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

@@ -24,5 +24,6 @@
 			<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>

pom.xml

@@ -23,6 +23,7 @@
 				<directory>src/main/resources</directory>
 			</resource>
 		</resources>
+ 		<testSourceDirectory>src/test/java</testSourceDirectory>
 		<pluginManagement>
 			<plugins>
 				<plugin>

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>
@@ -17,6 +18,7 @@ import java.util.Objects;
 public abstract class Contact implements Serializable {
 
 	private final long								id;
+	private final transient Set<? extends Contact>	contacts;
 	private String									name;
 
 	private static final long serialVersionUID = 0L;
@@ -26,11 +28,13 @@ 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}
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Contact(long id, String 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; }
 }

src/main/java/envoy/data/Contacts.java

@@ -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; }
-}

src/main/java/envoy/data/Group.java

@@ -1,8 +1,9 @@
 package envoy.data;
 
-import java.util.ArrayList;
+import java.io.ObjectInputStream;
-import java.util.List;
+import java.io.ObjectOutputStream;
-import java.util.StringJoiner;
+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 {
+public final class Group extends Contact {
-
-	// TODO add admins
-	private final List<Long> memberIDs;
 
 	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 members all members that should be preinitialized
 	 * @since Envoy Common v0.1-beta
 	 */
-	public Group(long id, String name, List<Long> memberIDs) {
+	public Group(long id, String name, Set<User> members) { super(id, name, members); }
-		super(id, name);
+
-		this.memberIDs = memberIDs;
+	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 {
-	 * @return the IDs of all members of this group
+		outputStream.defaultWriteObject();
-	 * @since Envoy Common v0.1-beta
+		getContacts().forEach(user -> user.serializeContacts(false));
-	 */
+		outputStream.writeObject(getContacts());
-	public List<Long> getMemberIDs() { return memberIDs; }
 
-	/**
+	}
-	 * {@inheritDoc}
+
-	 */
+	@SuppressWarnings("unchecked")
 	@Override
-	public String toString() {
+	public Set<User> getContacts() { return (Set<User>) super.getContacts(); }
-		var joiner = new StringJoiner(",", "Group[id=", "]");
-		joiner.add("id=" + getID());
-		joiner.add("name=" + getName());
-		joiner.add("members=" + getMemberIDs().size());
-		return joiner.toString();
-	}
 }

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
+	 * @param group          the {@link Group} that is used to fill the map of
-	 *              statuses
+	 *                       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) {
+	public GroupMessage buildGroupMessage(Group group, Map<Long, MessageStatus> memberStatuses) {
-		if (group == null) throw new NullPointerException();
+		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);
 	}
 

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.
@@ -42,9 +57,19 @@ public class User extends Contact {
 		OFFLINE;
 	}
 
-	private UserStatus status;
+	/**
-
+	 * Initializes a {@link User}. <br>
-	private static final long serialVersionUID = 1L;
+	 * 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, new HashSet<>());
+		status = UserStatus.ONLINE;
+	}
 
 	/**
 	 * Initializes a {@link User}. <br>
@@ -52,10 +77,11 @@ public class User extends Contact {
 	 *
 	 * @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) {
+	public User(long id, String name, Set<Contact> contacts) {
-		super(id, name);
+		super(id, name, contacts);
 		status = UserStatus.ONLINE;
 	}
 
@@ -64,16 +90,17 @@ public class User extends Contact {
 	 *
 	 * @param id       unique ID
 	 * @param name     user name
-	 * @param status the status of the user
+	 * @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) {
+	public User(long id, String name, UserStatus status, Set<Contact> contacts) {
-		super(id, name);
+		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; }
 }

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 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; }
 }

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))

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());
+	}
+
+}