrayList<>());
+		} else outputStream.writeObject(new HashSet<>());
 	}
 
 	/**

From b2cd3c340cbacc6a0c6c3f1f84dd9e255bbdbc51 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Thu, 2 Apr 2020 19:49:56 +0200
Subject: [PATCH 22/33] fixed minor bug

---
 .../java/envoy/event/contact/ContactOperationEvent.java   | 6 +++---
 .../java/envoy/event/contact/ContactSearchResult.java     | 8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/main/java/envoy/event/contact/ContactOperationEvent.java b/src/main/java/envoy/event/contact/ContactOperationEvent.java
index 59a08cf..6758858 100644
--- a/src/main/java/envoy/event/contact/ContactOperationEvent.java
+++ b/src/main/java/envoy/event/contact/ContactOperationEvent.java
@@ -1,6 +1,6 @@
 package envoy.event.contact;
 
-import envoy.data.User;
+import envoy.data.Contact;
 import envoy.event.ElementOperation;
 import envoy.event.Event;
 
@@ -14,7 +14,7 @@ import envoy.event.Event;
  * @author Maximilian K&auml;fer
  * @since Envoy Common v0.2-alpha
  */
-public class ContactOperationEvent extends Event<User> {
+public class ContactOperationEvent extends Event<Contact> {
 
 	private final ElementOperation operationType;
 
@@ -27,7 +27,7 @@ public class ContactOperationEvent extends Event<User> {
 	 * @param operationType the type of operation to perform
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public ContactOperationEvent(User contact, ElementOperation operationType) {
+	public ContactOperationEvent(Contact contact, ElementOperation operationType) {
 		super(contact);
 		this.operationType = operationType;
 	}
diff --git a/src/main/java/envoy/event/contact/ContactSearchResult.java b/src/main/java/envoy/event/contact/ContactSearchResult.java
index 635d5fd..aed8b12 100644
--- a/src/main/java/envoy/event/contact/ContactSearchResult.java
+++ b/src/main/java/envoy/event/contact/ContactSearchResult.java
@@ -2,11 +2,11 @@ package envoy.event.contact;
 
 import java.util.List;
 
-import envoy.data.User;
+import envoy.data.Contact;
 import envoy.event.Event;
 
 /**
- * Contains a list of {@link User}s for which a search was performed.<br>
+ * Contains a list of {@link Contact}s for which a search was performed.<br>
  * <br>
  * Project: <strong>envoy-common</strong><br>
  * File: <strong>ContactSearchResult.java</strong><br>
@@ -15,7 +15,7 @@ import envoy.event.Event;
  * @author Kai S. K. Engelbart
  * @since Envoy Common v0.2-alpha
  */
-public class ContactSearchResult extends Event<List<User>> {
+public class ContactSearchResult extends Event<List<Contact>> {
 
 	private static final long serialVersionUID = 0L;
 
@@ -25,5 +25,5 @@ public class ContactSearchResult extends Event<List<User>> {
 	 * @param users the users found during the search
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public ContactSearchResult(List<User> users) { super(users); }
+	public ContactSearchResult(List<Contact> users) { super(users); }
 }

From 051705106b3f239d79929ac5ab68291f0fd68d02 Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Thu, 2 Apr 2020 20:32:54 +0200
Subject: [PATCH 23/33] fixed another bug

---
 src/main/java/envoy/event/GroupResizeEvent.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index 5f6791e..c750d7f 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -17,7 +17,7 @@ import envoy.data.User;
  * @author Leon Hofmeister
  * @since Envoy Common v0.1-beta
  */
-public class GroupResizeEvent extends Event<Long> {
+public class GroupResizeEvent extends Event<User> {
 
 	private final long				groupID;
 	private final ElementOperation	operation;
@@ -35,7 +35,7 @@ public class GroupResizeEvent extends Event<Long> {
 	 * @since Envoy Common v0.2-alpha
 	 */
 	public GroupResizeEvent(User user, Group group, ElementOperation operation) {
-		super(user.getID());
+		super(user);
 		if (group.getContacts().contains(user)) {
 			if (operation.equals(ElementOperation.ADD)) throw new IllegalStateException(
 					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");

From cd33006aef007149faf869e4b387e475f6ed6fe9 Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Fri, 10 Apr 2020 13:43:53 +0200
Subject: [PATCH 24/33] Removed checked exception from LoginCredential
 constructor

---
 .classpath                                    |  1 -
 .settings/org.eclipse.wst.common.component    | 49 ++++++++++---------
 src/main/java/envoy/data/GroupMessage.java    |  5 +-
 .../java/envoy/data/LoginCredentials.java     | 12 +++--
 4 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/.classpath b/.classpath
index 43b52b8..2c86875 100644
--- a/.classpath
+++ b/.classpath
@@ -21,7 +21,6 @@
 	</classpathentry>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11">
 		<attributes>
-			<attribute name="module" value="true"/>
 			<attribute name="maven.pomderived" value="true"/>
 		</attributes>
 	</classpathentry>
diff --git a/.settings/org.eclipse.wst.common.component b/.settings/org.eclipse.wst.common.component
index 08f7658..1dda271 100644
--- a/.settings/org.eclipse.wst.common.component
+++ b/.settings/org.eclipse.wst.common.component
@@ -1,22 +1,27 @@
-<?xml version="1.0" encoding="UTF-8"?><project-modules id="moduleCoreId" project-version="1.5.0">
-                    
-    
-    
-    
-    <wb-module deploy-name="envoy-common">
-                                        
-        
-        
-        
-        <wb-resource deploy-path="/" source-path="/src/main/java"/>
-        <wb-resource deploy-path="/" source-path="/src/main/resources"/>
-                                    
-    
-    
-    
-    </wb-module>
-                
-
-
-
-</project-modules>
+<?xml version="1.0" encoding="UTF-8"?><project-modules id="moduleCoreId" project-version="1.5.0">
+                        
+    
+    
+    
+    
+    <wb-module deploy-name="envoy-common">
+                                                
+        
+        
+        
+        
+        <wb-resource deploy-path="/" source-path="/src/main/java"/>
+                
+        <wb-resource deploy-path="/" source-path="/src/main/resources"/>
+                                            
+    
+    
+    
+    
+    </wb-module>
+                    
+
+
+
+
+</project-modules>
diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
index b1c05ce..234c354 100644
--- a/src/main/java/envoy/data/GroupMessage.java
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -27,11 +27,12 @@ public final class GroupMessage extends Message {
 	 *
 	 * @param id             unique ID
 	 * @param senderID       the ID of the user who sends the message
-	 * @param recipientID    the ID of the user who receives the message
+	 * @param groupID        the ID of the group which receives the message
 	 * @param creationDate   the creation date of the message
 	 * @param text           the text content of the message
 	 * @param attachment     the attachment of the message, if present
-	 * @param status         the current {@link MessageStatus} of the message
+	 * @param status         the current {@link Message.MessageStatus} of the
+	 *                       message
 	 * @param forwarded      whether this message was forwarded
 	 * @param memberStatuses a map of all members and their status according to this
 	 *                       {@link GroupMessage}
diff --git a/src/main/java/envoy/data/LoginCredentials.java b/src/main/java/envoy/data/LoginCredentials.java
index 438dd15..e097047 100644
--- a/src/main/java/envoy/data/LoginCredentials.java
+++ b/src/main/java/envoy/data/LoginCredentials.java
@@ -30,16 +30,22 @@ public class LoginCredentials implements Serializable {
 	 * @param password     the password of the user (will be converted to a hash)
 	 * @param registration signifies that these credentials are used for user
 	 *                     registration instead of user login
-	 * @throws NoSuchAlgorithmException if the algorithm used is unknown
 	 * @since Envoy Common v0.2-alpha
 	 */
-	public LoginCredentials(String identifier, char[] password, boolean registration) throws NoSuchAlgorithmException {
+	public LoginCredentials(String identifier, char[] password, boolean registration) {
 		this.identifier		= identifier;
 		passwordHash		= getSha256(toByteArray(password));
 		this.registration	= registration;
 	}
 
-	private byte[] getSha256(byte[] input) throws NoSuchAlgorithmException { return MessageDigest.getInstance("SHA-256").digest(input); }
+	private byte[] getSha256(byte[] input) {
+		try {
+			return MessageDigest.getInstance("SHA-256").digest(input);
+		} catch (NoSuchAlgorithmException e) {
+			// This will never happen
+			throw new RuntimeException(e);
+		}
+	}
 
 	private byte[] toByteArray(char[] chars) {
 		byte[] bytes = new byte[chars.length * 2];

From 373faae63b1920b137d54596adc59e572d86667e Mon Sep 17 00:00:00 2001
From: delvh <dev.lh@web.de>
Date: Fri, 10 Apr 2020 15:42:00 +0200
Subject: [PATCH 25/33] Improved Login security

---
 .../envoy/event/HandshakeRejectionEvent.java  | 29 +++----------------
 src/test/java/envoy/data/UserTest.java        |  1 -
 2 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/src/main/java/envoy/event/HandshakeRejectionEvent.java b/src/main/java/envoy/event/HandshakeRejectionEvent.java
index b6efb38..697eeac 100644
--- a/src/main/java/envoy/event/HandshakeRejectionEvent.java
+++ b/src/main/java/envoy/event/HandshakeRejectionEvent.java
@@ -1,7 +1,5 @@
 package envoy.event;
 
-import envoy.data.LoginCredentials;
-
 /**
  * Signifies to the client that the handshake failed for the attached
  * reason.<br>
@@ -16,33 +14,14 @@ import envoy.data.LoginCredentials;
 public class HandshakeRejectionEvent extends Event<String> {
 
 	/**
-	 * Select this value if a given password hash was incorrect
+	 * Select this value if a given password hash or user was incorrect.
 	 */
-	public static final String WRONG_PASSWORD = "an incorrect password was entered";
+	public static final String WRONG_PASSWORD_OR_USER = "password or user were entered incorrectly";
 
 	/**
-	 * Select this value if a given {@link LoginCredentials} pointed at a client who
-	 * is already online
+	 * Select this value if the handshake could not be completed for some reason.
 	 */
-	public static final String ALREADY_ONLINE = "user is already online";
-
-	/**
-	 * Select this value if a given {@link LoginCredentials} pointed at a client who
-	 * does not exist
-	 */
-	public static final String USER_DOES_NOT_EXIST = "user does not exist";
-
-	/**
-	 * Select this value if a given {@link LoginCredentials} with
-	 * {@link LoginCredentials#isRegistration()}==true points at an already existing
-	 * user
-	 */
-	public static final String USER_EXISTS_ALREADY = "user can not be created as he already exists";
-
-	/**
-	 * Select this value if an unknown error occurred
-	 */
-	public static final String UNKNOWN_REASON = "cause of failure is unknown";
+	public static final String INTERNAL_ERROR = "the process could not be finished as an internal error occurred";
 
 	private static final long serialVersionUID = 0L;
 
diff --git a/src/test/java/envoy/data/UserTest.java b/src/test/java/envoy/data/UserTest.java
index b04134d..4a1688b 100644
--- a/src/test/java/envoy/data/UserTest.java
+++ b/src/test/java/envoy/data/UserTest.java
@@ -31,5 +31,4 @@ class UserTest {
 		var		deserializedUser	= SerializationUtils.read(serializedUser, User.class);
 		assertEquals(user.getContacts(), deserializedUser.getContacts());
 	}
-
 }

From 45e75dba418d5ec697f0b34c6d50ea862b4583b6 Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Sat, 18 Apr 2020 16:36:50 +0200
Subject: [PATCH 26/33] Implemented GroupMessageStatusChangeEvent

---
 .settings/org.eclipse.wst.common.component    | 60 ++++++++++---------
 .../event/GroupMessageStatusChangeEvent.java  | 44 ++++++++++++++
 2 files changed, 77 insertions(+), 27 deletions(-)
 create mode 100644 src/main/java/envoy/event/GroupMessageStatusChangeEvent.java

diff --git a/.settings/org.eclipse.wst.common.component b/.settings/org.eclipse.wst.common.component
index 1dda271..9cb8af1 100644
--- a/.settings/org.eclipse.wst.common.component
+++ b/.settings/org.eclipse.wst.common.component
@@ -1,27 +1,33 @@
-<?xml version="1.0" encoding="UTF-8"?><project-modules id="moduleCoreId" project-version="1.5.0">
-                        
-    
-    
-    
-    
-    <wb-module deploy-name="envoy-common">
-                                                
-        
-        
-        
-        
-        <wb-resource deploy-path="/" source-path="/src/main/java"/>
-                
-        <wb-resource deploy-path="/" source-path="/src/main/resources"/>
-                                            
-    
-    
-    
-    
-    </wb-module>
-                    
-
-
-
-
-</project-modules>
+<?xml version="1.0" encoding="UTF-8"?><project-modules id="moduleCoreId" project-version="1.5.0">
+                            
+    
+    
+    
+    
+    
+    <wb-module deploy-name="envoy-common">
+                                                        
+        
+        
+        
+        
+        
+        <wb-resource deploy-path="/" source-path="/src/main/java"/>
+                        
+        
+        <wb-resource deploy-path="/" source-path="/src/main/resources"/>
+        <wb-resource deploy-path="/" source-path="/src/test/java"/>
+                                                    
+    
+    
+    
+    
+    
+    </wb-module>
+                        
+
+
+
+
+
+</project-modules>
diff --git a/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
new file mode 100644
index 0000000..8e0f3e7
--- /dev/null
+++ b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
@@ -0,0 +1,44 @@
+package envoy.event;
+
+import java.util.Date;
+
+import envoy.data.GroupMessage;
+import envoy.data.Message.MessageStatus;
+
+/**
+ * Project: <strong>envoy-common</strong><br>
+ * File: <strong>GroupMessageStatusChangeEvent.java</strong><br>
+ * Created: <strong>18.04.2020</strong><br>
+ * 
+ * @author Maximilian K&auml;fer
+ * @since Envoy Common v0.1-beta
+ */
+public class GroupMessageStatusChangeEvent extends MessageStatusChangeEvent {
+
+	private final long memberID;
+
+	private static final long serialVersionUID = 0L;
+	
+	/**
+	 * Initializes a {@link GroupMessageStatusChangeEvent}.
+	 * 
+	 * @param id     the ID of the {@link GroupMessage} this event is related to
+	 * @param status the status of this specific members {@link GroupMessage}.
+	 * @param date   the date at which the MessageStatus change occurred for this
+	 *               specific member
+	 * @since Envoy Common v0.1-beta
+	 */
+	public GroupMessageStatusChangeEvent(long id, MessageStatus status, Date date, long memberID) {
+		super(id, status, date);
+		this.memberID = memberID;
+	}
+
+	/**
+	 * @return the memberID which the user who sends this event has
+	 * @since Envoy Common v0.1-beta
+	 */
+	public long getMemberID() { return memberID; }
+
+	@Override
+	public String toString() { return String.format("GroupMessageStatusChangeEvent[meta=%s, memberID=%d]", super.toString(), memberID); }
+}

From 462b524455bac979a0fb7a4029fc549b19e7eba5 Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Mon, 8 Jun 2020 08:39:58 +0200
Subject: [PATCH 27/33] Add missing Javadoc, remove unused resource folder

---
 .settings/org.eclipse.core.resources.prefs    |   1 -
 .settings/org.eclipse.jdt.core.prefs          | 361 ++++++++++++++++++
 .settings/org.eclipse.jdt.ui.prefs            |   2 +
 .settings/org.eclipse.wst.common.component    |  16 +-
 pom.xml                                       |  10 +-
 .../event/GroupMessageStatusChangeEvent.java  |  11 +-
 6 files changed, 381 insertions(+), 20 deletions(-)

diff --git a/.settings/org.eclipse.core.resources.prefs b/.settings/org.eclipse.core.resources.prefs
index 04cfa2c..8bc0e1c 100644
--- a/.settings/org.eclipse.core.resources.prefs
+++ b/.settings/org.eclipse.core.resources.prefs
@@ -1,6 +1,5 @@
 eclipse.preferences.version=1
 encoding//src/main/java=UTF-8
-encoding//src/main/resources=UTF-8
 encoding//src/test/java=UTF-8
 encoding//src/test/resources=UTF-8
 encoding/<project>=UTF-8
diff --git a/.settings/org.eclipse.jdt.core.prefs b/.settings/org.eclipse.jdt.core.prefs
index 6fe4a00..3ef0bd1 100644
--- a/.settings/org.eclipse.jdt.core.prefs
+++ b/.settings/org.eclipse.jdt.core.prefs
@@ -109,3 +109,364 @@ org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning
 org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
 org.eclipse.jdt.core.compiler.release=disabled
 org.eclipse.jdt.core.compiler.source=11
+org.eclipse.jdt.core.formatter.align_assignment_statements_on_columns=true
+org.eclipse.jdt.core.formatter.align_fields_grouping_blank_lines=1
+org.eclipse.jdt.core.formatter.align_type_members_on_columns=true
+org.eclipse.jdt.core.formatter.align_variable_declarations_on_columns=true
+org.eclipse.jdt.core.formatter.align_with_spaces=false
+org.eclipse.jdt.core.formatter.alignment_for_additive_operator=16
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_allocation_expression=16
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_annotation=84
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_enum_constant=16
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_explicit_constructor_call=16
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_method_invocation=80
+org.eclipse.jdt.core.formatter.alignment_for_arguments_in_qualified_allocation_expression=20
+org.eclipse.jdt.core.formatter.alignment_for_assignment=0
+org.eclipse.jdt.core.formatter.alignment_for_bitwise_operator=16
+org.eclipse.jdt.core.formatter.alignment_for_compact_if=16
+org.eclipse.jdt.core.formatter.alignment_for_compact_loops=16
+org.eclipse.jdt.core.formatter.alignment_for_conditional_expression=80
+org.eclipse.jdt.core.formatter.alignment_for_conditional_expression_chain=0
+org.eclipse.jdt.core.formatter.alignment_for_enum_constants=16
+org.eclipse.jdt.core.formatter.alignment_for_expressions_in_array_initializer=16
+org.eclipse.jdt.core.formatter.alignment_for_expressions_in_for_loop_header=0
+org.eclipse.jdt.core.formatter.alignment_for_logical_operator=16
+org.eclipse.jdt.core.formatter.alignment_for_method_declaration=0
+org.eclipse.jdt.core.formatter.alignment_for_module_statements=16
+org.eclipse.jdt.core.formatter.alignment_for_multiple_fields=16
+org.eclipse.jdt.core.formatter.alignment_for_multiplicative_operator=16
+org.eclipse.jdt.core.formatter.alignment_for_parameterized_type_references=0
+org.eclipse.jdt.core.formatter.alignment_for_parameters_in_constructor_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_parameters_in_method_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_relational_operator=0
+org.eclipse.jdt.core.formatter.alignment_for_resources_in_try=80
+org.eclipse.jdt.core.formatter.alignment_for_selector_in_method_invocation=84
+org.eclipse.jdt.core.formatter.alignment_for_shift_operator=0
+org.eclipse.jdt.core.formatter.alignment_for_string_concatenation=16
+org.eclipse.jdt.core.formatter.alignment_for_superclass_in_type_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_superinterfaces_in_enum_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_superinterfaces_in_type_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_throws_clause_in_constructor_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_throws_clause_in_method_declaration=16
+org.eclipse.jdt.core.formatter.alignment_for_type_arguments=0
+org.eclipse.jdt.core.formatter.alignment_for_type_parameters=0
+org.eclipse.jdt.core.formatter.alignment_for_union_type_in_multicatch=16
+org.eclipse.jdt.core.formatter.blank_lines_after_imports=1
+org.eclipse.jdt.core.formatter.blank_lines_after_last_class_body_declaration=0
+org.eclipse.jdt.core.formatter.blank_lines_after_package=1
+org.eclipse.jdt.core.formatter.blank_lines_before_abstract_method=1
+org.eclipse.jdt.core.formatter.blank_lines_before_field=0
+org.eclipse.jdt.core.formatter.blank_lines_before_first_class_body_declaration=1
+org.eclipse.jdt.core.formatter.blank_lines_before_imports=1
+org.eclipse.jdt.core.formatter.blank_lines_before_member_type=1
+org.eclipse.jdt.core.formatter.blank_lines_before_method=1
+org.eclipse.jdt.core.formatter.blank_lines_before_new_chunk=1
+org.eclipse.jdt.core.formatter.blank_lines_before_package=0
+org.eclipse.jdt.core.formatter.blank_lines_between_import_groups=1
+org.eclipse.jdt.core.formatter.blank_lines_between_statement_group_in_switch=0
+org.eclipse.jdt.core.formatter.blank_lines_between_type_declarations=1
+org.eclipse.jdt.core.formatter.brace_position_for_annotation_type_declaration=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_anonymous_type_declaration=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_array_initializer=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_block=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_block_in_case=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_constructor_declaration=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_enum_constant=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_enum_declaration=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_lambda_body=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_method_declaration=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_switch=end_of_line
+org.eclipse.jdt.core.formatter.brace_position_for_type_declaration=end_of_line
+org.eclipse.jdt.core.formatter.comment.align_tags_descriptions_grouped=true
+org.eclipse.jdt.core.formatter.comment.align_tags_names_descriptions=false
+org.eclipse.jdt.core.formatter.comment.clear_blank_lines_in_block_comment=true
+org.eclipse.jdt.core.formatter.comment.clear_blank_lines_in_javadoc_comment=false
+org.eclipse.jdt.core.formatter.comment.count_line_length_from_starting_position=true
+org.eclipse.jdt.core.formatter.comment.format_block_comments=true
+org.eclipse.jdt.core.formatter.comment.format_header=true
+org.eclipse.jdt.core.formatter.comment.format_html=true
+org.eclipse.jdt.core.formatter.comment.format_javadoc_comments=true
+org.eclipse.jdt.core.formatter.comment.format_line_comments=true
+org.eclipse.jdt.core.formatter.comment.format_source_code=true
+org.eclipse.jdt.core.formatter.comment.indent_parameter_description=false
+org.eclipse.jdt.core.formatter.comment.indent_root_tags=false
+org.eclipse.jdt.core.formatter.comment.indent_tag_description=false
+org.eclipse.jdt.core.formatter.comment.insert_new_line_before_root_tags=insert
+org.eclipse.jdt.core.formatter.comment.insert_new_line_between_different_tags=do not insert
+org.eclipse.jdt.core.formatter.comment.insert_new_line_for_parameter=do not insert
+org.eclipse.jdt.core.formatter.comment.line_length=80
+org.eclipse.jdt.core.formatter.comment.new_lines_at_block_boundaries=true
+org.eclipse.jdt.core.formatter.comment.new_lines_at_javadoc_boundaries=true
+org.eclipse.jdt.core.formatter.comment.preserve_white_space_between_code_and_line_comments=false
+org.eclipse.jdt.core.formatter.compact_else_if=true
+org.eclipse.jdt.core.formatter.continuation_indentation=2
+org.eclipse.jdt.core.formatter.continuation_indentation_for_array_initializer=2
+org.eclipse.jdt.core.formatter.disabling_tag=@formatter\:off
+org.eclipse.jdt.core.formatter.enabling_tag=@formatter\:on
+org.eclipse.jdt.core.formatter.format_guardian_clause_on_one_line=true
+org.eclipse.jdt.core.formatter.format_line_comment_starting_on_first_column=true
+org.eclipse.jdt.core.formatter.indent_body_declarations_compare_to_annotation_declaration_header=true
+org.eclipse.jdt.core.formatter.indent_body_declarations_compare_to_enum_constant_header=true
+org.eclipse.jdt.core.formatter.indent_body_declarations_compare_to_enum_declaration_header=true
+org.eclipse.jdt.core.formatter.indent_body_declarations_compare_to_type_header=true
+org.eclipse.jdt.core.formatter.indent_breaks_compare_to_cases=true
+org.eclipse.jdt.core.formatter.indent_empty_lines=false
+org.eclipse.jdt.core.formatter.indent_statements_compare_to_block=true
+org.eclipse.jdt.core.formatter.indent_statements_compare_to_body=true
+org.eclipse.jdt.core.formatter.indent_switchstatements_compare_to_cases=true
+org.eclipse.jdt.core.formatter.indent_switchstatements_compare_to_switch=true
+org.eclipse.jdt.core.formatter.indentation.size=4
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_enum_constant=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_field=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_local_variable=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_method=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_package=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_parameter=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_annotation_on_type=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_label=insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_opening_brace_in_array_initializer=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_after_type_annotation=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_at_end_of_file_if_missing=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_before_catch_in_try_statement=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_before_closing_brace_in_array_initializer=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_before_else_in_if_statement=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_before_finally_in_try_statement=do not insert
+org.eclipse.jdt.core.formatter.insert_new_line_before_while_in_do_statement=do not insert
+org.eclipse.jdt.core.formatter.insert_space_after_additive_operator=insert
+org.eclipse.jdt.core.formatter.insert_space_after_and_in_type_parameter=insert
+org.eclipse.jdt.core.formatter.insert_space_after_arrow_in_switch_case=insert
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+org.eclipse.jdt.core.formatter.insert_space_before_colon_in_for=insert
+org.eclipse.jdt.core.formatter.insert_space_before_colon_in_labeled_statement=do not insert
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+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_method_invocation_arguments=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_multiple_field_declarations=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_multiple_local_declarations=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_parameterized_type_reference=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_superinterfaces=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_comma_in_switch_case_expressions=do not insert
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+org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_enum_constant=do not insert
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+org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_parenthesized_expression=do not insert
+org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_switch=insert
+org.eclipse.jdt.core.formatter.insert_space_before_opening_paren_in_synchronized=insert
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+org.eclipse.jdt.core.formatter.insert_space_before_relational_operator=insert
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+org.eclipse.jdt.core.formatter.insert_space_between_empty_braces_in_array_initializer=do not insert
+org.eclipse.jdt.core.formatter.insert_space_between_empty_brackets_in_array_allocation_expression=do not insert
+org.eclipse.jdt.core.formatter.insert_space_between_empty_parens_in_annotation_type_member_declaration=do not insert
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+org.eclipse.jdt.core.formatter.insert_space_between_empty_parens_in_enum_constant=do not insert
+org.eclipse.jdt.core.formatter.insert_space_between_empty_parens_in_method_declaration=do not insert
+org.eclipse.jdt.core.formatter.insert_space_between_empty_parens_in_method_invocation=do not insert
+org.eclipse.jdt.core.formatter.join_lines_in_comments=false
+org.eclipse.jdt.core.formatter.join_wrapped_lines=true
+org.eclipse.jdt.core.formatter.keep_annotation_declaration_on_one_line=one_line_if_single_item
+org.eclipse.jdt.core.formatter.keep_anonymous_type_declaration_on_one_line=one_line_never
+org.eclipse.jdt.core.formatter.keep_code_block_on_one_line=one_line_if_empty
+org.eclipse.jdt.core.formatter.keep_else_statement_on_same_line=true
+org.eclipse.jdt.core.formatter.keep_empty_array_initializer_on_one_line=false
+org.eclipse.jdt.core.formatter.keep_enum_constant_declaration_on_one_line=one_line_never
+org.eclipse.jdt.core.formatter.keep_enum_declaration_on_one_line=one_line_never
+org.eclipse.jdt.core.formatter.keep_if_then_body_block_on_one_line=one_line_if_single_item
+org.eclipse.jdt.core.formatter.keep_imple_if_on_one_line=false
+org.eclipse.jdt.core.formatter.keep_lambda_body_block_on_one_line=one_line_always
+org.eclipse.jdt.core.formatter.keep_loop_body_block_on_one_line=one_line_if_empty
+org.eclipse.jdt.core.formatter.keep_method_body_on_one_line=one_line_if_single_item
+org.eclipse.jdt.core.formatter.keep_simple_do_while_body_on_same_line=false
+org.eclipse.jdt.core.formatter.keep_simple_for_body_on_same_line=false
+org.eclipse.jdt.core.formatter.keep_simple_getter_setter_on_one_line=true
+org.eclipse.jdt.core.formatter.keep_simple_while_body_on_same_line=false
+org.eclipse.jdt.core.formatter.keep_then_statement_on_same_line=true
+org.eclipse.jdt.core.formatter.keep_type_declaration_on_one_line=one_line_never
+org.eclipse.jdt.core.formatter.lineSplit=150
+org.eclipse.jdt.core.formatter.never_indent_block_comments_on_first_column=false
+org.eclipse.jdt.core.formatter.never_indent_line_comments_on_first_column=false
+org.eclipse.jdt.core.formatter.number_of_blank_lines_after_code_block=0
+org.eclipse.jdt.core.formatter.number_of_blank_lines_at_beginning_of_code_block=0
+org.eclipse.jdt.core.formatter.number_of_blank_lines_at_beginning_of_method_body=0
+org.eclipse.jdt.core.formatter.number_of_blank_lines_at_end_of_code_block=0
+org.eclipse.jdt.core.formatter.number_of_blank_lines_at_end_of_method_body=0
+org.eclipse.jdt.core.formatter.number_of_blank_lines_before_code_block=0
+org.eclipse.jdt.core.formatter.number_of_empty_lines_to_preserve=1
+org.eclipse.jdt.core.formatter.parentheses_positions_in_annotation=separate_lines_if_wrapped
+org.eclipse.jdt.core.formatter.parentheses_positions_in_catch_clause=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_enum_constant_declaration=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_for_statment=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_if_while_statement=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_lambda_declaration=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_method_delcaration=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_method_invocation=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_switch_statement=common_lines
+org.eclipse.jdt.core.formatter.parentheses_positions_in_try_clause=common_lines
+org.eclipse.jdt.core.formatter.put_empty_statement_on_new_line=true
+org.eclipse.jdt.core.formatter.tabulation.char=tab
+org.eclipse.jdt.core.formatter.tabulation.size=4
+org.eclipse.jdt.core.formatter.text_block_indentation=0
+org.eclipse.jdt.core.formatter.use_on_off_tags=false
+org.eclipse.jdt.core.formatter.use_tabs_only_for_leading_indentations=false
+org.eclipse.jdt.core.formatter.wrap_before_additive_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_assignment_operator=false
+org.eclipse.jdt.core.formatter.wrap_before_bitwise_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_conditional_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_logical_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_multiplicative_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_or_operator_multicatch=true
+org.eclipse.jdt.core.formatter.wrap_before_relational_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_shift_operator=true
+org.eclipse.jdt.core.formatter.wrap_before_string_concatenation=true
+org.eclipse.jdt.core.formatter.wrap_outer_expressions_when_nested=true
+org.eclipse.jdt.core.javaFormatter=org.eclipse.jdt.core.defaultJavaFormatter
diff --git a/.settings/org.eclipse.jdt.ui.prefs b/.settings/org.eclipse.jdt.ui.prefs
index 1a7acd7..035cdab 100644
--- a/.settings/org.eclipse.jdt.ui.prefs
+++ b/.settings/org.eclipse.jdt.ui.prefs
@@ -1,3 +1,5 @@
 eclipse.preferences.version=1
+formatter_profile=_KSKE
+formatter_settings_version=18
 org.eclipse.jdt.ui.javadoc=true
 org.eclipse.jdt.ui.text.custom_code_templates=<?xml version\="1.0" encoding\="UTF-8" standalone\="no"?><templates><template autoinsert\="false" context\="gettercomment_context" deleted\="false" description\="Comment for getter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.gettercomment" name\="gettercomment">/**\r\n * @return the ${bare_field_name}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="settercomment_context" deleted\="false" description\="Comment for setter method" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.settercomment" name\="settercomment">/**\r\n * @param ${param} the ${bare_field_name} to set\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="constructorcomment_context" deleted\="false" description\="Comment for created constructors" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorcomment" name\="constructorcomment">/**\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="filecomment_context" deleted\="false" description\="Comment for created Java files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.filecomment" name\="filecomment"/><template autoinsert\="false" context\="typecomment_context" deleted\="false" description\="Comment for created types" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.typecomment" name\="typecomment">/**\r\n * Project\: &lt;strong&gt;${project_name}&lt;/strong&gt;&lt;br&gt;\r\n * File\: &lt;strong&gt;${file_name}&lt;/strong&gt;&lt;br&gt;\r\n * Created\: &lt;strong&gt;${date}&lt;/strong&gt;&lt;br&gt;\r\n * \r\n * @author ${user}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="fieldcomment_context" deleted\="false" description\="Comment for fields" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.fieldcomment" name\="fieldcomment"/><template autoinsert\="false" context\="methodcomment_context" deleted\="false" description\="Comment for non-overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodcomment" name\="methodcomment">/**\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="modulecomment_context" deleted\="false" description\="Comment for modules" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.modulecomment" name\="modulecomment">/**\r\n * @author ${user}\r\n *\r\n * ${tags}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="false" context\="overridecomment_context" deleted\="false" description\="Comment for overriding methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.overridecomment" name\="overridecomment">/**\r\n * {@inheritDoc}\r\n */</template><template autoinsert\="false" context\="delegatecomment_context" deleted\="false" description\="Comment for delegate methods" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.delegatecomment" name\="delegatecomment">/**\r\n * ${tags}\r\n * ${see_to_target}\r\n * @since Envoy Common v0.1-beta\r\n */</template><template autoinsert\="true" context\="newtype_context" deleted\="false" description\="Newly created files" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.newtype" name\="newtype">${filecomment}\r\n${package_declaration}\r\n\r\n${typecomment}\r\n${type_declaration}</template><template autoinsert\="true" context\="classbody_context" deleted\="false" description\="Code in new class type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.classbody" name\="classbody">\r\n</template><template autoinsert\="true" context\="interfacebody_context" deleted\="false" description\="Code in new interface type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.interfacebody" name\="interfacebody">\r\n</template><template autoinsert\="true" context\="enumbody_context" deleted\="false" description\="Code in new enum type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.enumbody" name\="enumbody">\r\n</template><template autoinsert\="true" context\="annotationbody_context" deleted\="false" description\="Code in new annotation type bodies" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.annotationbody" name\="annotationbody">\r\n</template><template autoinsert\="false" context\="catchblock_context" deleted\="false" description\="Code in new catch blocks" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.catchblock" name\="catchblock">${exception_var}.printStackTrace();</template><template autoinsert\="false" context\="methodbody_context" deleted\="false" description\="Code in created method stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.methodbody" name\="methodbody">${body_statement}</template><template autoinsert\="false" context\="constructorbody_context" deleted\="false" description\="Code in created constructor stubs" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.constructorbody" name\="constructorbody">${body_statement}</template><template autoinsert\="true" context\="getterbody_context" deleted\="false" description\="Code in created getters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.getterbody" name\="getterbody">return ${field};</template><template autoinsert\="true" context\="setterbody_context" deleted\="false" description\="Code in created setters" enabled\="true" id\="org.eclipse.jdt.ui.text.codetemplates.setterbody" name\="setterbody">${field} \= ${param};</template></templates>
diff --git a/.settings/org.eclipse.wst.common.component b/.settings/org.eclipse.wst.common.component
index 9cb8af1..44aa2b3 100644
--- a/.settings/org.eclipse.wst.common.component
+++ b/.settings/org.eclipse.wst.common.component
@@ -1,30 +1,30 @@
 <?xml version="1.0" encoding="UTF-8"?><project-modules id="moduleCoreId" project-version="1.5.0">
-                            
+                                
+    
     
     
     
     
     
     <wb-module deploy-name="envoy-common">
-                                                        
+                                                                
+        
         
         
         
         
         
         <wb-resource deploy-path="/" source-path="/src/main/java"/>
-                        
-        
-        <wb-resource deploy-path="/" source-path="/src/main/resources"/>
-        <wb-resource deploy-path="/" source-path="/src/test/java"/>
-                                                    
+                                                            
+    
     
     
     
     
     
     </wb-module>
-                        
+                            
+
 
 
 
diff --git a/pom.xml b/pom.xml
index aa2ee32..0060e9a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -25,12 +25,10 @@
 	</dependencies>
 	<build>
 		<finalName>envoy-common</finalName>
-		<resources>
-			<resource>
-				<directory>src/main/resources</directory>
-			</resource>
-		</resources>
-		<testSourceDirectory>src/test/java</testSourceDirectory>
+		
+		<!-- Disable resource folder -->
+		<resources />
+		
 		<pluginManagement>
 			<plugins>
 				<plugin>
diff --git a/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
index 8e0f3e7..81f6a15 100644
--- a/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
+++ b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
@@ -18,14 +18,15 @@ public class GroupMessageStatusChangeEvent extends MessageStatusChangeEvent {
 	private final long memberID;
 
 	private static final long serialVersionUID = 0L;
-	
+
 	/**
 	 * Initializes a {@link GroupMessageStatusChangeEvent}.
 	 * 
-	 * @param id     the ID of the {@link GroupMessage} this event is related to
-	 * @param status the status of this specific members {@link GroupMessage}.
-	 * @param date   the date at which the MessageStatus change occurred for this
-	 *               specific member
+	 * @param id       the ID of the {@link GroupMessage} this event is related to
+	 * @param status   the status of this specific members {@link GroupMessage}
+	 * @param date     the date at which the MessageStatus change occurred for
+	 *                 this specific member
+	 * @param memberID the ID of the group member that caused the status change
 	 * @since Envoy Common v0.1-beta
 	 */
 	public GroupMessageStatusChangeEvent(long id, MessageStatus status, Date date, long memberID) {

From c67a11f008968a12de104944ea456d0758f0d4fb Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Wed, 10 Jun 2020 09:03:22 +0200
Subject: [PATCH 28/33] Remove ContactDeletionEvent in favor of
 ContactOperationEvent

---
 .../event/contact/ContactDeletionEvent.java   | 26 -------------------
 1 file changed, 26 deletions(-)
 delete mode 100644 src/main/java/envoy/event/contact/ContactDeletionEvent.java

diff --git a/src/main/java/envoy/event/contact/ContactDeletionEvent.java b/src/main/java/envoy/event/contact/ContactDeletionEvent.java
deleted file mode 100644
index 79c13d1..0000000
--- a/src/main/java/envoy/event/contact/ContactDeletionEvent.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package envoy.event.contact;
-
-import envoy.data.Contact;
-import envoy.event.Event;
-
-/**
- * This event is sent if a {@link Contact} has been deleted/ has decided to
- * delete himself.<br>
- * <br>
- * Project: <strong>envoy-common</strong><br>
- * File: <strong>ContactDeletionEvent.java</strong><br>
- * Created: <strong>28 Mar 2020</strong><br>
- *
- * @author Leon Hofmeister
- * @since Envoy Common v0.1-beta
- */
-public class ContactDeletionEvent extends Event<Long> {
-
-	private static final long serialVersionUID = 0L;
-
-	/**
-	 * @param value the id of the {@link Contact} being deleted
-	 * @since Envoy Common v0.1-beta
-	 */
-	protected ContactDeletionEvent(Long value) { super(value); }
-}

From 51e148e2ec3af73a88ce0b06f9dadb09e92df4c3 Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Thu, 11 Jun 2020 11:05:38 +0200
Subject: [PATCH 29/33] Add Javadoc for hashCode and equals methods of Contact

---
 src/main/java/envoy/data/Contact.java | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/main/java/envoy/data/Contact.java b/src/main/java/envoy/data/Contact.java
index 4de77a0..9a5fd0a 100644
--- a/src/main/java/envoy/data/Contact.java
+++ b/src/main/java/envoy/data/Contact.java
@@ -62,13 +62,19 @@ public abstract class Contact implements Serializable {
 	public String toString() { return String.format("Contact[id=%d,name=%s, contacts=%s]", id, name, contacts); }
 
 	/**
-	 * {@inheritDoc}
+	 * Provides a hash code based on the ID of this contact.
+	 * 
+	 * @since Envoy Common v0.1-beta
 	 */
 	@Override
 	public int hashCode() { return Objects.hash(id); }
 
 	/**
-	 * {@inheritDoc}
+	 * Tests equality to another object. If that object is a contact as well,
+	 * equality is determined by the ID.
+	 * 
+	 * @param obj the object to test for equality to this contact
+	 * @return {code true} if both objects are contacts and have identical IDs
 	 */
 	@Override
 	public boolean equals(Object obj) {

From b92a1630a1f83efea27c28ca864bda777a207fe7 Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Thu, 11 Jun 2020 11:24:00 +0200
Subject: [PATCH 30/33] Add config initialization with a map of config items

---
 src/main/java/envoy/data/Config.java | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/main/java/envoy/data/Config.java b/src/main/java/envoy/data/Config.java
index c281d0e..bcff68c 100644
--- a/src/main/java/envoy/data/Config.java
+++ b/src/main/java/envoy/data/Config.java
@@ -61,6 +61,14 @@ public class Config {
 				} else throw new EnvoyException("Malformed command line argument at position " + i);
 	}
 
+	/**
+	 * Initializes config items from a map.
+	 * 
+	 * @param items the items to include in this config
+	 * @since Envoy Common v0.1-beta
+	 */
+	public void load(Map<String, ConfigItem<?>> items) { this.items.putAll(items); }
+
 	/**
 	 * @return {@code true} if all mandatory config items are initialized
 	 * @since Envoy Common v0.1-beta

From 1026ca4f8d8cd639ff9f190c0bd09f8d339f8df5 Mon Sep 17 00:00:00 2001
From: kske <kai@kske.dev>
Date: Thu, 11 Jun 2020 12:14:20 +0200
Subject: [PATCH 31/33] Immediately flush the console log

---
 src/main/java/envoy/util/EnvoyLog.java | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/main/java/envoy/util/EnvoyLog.java b/src/main/java/envoy/util/EnvoyLog.java
index deba66d..a797d75 100644
--- a/src/main/java/envoy/util/EnvoyLog.java
+++ b/src/main/java/envoy/util/EnvoyLog.java
@@ -60,7 +60,17 @@ public class EnvoyLog {
 		} catch (SecurityException | IOException e) {
 			e.printStackTrace();
 		}
-		consoleHandler = new StreamHandler(System.out, formatter);
+		consoleHandler = new StreamHandler(System.out, formatter) {
+
+			/**
+			 * {@inheritDoc}
+			 */
+			@Override
+			public synchronized void publish(LogRecord record) {
+				super.publish(record);
+				flush();
+			}
+		};
 		consoleHandler.setLevel((Level) config.get("consoleLevelBarrier").get());
 		consoleHandler.setFormatter(formatter);
 

From 439e274c3735139925f89a0b959e1e8218ce3fd7 Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 11 Jun 2020 13:55:38 +0200
Subject: [PATCH 32/33] Apply suggestions from code review

Co-authored-by: CyB3RC0nN0R <CyB3RC0nN0R@users.noreply.github.com>
---
 src/main/java/envoy/event/GroupMessageStatusChangeEvent.java | 3 ++-
 src/main/java/envoy/event/GroupResizeEvent.java              | 4 ++--
 src/main/java/envoy/event/HandshakeRejectionEvent.java       | 4 ++--
 src/main/java/envoy/util/EnvoyLog.java                       | 3 ---
 4 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
index 81f6a15..b02f980 100644
--- a/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
+++ b/src/main/java/envoy/event/GroupMessageStatusChangeEvent.java
@@ -41,5 +41,6 @@ public class GroupMessageStatusChangeEvent extends MessageStatusChangeEvent {
 	public long getMemberID() { return memberID; }
 
 	@Override
-	public String toString() { return String.format("GroupMessageStatusChangeEvent[meta=%s, memberID=%d]", super.toString(), memberID); }
+	public String toString() { return String.format("GroupMessageStatusChangeEvent[meta=%s,memberID=%d]", super.toString(), memberID); }
+
 }
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index c750d7f..a0d8d40 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -37,10 +37,10 @@ public class GroupResizeEvent extends Event<User> {
 	public GroupResizeEvent(User user, Group group, ElementOperation operation) {
 		super(user);
 		if (group.getContacts().contains(user)) {
-			if (operation.equals(ElementOperation.ADD)) throw new IllegalStateException(
+			if (operation.equals(ElementOperation.ADD)) throw new IllegalArgumentException(
 					"Cannot add " + user + " to group " + group.getID() + " because he is already a member of this group");
 		} else if (operation.equals(ElementOperation.REMOVE))
-			throw new IllegalStateException("Cannot remove " + user + " from group " + group.getID() + " because he is no part of this group");
+			throw new IllegalArgumentException("Cannot remove " + user + " from group " + group.getID() + " because he is no part of this group");
 		groupID			= group.getID();
 		this.operation	= operation;
 	}
diff --git a/src/main/java/envoy/event/HandshakeRejectionEvent.java b/src/main/java/envoy/event/HandshakeRejectionEvent.java
index 697eeac..fea1058 100644
--- a/src/main/java/envoy/event/HandshakeRejectionEvent.java
+++ b/src/main/java/envoy/event/HandshakeRejectionEvent.java
@@ -16,12 +16,12 @@ public class HandshakeRejectionEvent extends Event<String> {
 	/**
 	 * Select this value if a given password hash or user was incorrect.
 	 */
-	public static final String WRONG_PASSWORD_OR_USER = "password or user were entered incorrectly";
+	public static final String WRONG_PASSWORD_OR_USER = "Incorrect user name or password.";
 
 	/**
 	 * Select this value if the handshake could not be completed for some reason.
 	 */
-	public static final String INTERNAL_ERROR = "the process could not be finished as an internal error occurred";
+	public static final String INTERNAL_ERROR = "An internal error occured.";
 
 	private static final long serialVersionUID = 0L;
 
diff --git a/src/main/java/envoy/util/EnvoyLog.java b/src/main/java/envoy/util/EnvoyLog.java
index a797d75..f3bc919 100644
--- a/src/main/java/envoy/util/EnvoyLog.java
+++ b/src/main/java/envoy/util/EnvoyLog.java
@@ -62,9 +62,6 @@ public class EnvoyLog {
 		}
 		consoleHandler = new StreamHandler(System.out, formatter) {
 
-			/**
-			 * {@inheritDoc}
-			 */
 			@Override
 			public synchronized void publish(LogRecord record) {
 				super.publish(record);

From ad3f29859390ce425037e7c6f702d218010f19fa Mon Sep 17 00:00:00 2001
From: DieGurke <55625494+DieGurke@users.noreply.github.com>
Date: Thu, 11 Jun 2020 14:00:07 +0200
Subject: [PATCH 33/33] Resolved requests

---
 src/main/java/envoy/data/Group.java             | 1 -
 src/main/java/envoy/data/GroupMessage.java      | 1 -
 src/main/java/envoy/data/User.java              | 2 +-
 src/main/java/envoy/event/ElementOperation.java | 6 ++++--
 src/main/java/envoy/event/GroupResizeEvent.java | 2 +-
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/main/java/envoy/data/Group.java b/src/main/java/envoy/data/Group.java
index bec17be..4eb6b02 100644
--- a/src/main/java/envoy/data/Group.java
+++ b/src/main/java/envoy/data/Group.java
@@ -47,7 +47,6 @@ public final class Group extends Contact {
 		outputStream.defaultWriteObject();
 		getContacts().forEach(user -> user.serializeContacts(false));
 		outputStream.writeObject(getContacts());
-
 	}
 
 	@SuppressWarnings("unchecked")
diff --git a/src/main/java/envoy/data/GroupMessage.java b/src/main/java/envoy/data/GroupMessage.java
index 234c354..a2f8488 100644
--- a/src/main/java/envoy/data/GroupMessage.java
+++ b/src/main/java/envoy/data/GroupMessage.java
@@ -55,7 +55,6 @@ public final class GroupMessage extends Message {
 			case RECEIVED:
 				setReceivedDate(new Date());
 				break;
-
 			case READ:
 				setReadDate(new Date());
 				break;
diff --git a/src/main/java/envoy/data/User.java b/src/main/java/envoy/data/User.java
index 01b2439..7751ce3 100644
--- a/src/main/java/envoy/data/User.java
+++ b/src/main/java/envoy/data/User.java
@@ -21,7 +21,7 @@ public final class User extends Contact {
 	private UserStatus status;
 
 	/**
-	 * Used to serialize contact list to a maximum depth of one
+	 * Used to serialize contact list to a maximum depth of one.
 	 */
 	private transient boolean serializeContacts = true;
 
diff --git a/src/main/java/envoy/event/ElementOperation.java b/src/main/java/envoy/event/ElementOperation.java
index e0ed0df..b7d4c10 100644
--- a/src/main/java/envoy/event/ElementOperation.java
+++ b/src/main/java/envoy/event/ElementOperation.java
@@ -13,14 +13,16 @@ package envoy.event;
  * @since Envoy Common v0.1-beta
  */
 public enum ElementOperation {
+
 	/**
 	 * Select this element, if the given element should be added to the given
-	 * container
+	 * container.
 	 */
 	ADD,
+
 	/**
 	 * Select this element, if the given element should be removed from the given
-	 * container
+	 * container.
 	 */
 	REMOVE
 }
diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index a0d8d40..46952d5 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -8,7 +8,7 @@ import envoy.data.User;
  * This event is used to communicate changes in the group size between client
  * and server.<br>
  * Possible actions are adding or removing certain {@link User}s to or from a
- * certain {@link Group}
+ * certain {@link Group}.
  * <br>
  * Project: <strong>envoy-common</strong><br>
  * File: <strong>GroupResizeEvent.java</strong><br>