Merge branch 'develop' into f/groupMessages

Conflicts:
	src/main/java/envoy/server/processors/GroupMessageProcessor.java
	src/main/java/envoy/server/processors/MessageProcessor.java

.github/CODEOWNERS

@@ -0,0 +1 @@
+* @CyB3RC0nN0R

README.md

@@ -1,2 +1,3 @@
 # envoy-server-standalone
-Standalone server for the Envoy project
+Standalone server for the 
+<a href="https://github.com/informatik-ag-ngl/envoy-client"><img src="https://raw.githubusercontent.com/informatik-ag-ngl/envoy-client/develop/src/main/resources/icons/envoy_logo.png" align="left" width="200" height="200">Envoy project</a>

src/main/java/enovy/server/util/VersionUtils.java

@@ -0,0 +1,94 @@
+package enovy.server.util;
+
+import java.util.regex.Pattern;
+
+/**
+ * Implements a comparison algorithm between Envoy versions and defines minimal
+ * and maximal client versions compatible with this server.
+ * <p>
+ * Project: <strong>envoy-server-standalone</strong><br>
+ * File: <strong>VersionUtils.java</strong><br>
+ * Created: <strong>23.06.2020</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy Server Standalone v0.1-beta
+ */
+public class VersionUtils {
+
+	/**
+	 * The minimal client version compatible with this server.
+	 * 
+	 * @since Envoy Server Standalone v0.1-beta
+	 */
+	public static final String MIN_CLIENT_VERSION = "0.1-beta";
+
+	/**
+	 * The maximal client version compatible with this server.
+	 * 
+	 * @since Envoy Server Standalone v0.1-beta
+	 */
+	public static final String MAX_CLIENT_VERSION = "0.1-beta";
+
+	private static final Pattern versionPattern = Pattern.compile("(?<major>\\d).(?<minor>\\d)(?:-(?<suffix>\\w+))?");
+
+	private VersionUtils() {}
+
+	/**
+	 * Parses an Envoy Client version string and checks whether that version is
+	 * compatible with this server.
+	 * 
+	 * @param version the version string to parse
+	 * @return {@code true} if the given version is compatible with this server
+	 * @since Envoy Server Standalone v0.1-beta
+	 */
+	public static boolean verifyCompatibility(String version) {
+		final var currentMatcher = versionPattern.matcher(version);
+
+		if (!currentMatcher.matches()) return false;
+
+		final var	minMatcher	= versionPattern.matcher(MIN_CLIENT_VERSION);
+		final var	maxMatcher	= versionPattern.matcher(MAX_CLIENT_VERSION);
+
+		if (!minMatcher.matches() || !maxMatcher.matches()) throw new RuntimeException("Invalid min or max client version configured!");
+
+		// Compare suffixes
+		{
+			final var	currentSuffix	= convertSuffix(currentMatcher.group("suffix"));
+			final var	minSuffix		= convertSuffix(minMatcher.group("suffix"));
+			final var	maxSuffix		= convertSuffix(maxMatcher.group("suffix"));
+
+			if (currentSuffix < minSuffix || currentSuffix > maxSuffix) return false;
+		}
+
+		// Compare major
+		{
+			final var	currentMajor	= Integer.parseInt(currentMatcher.group("major"));
+			final var	minMajor		= Integer.parseInt(minMatcher.group("major"));
+			final var	maxMajor		= Integer.parseInt(maxMatcher.group("major"));
+
+			if (currentMajor < minMajor || currentMajor > maxMajor) return false;
+		}
+
+		// Compare minor
+		{
+			final var	currentMinor	= Integer.parseInt(currentMatcher.group("minor"));
+			final var	minMinor		= Integer.parseInt(minMatcher.group("minor"));
+			final var	maxMinor		= Integer.parseInt(maxMatcher.group("minor"));
+
+			if (currentMinor < minMinor || currentMinor > maxMinor) return false;
+		}
+
+		return true;
+	}
+
+	private static int convertSuffix(String suffix) {
+		switch (suffix == null ? "" : suffix) {
+			case "alpha":
+				return 0;
+			case "beta":
+				return 1;
+			default:
+				return 2;
+		}
+	}
+}

src/main/java/enovy/server/util/package-info.java

@@ -0,0 +1,11 @@
+/**
+ * This package contains utility classes used in Envoy Server.
+ * <p>
+ * Project: <strong>envoy-server-standalone</strong><br>
+ * File: <strong>package-info.java</strong><br>
+ * Created: <strong>23.06.2020</strong><br>
+ * 
+ * @author Kai S. K. Engelbart
+ * @since Envoy Server Standalone v0.1-beta
+ */
+package enovy.server.util;

src/main/java/envoy/server/Startup.java

@@ -46,7 +46,7 @@ public class Startup {
 		final var items = new HashMap<String, ConfigItem<?>>();
 		items.put("homeDirectory",
 				new ConfigItem<>("homeDirectory", "h", File::new, new File(System.getProperty("user.home"), ".envoy-server"), true));
-		items.put("fileLevelBarrier", new ConfigItem<>("fileLevelBarrier", "fb", Level::parse, Level.SEVERE, true));
+		items.put("fileLevelBarrier", new ConfigItem<>("fileLevelBarrier", "fb", Level::parse, Level.WARNING, true));
 		items.put("consoleLevelBarrier", new ConfigItem<>("consoleLevelBarrier", "cb", Level::parse, Level.FINEST, true));
 
 		final var config = new Config();

src/main/java/envoy/server/data/Contact.java

@@ -1,19 +1,9 @@
 package envoy.server.data;
 
-import java.util.Date;
+import java.time.LocalDateTime;
 import java.util.Set;
 
-import javax.persistence.CascadeType;
+import javax.persistence.*;
-import javax.persistence.Entity;
-import javax.persistence.FetchType;
-import javax.persistence.GeneratedValue;
-import javax.persistence.Id;
-import javax.persistence.Inheritance;
-import javax.persistence.InheritanceType;
-import javax.persistence.ManyToMany;
-import javax.persistence.Table;
-import javax.persistence.Temporal;
-import javax.persistence.TemporalType;
 
 /**
  * This class acts as a superclass for all contacts, being {@link User}s and
@@ -29,7 +19,7 @@ import javax.persistence.TemporalType;
 
 @Entity
 @Table(name = "contacts")
-@Inheritance(strategy = InheritanceType.JOINED)
+@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
 public abstract class Contact {
 
 	@Id
@@ -37,10 +27,10 @@ public abstract class Contact {
 	protected long		id;
 	protected String	name;
 
-	@Temporal(TemporalType.TIMESTAMP)
+	@Column(name = "creation_date")
-	private Date creationDate;
+	private LocalDateTime creationDate;
 
-	@ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
+	@ManyToMany(fetch = FetchType.EAGER)
 	protected Set<Contact> contacts;
 
 	/**
@@ -104,17 +94,14 @@ public abstract class Contact {
 	 * @return the creationDate
 	 * @since Envoy Server Standalone v0.1-beta
 	 */
-	public Date getCreationDate() { return creationDate; }
+	public LocalDateTime getCreationDate() { return creationDate; }
 
 	/**
 	 * @param creationDate the creationDate to set
 	 * @since Envoy Server Standalone v0.1-beta
 	 */
-	public void setCreationDate(Date creationDate) { this.creationDate = creationDate; }
+	public void setCreationDate(LocalDateTime creationDate) { this.creationDate = creationDate; }
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
-	public String toString() { return String.format("%s[id=%d,name=%s, contacts=%s]", getClass().getSimpleName(), id, name, contacts); }
+	public String toString() { return String.format("%s[id=%d,name=%s, %d contact(s)]", getClass().getSimpleName(), id, name, contacts.size()); }
 }

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

@@ -5,7 +5,6 @@ import java.util.stream.Collectors;
 import javax.persistence.Entity;
 import javax.persistence.NamedQueries;
 import javax.persistence.NamedQuery;
-import javax.persistence.Table;
 
 /**
  * Represents a group inside the database. Referred to as "server group" as
@@ -19,7 +18,6 @@ import javax.persistence.Table;
  * @since Envoy Server Standalone v0.1-alpha
  */
 @Entity
-@Table(name = "groups")
 @NamedQueries({
 	@NamedQuery(
 		name = Group.findByName,
@@ -46,17 +44,11 @@ public class Group extends Contact {
 	 */
 	public static final String findPendingGroups = "Group.findPendingGroups";
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public envoy.data.Group toCommon() {
 		return new envoy.data.Group(id, name, contacts.parallelStream().map(User.class::cast).map(User::toFlatCommon).collect(Collectors.toSet()));
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	protected envoy.data.Group toFlatCommon() { return toCommon(); }
 }

src/main/java/envoy/server/data/GroupMessage.java

@@ -3,10 +3,7 @@ package envoy.server.data;
 import java.util.Date;
 import java.util.Map;
 
-import javax.persistence.ElementCollection;
+import javax.persistence.*;
-import javax.persistence.Entity;
-import javax.persistence.Temporal;
-import javax.persistence.TemporalType;
 
 import envoy.data.MessageBuilder;
 
@@ -24,6 +21,7 @@ public class GroupMessage extends Message {
 	@ElementCollection
 	private Map<Long, envoy.data.Message.MessageStatus> memberMessageStatus;
 
+	@Column(name = "last_status_change_date")
 	@Temporal(TemporalType.TIMESTAMP)
 	protected Date lastStatusChangeDate;
 
@@ -64,7 +62,6 @@ public class GroupMessage extends Message {
 			.setForwarded(forwarded)
 			.setStatus(status)
 			.setText(text)
-			// .setAttachment(attachment) TODO make this work
 			.buildGroupMessage((envoy.data.Group) recipient.toCommon(), memberMessageStatus);
 		groupMessage.setReceivedDate(receivedDate);
 		groupMessage.setReadDate(readDate);

src/main/java/envoy/server/data/Message.java

@@ -1,9 +1,12 @@
 package envoy.server.data;
 
-import java.util.Date;
+import static envoy.data.Message.MessageStatus.*;
+
+import java.time.LocalDateTime;
 
 import javax.persistence.*;
 
+import envoy.data.Message.MessageStatus;
 import envoy.data.MessageBuilder;
 
 /**
@@ -49,14 +52,14 @@ public class Message {
 	@JoinColumn
 	protected Contact recipient;
 
-	@Temporal(TemporalType.TIMESTAMP)
+	@Column(name = "creation_date")
-	protected Date creationDate;
+	protected LocalDateTime creationDate;
 
-	@Temporal(TemporalType.TIMESTAMP)
+	@Column(name = "received_date")
-	protected Date receivedDate;
+	protected LocalDateTime receivedDate;
 
-	@Temporal(TemporalType.TIMESTAMP)
+	@Column(name = "read_date")
-	protected Date readDate;
+	protected LocalDateTime readDate;
 
 	protected String							text;
 	protected envoy.data.Message.MessageStatus	status;
@@ -88,7 +91,7 @@ public class Message {
 		sender			= persistenceManager.getUserByID(message.getSenderID());
 		recipient		= persistenceManager.getContactByID(message.getRecipientID());
 		forwarded		= message.isForwarded();
-		// TODO: attachment = message.getAttachment().toByteArray();DOES NOT WORK YET
+		// TODO: Attachment
 	}
 
 	/**
@@ -104,13 +107,34 @@ public class Message {
 			.setDate(creationDate)
 			.setStatus(status)
 			.setForwarded(forwarded)
-			// .setAttachment(attachment) TODO make this work
 			.build();
 		message.setReceivedDate(receivedDate);
 		message.setReadDate(readDate);
 		return message;
 	}
 
+	/**
+	 * Sets the message status to {@link MessageStatus#RECEIVED} and sets the
+	 * current time stamp as the received date.
+	 * 
+	 * @since Envoy Server Standalone v0.1-beta
+	 */
+	public void received() {
+		receivedDate	= LocalDateTime.now();
+		status			= RECEIVED;
+	}
+
+	/**
+	 * Sets the message status to {@link MessageStatus#READ} and sets the
+	 * current time stamp as the read date.
+	 * 
+	 * @since Envoy Server Standalone v0.1-beta
+	 */
+	public void read() {
+		readDate	= LocalDateTime.now();
+		status		= READ;
+	}
+
 	/**
 	 * @return the id of a {link envoy.data.Message}
 	 * @since Envoy Server Standalone v0.1-alpha
@@ -154,41 +178,41 @@ public class Message {
 	 * @return the date at which a {link envoy.data.Message} has been created
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public Date getCreationDate() { return creationDate; }
+	public LocalDateTime getCreationDate() { return creationDate; }
 
 	/**
 	 * @param creationDate the creation date to set
 	 * @since Envoy Server Standalone v0.1-alpha
 	 * @see Message#getCreationDate()
 	 */
-	public void setCreationDate(Date creationDate) { this.creationDate = creationDate; }
+	public void setCreationDate(LocalDateTime creationDate) { this.creationDate = creationDate; }
 
 	/**
 	 * @return the date at which a {link envoy.data.Message} has been received by
 	 *         the server
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public Date getReceivedDate() { return receivedDate; }
+	public LocalDateTime getReceivedDate() { return receivedDate; }
 
 	/**
 	 * @param receivedDate the received date to set
 	 * @since Envoy Server Standalone v0.1-alpha
 	 * @see Message#getReceivedDate()
 	 */
-	public void setReceivedDate(Date receivedDate) { this.receivedDate = receivedDate; }
+	public void setReceivedDate(LocalDateTime receivedDate) { this.receivedDate = receivedDate; }
 
 	/**
 	 * @return the date at which a {link envoy.data.Message} has been read
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public Date getReadDate() { return readDate; }
+	public LocalDateTime getReadDate() { return readDate; }
 
 	/**
 	 * @param readDate the read date to set
 	 * @since Envoy Server Standalone v0.1-alpha
 	 * @see Message#getReadDate()
 	 */
-	public void setReadDate(Date readDate) { this.readDate = readDate; }
+	public void setReadDate(LocalDateTime readDate) { this.readDate = readDate; }
 
 	/**
 	 * @return the status of a {link envoy.data.Message}

src/main/java/envoy/server/data/PersistenceManager.java

@@ -1,6 +1,6 @@
 package envoy.server.data;
 
-import java.util.Date;
+import java.time.LocalDateTime;
 import java.util.List;
 
 import javax.persistence.EntityManager;
@@ -38,7 +38,7 @@ public class PersistenceManager {
 				.getOnlineUsers()
 				.stream()
 				.map(this::getUserByID)
-				.forEach(user -> { user.setStatus(UserStatus.OFFLINE); user.setLastSeen(new Date()); entityManager.merge(user); });
+				.forEach(user -> { user.setStatus(UserStatus.OFFLINE); user.setLastSeen(LocalDateTime.now()); entityManager.merge(user); });
 			transaction.commit();
 		}));
 	}
@@ -117,7 +117,7 @@ public class PersistenceManager {
 	 * Searches for a {@link User} with a specific ID.
 	 *
 	 * @param id the id to search for
-	 * @return the user with the specified id
+	 * @return the user with the specified ID or {@code null} if none was found
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	public User getUserByID(long id) { return entityManager.find(User.class, id); }
@@ -126,7 +126,7 @@ public class PersistenceManager {
 	 * Searches for a {@link Group} with a specific ID.
 	 *
 	 * @param id the id to search for
-	 * @return the group with the specific id
+	 * @return the group with the specified ID or {@code null} if none was found
 	 * @since Envoy Server Standalone v0.1-beta
 	 */
 	public Group getGroupByID(long id) { return entityManager.find(Group.class, id); }
@@ -135,7 +135,7 @@ public class PersistenceManager {
 	 * Searches for a {@link Contact} with a specific ID.
 	 *
 	 * @param id the id to search for
-	 * @return the contact with the specific id
+	 * @return the contact with the specified ID or {@code null} if none was found
 	 * @since Envoy Server Standalone v0.1-beta
 	 */
 	public Contact getContactByID(long id) { return entityManager.find(Contact.class, id); }
@@ -166,7 +166,7 @@ public class PersistenceManager {
 	 * Searches for a {@link Message} with a specific id.
 	 *
 	 * @param id the id to search for
-	 * @return the message with the specified id
+	 * @return the message with the specified ID or {@code null} if none is found
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	public Message getMessageByID(long id) { return entityManager.find(Message.class, id); }
@@ -213,26 +213,26 @@ public class PersistenceManager {
 	}
 
 	/**
-	 * Adds a user to the contact list of another user and vice versa.
+	 * Adds a contact to the contact list of another contact and vice versa.
 	 *
-	 * @param userId1 the ID of the first user
+	 * @param contactID1 the ID of the first contact
-	 * @param userId2 the ID of the second user
+	 * @param contactID2 the ID of the second contact
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public void addUserContact(long userId1, long userId2) {
+	public void addContactBidirectional(long contactID1, long contactID2) {
 
 		// Get users by ID
-		Contact	u1	= getContactByID(userId1);
+		Contact	c1	= getContactByID(contactID1);
-		Contact	u2	= getContactByID(userId2);
+		Contact	c2	= getContactByID(contactID2);
 
 		// Add users to each others contact lists
-		u1.getContacts().add(u2);
+		c1.getContacts().add(c2);
-		u2.getContacts().add(u1);
+		c2.getContacts().add(c1);
 
 		// Synchronize changes with the database
 		transaction.begin();
-		entityManager.merge(u1);
+		entityManager.merge(c1);
-		entityManager.merge(u2);
+		entityManager.merge(c2);
 		transaction.commit();
 	}
 

src/main/java/envoy/server/data/User.java

@@ -1,6 +1,6 @@
 package envoy.server.data;
 
-import java.util.Date;
+import java.time.LocalDateTime;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -22,7 +22,6 @@ import envoy.data.User.UserStatus;
  * @since Envoy Server Standalone v0.1-alpha
  */
 @Entity
-@Table(name = "users")
 @NamedQueries({
 	@NamedQuery(
 		name = User.findByName,
@@ -63,24 +62,19 @@ public class User extends Contact {
 	 */
 	public static final String searchByName = "User.searchByName";
 
+	@Column(name = "password_hash")
 	private byte[] passwordHash;
 
-	@Temporal(TemporalType.TIMESTAMP)
+	@Column(name = "last_seen")
-	private Date lastSeen;
+	private LocalDateTime lastSeen;
 
 	private UserStatus status;
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public envoy.data.User toCommon() {
 		return new envoy.data.User(id, name, status, contacts.parallelStream().map(Contact::toFlatCommon).collect(Collectors.toSet()));
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	protected envoy.data.User toFlatCommon() { return new envoy.data.User(id, name, status, Set.of()); }
 
@@ -100,13 +94,13 @@ public class User extends Contact {
 	 * @return the last date the user has been online
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public Date getLastSeen() { return lastSeen; }
+	public LocalDateTime getLastSeen() { return lastSeen; }
 
 	/**
 	 * @param lastSeen the latest date at which the user has been online to set
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public void setLastSeen(Date lastSeen) { this.lastSeen = lastSeen; }
+	public void setLastSeen(LocalDateTime lastSeen) { this.lastSeen = lastSeen; }
 
 	/**
 	 * @return the status

src/main/java/envoy/server/net/ConnectionManager.java

@@ -1,10 +1,7 @@
 package envoy.server.net;
 
-import java.util.Date;
+import java.time.LocalDateTime;
-import java.util.HashMap;
+import java.util.*;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
 import java.util.stream.Collectors;
 
 import com.jenkov.nioserver.ISocketIdListener;
@@ -53,9 +50,9 @@ public class ConnectionManager implements ISocketIdListener {
 	public void socketCancelled(long socketID) {
 		if (!pendingSockets.remove(socketID)) {
 			// Notify contacts of this users offline-going
-			envoy.server.data.User user = PersistenceManager.getInstance().getUserByID(getUserIdBySocketId(socketID));
+			envoy.server.data.User user = PersistenceManager.getInstance().getUserByID(getUserIdBySocketID(socketID));
 			user.setStatus(UserStatus.OFFLINE);
-			user.setLastSeen(new Date());
+			user.setLastSeen(LocalDateTime.now());
 			UserStatusChangeProcessor.updateUserStatus(user);
 
 			// Remove the socket
@@ -83,14 +80,14 @@ public class ConnectionManager implements ISocketIdListener {
 	 * @return the ID of the socket
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public long getSocketId(long userID) { return sockets.get(userID); }
+	public long getSocketID(long userID) { return sockets.get(userID); }
 
 	/**
 	 * @param socketID the id of the socket whose User is needed
 	 * @return the userId associated with this socketId
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public long getUserIdBySocketId(long socketID) {
+	public long getUserIdBySocketID(long socketID) {
 		return sockets.entrySet().stream().filter(entry -> entry.getValue().equals(socketID)).findFirst().get().getKey();
 	}
 
@@ -108,8 +105,6 @@ public class ConnectionManager implements ISocketIdListener {
 	public Set<Long> getOnlineUsers() { return sockets.keySet(); }
 
 	/**
-	 * Returns all members of a group who are currently online.
-	 *
 	 * @param group the group to search for
 	 * @return a set of all IDs of currently active members in this group
 	 * @since Envoy Server Standalone v0.1-beta

src/main/java/envoy/server/net/ObjectWriteProxy.java

@@ -43,7 +43,6 @@ public class ObjectWriteProxy {
 		// Create message targeted at the client
 		final Message response = writeProxy.getMessage();
 		response.socketId = recipientSocketID;
-
 		logger.fine("Sending " + obj);
 
 		// Serialize object to byte array

src/main/java/envoy/server/processors/ContactOperationProcessor.java

@@ -4,7 +4,7 @@ import java.io.IOException;
 import java.util.logging.Logger;
 
 import envoy.event.ElementOperation;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
@@ -18,25 +18,25 @@ import envoy.util.EnvoyLog;
  * @author Kai S. K. Engelbart
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class ContactOperationProcessor implements ObjectProcessor<ContactOperationEvent> {
+public class ContactOperationProcessor implements ObjectProcessor<ContactOperation> {
 
 	private static final ConnectionManager connectionManager = ConnectionManager.getInstance();
 	private static final Logger				logger				= EnvoyLog.getLogger(ContactOperationProcessor.class);
 
 	@Override
-	public void process(ContactOperationEvent evt, long socketId, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(ContactOperation evt, long socketId, ObjectWriteProxy writeProxy) throws IOException {
 		switch (evt.getOperationType()) {
 			case ADD:
-				final long userID = ConnectionManager.getInstance().getUserIdBySocketId(socketId);
+				final long userID = ConnectionManager.getInstance().getUserIdBySocketID(socketId);
 				final long contactId = evt.get().getID();
 
 				logger.fine(String.format("Adding user %s to the contact list of user %d.%n", evt.get(), userID));
-				PersistenceManager.getInstance().addUserContact(userID, contactId);
+				PersistenceManager.getInstance().addContactBidirectional(userID, contactId);
 
 				// Notify the contact if online
 				if (ConnectionManager.getInstance().isOnline(contactId))
-					writeProxy.write(connectionManager.getSocketId(contactId),
+					writeProxy.write(connectionManager.getSocketID(contactId),
-							new ContactOperationEvent(PersistenceManager.getInstance().getUserByID(userID).toCommon(), ElementOperation.ADD));
+							new ContactOperation(PersistenceManager.getInstance().getUserByID(userID).toCommon(), ElementOperation.ADD));
 				break;
 			default:
 				logger.warning(String.format("Received %s with an unsupported operation.%n", evt));
@@ -44,5 +44,5 @@ public class ContactOperationProcessor implements ObjectProcessor<ContactOperati
 	}
 
 	@Override
-	public Class<ContactOperationEvent> getInputClass() { return ContactOperationEvent.class; }
+	public Class<ContactOperation> getInputClass() { return ContactOperation.class; }
 }

src/main/java/envoy/server/processors/ContactSearchProcessor.java

@@ -33,7 +33,7 @@ public class ContactSearchProcessor implements ObjectProcessor<ContactSearchRequ
 	public void process(ContactSearchRequest request, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		writeProxy.write(socketID,
 				new ContactSearchResult(PersistenceManager.getInstance()
-					.searchUsers(request.get(), ConnectionManager.getInstance().getUserIdBySocketId(socketID))
+					.searchUsers(request.get(), ConnectionManager.getInstance().getUserIdBySocketID(socketID))
 					.stream()
 					.map(User::toCommon)
 					.collect(Collectors.toList())));

src/main/java/envoy/server/processors/GroupCreationProcessor.java

@@ -4,8 +4,8 @@ import java.io.IOException;
 import java.util.HashSet;
 
 import envoy.event.ElementOperation;
-import envoy.event.GroupCreationEvent;
+import envoy.event.GroupCreation;
-import envoy.event.contact.ContactOperationEvent;
+import envoy.event.contact.ContactOperation;
 import envoy.server.data.Contact;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
@@ -19,29 +19,29 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupCreationProcessor implements ObjectProcessor<GroupCreationEvent> {
+public class GroupCreationProcessor implements ObjectProcessor<GroupCreation> {
 
 	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
 
 	@Override
-	public void process(GroupCreationEvent input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(GroupCreation groupCreation, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		envoy.server.data.Group group = new envoy.server.data.Group();
-		group.setName(input.get());
+		group.setName(groupCreation.get());
 		group.setContacts(new HashSet<>());
-		input.getInitialMemberIDs().stream().map(persistenceManager::getUserByID).forEach(group.getContacts()::add);
+		groupCreation.getInitialMemberIDs().stream().map(persistenceManager::getUserByID).forEach(group.getContacts()::add);
-		group.getContacts().add(persistenceManager.getContactByID(connectionManager.getUserIdBySocketId(socketID)));
+		group.getContacts().add(persistenceManager.getContactByID(connectionManager.getUserIdBySocketID(socketID)));
 		group.getContacts().forEach(c -> c.getContacts().add(group));
-		group.getContacts().add(persistenceManager.getUserByID(connectionManager.getUserIdBySocketId(socketID)));
+		group.getContacts().add(persistenceManager.getUserByID(connectionManager.getUserIdBySocketID(socketID)));
 		persistenceManager.addContact(group);
 		group.getContacts()
 			.stream()
 			.map(Contact::getID)
 			.filter(connectionManager::isOnline)
-			.map(connectionManager::getSocketId)
+			.map(connectionManager::getSocketID)
 			.forEach(memberSocketID -> {
 				try {
-					writeProxy.write(memberSocketID, new ContactOperationEvent(group.toCommon(), ElementOperation.ADD));
+						writeProxy.write(memberSocketID, new ContactOperation(group.toCommon(), ElementOperation.ADD));
 				} catch (IOException e) {
 					e.printStackTrace();
 				}
@@ -49,5 +49,5 @@ public class GroupCreationProcessor implements ObjectProcessor<GroupCreationEven
 	}
 
 	@Override
-	public Class<GroupCreationEvent> getInputClass() { return GroupCreationEvent.class; }
+	public Class<GroupCreation> getInputClass() { return GroupCreation.class; }
 }

src/main/java/envoy/server/processors/GroupMessageProcessor.java

@@ -8,7 +8,7 @@ import javax.persistence.EntityExistsException;
 
 import envoy.data.GroupMessage;
 import envoy.data.Message.MessageStatus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
@@ -39,14 +39,14 @@ public class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
 			.replace(members.stream().filter(sender -> groupMessage.getSenderID() == sender.getID()).findAny().get().getID(), MessageStatus.READ);
 
 		// Checks if all memberMessageStatuses are RECEIVED and if so sets the
-		// groupMessage Status to RECEIVED and sends a MessageStatusChangeEvent to the
+		// groupMessage Status to RECEIVED and sends a MessageStatusChange to the
 		// sender, if he is still online.
 		if (!groupMessage.getMemberStatuses().containsValue(MessageStatus.SENT)) {
 			groupMessage.setStatus(MessageStatus.RECEIVED);
-			if (connectionManager.isOnline(connectionManager.getUserIdBySocketId(socketID))) try {
+			if (connectionManager.isOnline(connectionManager.getUserIdBySocketID(socketID))) try {
-				writeProxy.write(socketID, new MessageStatusChangeEvent(groupMessage));
+				writeProxy.write(socketID, new MessageStatusChange(groupMessage));
 			} catch (IOException e) {
-				logger.warning("Sender of the groupMessage online. Failed to send MessageStatusChangeEvent");
+				logger.warning("Sender of the groupMessage online. Failed to send MessageStatusChange");
 				e.printStackTrace();
 			}
 		}
@@ -65,7 +65,7 @@ public class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
 	private void sendToMember(ConnectionManager connectionManager, GroupMessage groupMessage, long memberID, ObjectWriteProxy writeProxy) {
 		if (connectionManager.isOnline(memberID)) try {
 			// If recipient is online, send the groupMessage directly
-			writeProxy.write(connectionManager.getSocketId(memberID), groupMessage);
+			writeProxy.write(connectionManager.getSocketID(memberID), groupMessage);
 		} catch (IOException e) {
 			logger.warning("Recipient online. Failed to send message" + groupMessage.getID());
 			e.printStackTrace();

src/main/java/envoy/server/processors/GroupResizeProcessor.java

@@ -2,7 +2,7 @@ package envoy.server.processors;
 
 import java.io.IOException;
 
-import envoy.event.GroupResizeEvent;
+import envoy.event.GroupResize;
 import envoy.server.data.Contact;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
@@ -16,24 +16,24 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-beta
  */
-public class GroupResizeProcessor implements ObjectProcessor<GroupResizeEvent> {
+public class GroupResizeProcessor implements ObjectProcessor<GroupResize> {
 
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 
 	@Override
-	public void process(GroupResizeEvent input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(GroupResize groupResize, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 
 		// Acquire the group to resize from the database
-		var group = persistenceManager.getGroupByID(input.getGroupID());
+		var group = persistenceManager.getGroupByID(groupResize.getGroupID());
 
 		// Perform the desired operation
-		switch (input.getOperation()) {
+		switch (groupResize.getOperation()) {
 			case ADD:
-				group.getContacts().add(persistenceManager.getUserByID(input.get().getID()));
+				group.getContacts().add(persistenceManager.getUserByID(groupResize.get().getID()));
 				break;
 			case REMOVE:
-				group.getContacts().remove(persistenceManager.getUserByID(input.get().getID()));
+				group.getContacts().remove(persistenceManager.getUserByID(groupResize.get().getID()));
 				break;
 		}
 
@@ -46,7 +46,7 @@ public class GroupResizeProcessor implements ObjectProcessor<GroupResizeEvent> {
 			.stream()
 			.map(Contact::getID)
 			.filter(connectionManager::isOnline)
-			.map(connectionManager::getSocketId)
+			.map(connectionManager::getSocketID)
 			.forEach(memberSocketID -> {
 				try {
 					writeProxy.write(memberSocketID, commonGroup);
@@ -57,5 +57,5 @@ public class GroupResizeProcessor implements ObjectProcessor<GroupResizeEvent> {
 	}
 
 	@Override
-	public Class<GroupResizeEvent> getInputClass() { return GroupResizeEvent.class; }
+	public Class<GroupResize> getInputClass() { return GroupResize.class; }
 }

src/main/java/envoy/server/processors/IDGeneratorRequestProcessor.java

@@ -1,14 +1,12 @@
 package envoy.server.processors;
 
 import java.io.IOException;
-import java.util.logging.Logger;
 
 import envoy.data.IDGenerator;
 import envoy.event.IDGeneratorRequest;
 import envoy.server.data.ConfigItem;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ObjectWriteProxy;
-import envoy.util.EnvoyLog;
 
 /**
  * Project: <strong>envoy-server-standalone</strong><br>
@@ -22,17 +20,13 @@ import envoy.util.EnvoyLog;
 public class IDGeneratorRequestProcessor implements ObjectProcessor<IDGeneratorRequest> {
 
 	private static final long ID_RANGE = 200;
-	private static final Logger	logger		= EnvoyLog.getLogger(IDGeneratorRequestProcessor.class);
 
 	@Override
 	public Class<IDGeneratorRequest> getInputClass() { return IDGeneratorRequest.class; }
 
 	@Override
 	public void process(IDGeneratorRequest input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
-		logger.fine("Received id generation request.");
+		writeProxy.write(socketID, createIDGenerator());
-		var generator = createIDGenerator();
-		logger.info("Sending new id generator " + generator);
-		writeProxy.write(socketID, generator);
 	}
 
 	/**

src/main/java/envoy/server/processors/LoginCredentialProcessor.java

@@ -1,21 +1,26 @@
 package envoy.server.processors;
 
+import static envoy.data.User.UserStatus.ONLINE;
+import static envoy.event.HandshakeRejection.*;
+
 import java.io.IOException;
-import java.util.*;
+import java.time.LocalDateTime;
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.logging.Logger;
 
 import javax.persistence.NoResultException;
 
+import enovy.server.util.VersionUtils;
 import envoy.data.LoginCredentials;
 import envoy.data.Message.MessageStatus;
-import envoy.data.User;
+import envoy.event.HandshakeRejection;
-import envoy.data.User.UserStatus;
+import envoy.event.MessageStatusChange;
-import envoy.event.HandshakeRejectionEvent;
-import envoy.event.MessageStatusChangeEvent;
-import envoy.server.data.Message;
 import envoy.server.data.PersistenceManager;
+import envoy.server.data.User;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
+import envoy.util.Bounds;
 import envoy.util.EnvoyLog;
 
 /**
@@ -29,7 +34,7 @@ import envoy.util.EnvoyLog;
  * @author Maximilian Käfer
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class LoginCredentialProcessor implements ObjectProcessor<LoginCredentials> {
+public final class LoginCredentialProcessor implements ObjectProcessor<LoginCredentials> {
 
 	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
@@ -37,118 +42,99 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 	private static final Logger logger = EnvoyLog.getLogger(LoginCredentialProcessor.class);
 
 	@Override
-	public void process(LoginCredentials input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+
+		// Cache this write proxy for user-independant notifications
 		UserStatusChangeProcessor.setWriteProxy(writeProxy);
-		logger.info(String.format("Received login credentials %s from socket ID %d", input, socketID));
 
-		envoy.server.data.User user = getUser(input, socketID, writeProxy);
+		if (!VersionUtils.verifyCompatibility(credentials.getClientVersion())) {
-
+			logger.info("The client has the wrong version.");
-		// Not logged in successfully
+			writeProxy.write(socketID, new HandshakeRejection(WRONG_VERSION));
-		if (user == null) {
-			logger.info("Rejecting handshake on socket " + socketID);
 			return;
 		}
+
+		// Acquire a user object (or reject the handshake if that's impossible)
+		User user = null;
+		if (!credentials.isRegistration()) {
+			try {
+				user = persistenceManager.getUserByName(credentials.getIdentifier());
+
+				// Checking if user is already online
+				if (connectionManager.isOnline(user.getID())) {
+					logger.warning(user + " is already online!");
+					writeProxy.write(socketID, new HandshakeRejection(INTERNAL_ERROR));
+					return;
+				}
+				// Evaluating the correctness of the password hash
+				if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) {
+					logger.info(user + " has entered the wrong password.");
+					writeProxy.write(socketID, new HandshakeRejection(WRONG_PASSWORD_OR_USER));
+					return;
+				}
+			} catch (NoResultException e) {
+				logger.info("The requested user does not exist.");
+				writeProxy.write(socketID, new HandshakeRejection(WRONG_PASSWORD_OR_USER));
+				return;
+			}
+		} else {
+			// Validate user name
+			if (!Bounds.isValidContactName(credentials.getIdentifier())) {
+				logger.info("The requested user name is not valid.");
+				writeProxy.write(socketID, new HandshakeRejection(INTERNAL_ERROR));
+				return;
+			}
+				try {
+					// Checking that no user already has this identifier
+					PersistenceManager.getInstance().getUserByName(credentials.getIdentifier());
+
+					// This code only gets executed if this user already exists
+					logger.info("The requested user already exists.");
+					writeProxy.write(socketID, new HandshakeRejection(USERNAME_TAKEN));
+					return;
+				} catch (NoResultException e) {
+					// Creation of a new user
+					user = new User();
+					user.setName(credentials.getIdentifier());
+					user.setLastSeen(LocalDateTime.now());
+					user.setStatus(ONLINE);
+					user.setPasswordHash(credentials.getPasswordHash());
+					user.setContacts(new HashSet<>());
+					persistenceManager.addContact(user);
+					logger.info("Registered new " + user);
+				}
+		}
+
+		logger.info(user + " successfully authenticated.");
 		connectionManager.registerUser(user.getID(), socketID);
 
-		// Notifies contacts of this users online-going and updates his status in the
+		// Change status and notify contacts about it
-		// database
+		user.setStatus(ONLINE);
-		user.setStatus(UserStatus.ONLINE);
 		UserStatusChangeProcessor.updateUserStatus(user);
 
-		// Complete handshake
+		// Complete the handshake
-		logger.fine("Sending user...");
 		writeProxy.write(socketID, user.toCommon());
-		logger.fine("Acquiring pending messages for the client...");
+
-		List<Message> pendingMessages = PersistenceManager.getInstance().getPendingMessages(user);
+		final var pendingMessages = PersistenceManager.getInstance().getPendingMessages(user);
-		for (Message msg : pendingMessages)
+		logger.fine("Sending " + pendingMessages.size() + " pending messages to " + user + "...");
+
+		for (var msg : pendingMessages) {
+			final var msgCommon = msg.toCommon();
 			if (msg.getStatus() == MessageStatus.SENT) {
-				logger.info("Sending message " + msg.toCommon());
+
-				writeProxy.write(socketID, msg.toCommon());
+				// Send the message
-				msg.setReceivedDate(new Date());
+				writeProxy.write(socketID, msgCommon);
-				msg.setStatus(MessageStatus.RECEIVED);
+				msg.received();
-				if (connectionManager.isOnline(msg.getSender().getID())) {
-					var evt = new MessageStatusChangeEvent(msg.toCommon());
-					logger.info("Sending messageStatusChangeEvent to sender " + evt);
-					writeProxy.write(connectionManager.getSocketId(msg.getSender().getID()), evt);
-				}
 				PersistenceManager.getInstance().updateMessage(msg);
-			} else {
+
-				var evt = new MessageStatusChangeEvent(msg.toCommon());
+				// Notify the sender about the delivery
-				logger.info("Sending messageStatusChangeEvent " + evt);
+				if (connectionManager.isOnline(msg.getSender().getID())) {
-				writeProxy.write(socketID, evt);
+					msgCommon.nextStatus();
+					writeProxy.write(connectionManager.getSocketID(msg.getSender().getID()), new MessageStatusChange(msgCommon));
+				}
+			} else writeProxy.write(socketID, new MessageStatusChange(msgCommon));
 		}
 	}
 
 	@Override
 	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
-
-	private envoy.server.data.User getUser(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) throws IOException {
-		return credentials.isRegistration() ? newUser(credentials, socketID, writeProxy) : checkForExistingUser(credentials, socketID, writeProxy);
-	}
-
-	/**
-	 * @param credentials the input to evaluate
-	 * @param socketID    the socket ID at which the client performing the handshake
-	 *                    is connected
-	 * @param writeProxy  the {@link ObjectWriteProxy} to use if login was not
-	 *                    successful
-	 * @return the database user matching the login credentials
-	 * @throws IOException if sending the failed login back to the client failed
-	 * @since Envoy Server Standalone v0.1-alpha
-	 */
-	private envoy.server.data.User checkForExistingUser(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) throws IOException {
-		try {
-			envoy.server.data.User user = persistenceManager.getUserByName(credentials.getIdentifier());
-
-			// Checking if user is already online
-			if (connectionManager.isOnline(user.getID())) {
-				writeProxy.write(socketID, new HandshakeRejectionEvent(HandshakeRejectionEvent.INTERNAL_ERROR));
-				return null;
-			}
-			// Evaluating the correctness of the password hash
-			if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) {
-				writeProxy.write(socketID, new HandshakeRejectionEvent(HandshakeRejectionEvent.WRONG_PASSWORD_OR_USER));
-				return null;
-			}
-			return user;
-		} catch (NoResultException e) {
-			// Checking if user exists
-			writeProxy.write(socketID, new HandshakeRejectionEvent(HandshakeRejectionEvent.INTERNAL_ERROR));
-		} catch (InputMismatchException e) {
-			// Checking if the given password hash is correct
-			writeProxy.write(socketID, new HandshakeRejectionEvent(HandshakeRejectionEvent.WRONG_PASSWORD_OR_USER));
-		}
-		return null;
-	}
-
-	/**
-	 * @param credentials the credentials upon which to create the new {@link User}
-	 * @param socketID    the socketID at which the client performing the handshake
-	 *                    is connected
-	 * @param writeProxy  the write proxy used to notify the client about handshake
-	 *                    rejection
-	 * @return the newly created {@link User}
-	 * @throws IOException if sending the failed login back to the client failed
-	 * @since Envoy Server Standalone v0.1-alpha
-	 */
-	private envoy.server.data.User newUser(LoginCredentials credentials, long socketID, ObjectWriteProxy writeProxy) throws IOException {
-		try {
-			// Checking that no user already has this identifier
-			PersistenceManager.getInstance().getUserByName(credentials.getIdentifier());
-			// this code only gets executed if this user already exists
-			writeProxy.write(socketID, new HandshakeRejectionEvent(HandshakeRejectionEvent.INTERNAL_ERROR));
-			return null;
-		} catch (NoResultException e) {
-			// Creation of a new user
-			envoy.server.data.User user;
-			user = new envoy.server.data.User();
-			user.setName(credentials.getIdentifier());
-			user.setLastSeen(new Date());
-			user.setStatus(User.UserStatus.ONLINE);
-			user.setPasswordHash(credentials.getPasswordHash());
-			user.setContacts(new HashSet<>());
-			persistenceManager.addContact(user);
-			return user;
-		}
-	}
 }

src/main/java/envoy/server/processors/MessageProcessor.java

@@ -1,22 +1,21 @@
 package envoy.server.processors;
 
 import java.io.IOException;
-import java.util.Date;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import javax.persistence.EntityExistsException;
 
 import envoy.data.Message;
-import envoy.data.Message.MessageStatus;
+import envoy.event.MessageStatusChange;
-import envoy.event.MessageStatusChangeEvent;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 import envoy.util.EnvoyLog;
 
 /**
- * This {@link ObjectProcessor} handles incoming {@link Message}s.<br>
+ * This {@link ObjectProcessor} handles incoming {@link Message}s.
- * <br>
+ * <p>
  * Project: <strong>envoy-server-standalone</strong><br>
  * File: <strong>MessageProcessor.java</strong><br>
  * Created: <strong>30.12.2019</strong><br>
@@ -27,6 +26,8 @@ import envoy.util.EnvoyLog;
  */
 public class MessageProcessor implements ObjectProcessor<Message> {
 
+	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
+	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 	private static final Logger				logger				= EnvoyLog.getLogger(MessageProcessor.class);
 
 	@Override
@@ -36,35 +37,32 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 		if (message.getClass().equals(envoy.data.GroupMessage.class)) return;
 
 		message.nextStatus();
-		ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 
-		sendToUser(connectionManager, message, writeProxy);
+		// Convert to server message
-		if (message.getStatus() != MessageStatus.SENT) {
+		final var serverMessage = new envoy.server.data.Message(message);
-			// Sending a messageStatusChangeEvent to the sender
-			try {
-				writeProxy.write(socketID, new MessageStatusChangeEvent(message));
-			} catch (IOException e) {
-				logger.warning("Could not send messageStatusChangeEvent to the sender of this message with ID: " + message.getID());
-				e.printStackTrace();
-			}
-		}
-		try {
-			PersistenceManager.getInstance().addMessage(new envoy.server.data.Message(message));
-		} catch (EntityExistsException e) {
-			logger.warning("Received a message with an id that already exists");
-		}
-	}
 
-	private void sendToUser(ConnectionManager connectionManager, Message message, ObjectWriteProxy writeProxy) {
+		try {
-		if (connectionManager.isOnline(message.getRecipientID())) try {
+
-			// If recipient is online, send the message directly
+			// Persist the message
-			writeProxy.write(connectionManager.getSocketId(message.getRecipientID()), message);
+			persistenceManager.addMessage(serverMessage);
-			// Update the message status to RECEIVED
+
-			message.setReceivedDate(new Date());
+			// Send the message to the recipient if online
+			if (connectionManager.isOnline(message.getRecipientID())) {
+				writeProxy.write(connectionManager.getSocketID(message.getRecipientID()), message);
+
+				// Increment status
 				message.nextStatus();
+				serverMessage.received();
+				persistenceManager.updateMessage(serverMessage);
+
+				// Notify the sender about the delivery
+				// Note that the exact time stamp might differ slightly
+				writeProxy.write(socketID, new MessageStatusChange(message));
+			}
+		} catch (EntityExistsException e) {
+			logger.log(Level.WARNING, "Received " + message + " with an ID that already exists!");
 		} catch (IOException e) {
-			logger.warning("Recipient online. Failed to send message" + message.getID());
+			logger.log(Level.WARNING, "Failed to deliver " + message + ":", e);
-			e.printStackTrace();
 		}
 	}
 

src/main/java/envoy/server/processors/MessageStatusChangeProcessor.java

@@ -3,7 +3,7 @@ package envoy.server.processors;
 import java.io.IOException;
 
 import envoy.data.Message.MessageStatus;
-import envoy.event.MessageStatusChangeEvent;
+import envoy.event.MessageStatusChange;
 import envoy.exception.EnvoyException;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
@@ -17,26 +17,25 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class MessageStatusChangeProcessor implements ObjectProcessor<MessageStatusChangeEvent> {
+public class MessageStatusChangeProcessor implements ObjectProcessor<MessageStatusChange> {
 
 	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
 
 	@Override
-	public void process(MessageStatusChangeEvent input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(MessageStatusChange statusChange, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		// Any other status than READ is not supposed to be sent to the server
-		if (input.get() != MessageStatus.READ) throw new IOException(new EnvoyException("Message " + input + " has an invalid status"));
+		if (statusChange.get() != MessageStatus.READ) throw new IOException(new EnvoyException(statusChange + " has an invalid status"));
 
-		envoy.server.data.Message msg = persistenceManager.getMessageByID(input.getID());
+		final var msg = persistenceManager.getMessageByID(statusChange.getID());
-		msg.setStatus(input.get());
+		msg.read();
-		msg.setReadDate(input.getDate());
 		persistenceManager.updateMessage(msg);
 
 		// Notifies the sender of the message about the status-update to READ
-		final long senderId = msg.getSender().getID();
+		final long senderID = msg.getSender().getID();
-		if (connectionManager.isOnline(senderId)) writeProxy.write(connectionManager.getSocketId(senderId), input);
+		if (connectionManager.isOnline(senderID)) writeProxy.write(connectionManager.getSocketID(senderID), statusChange);
 	}
 
 	@Override
-	public Class<MessageStatusChangeEvent> getInputClass() { return MessageStatusChangeEvent.class; }
+	public Class<MessageStatusChange> getInputClass() { return MessageStatusChange.class; }
 }

src/main/java/envoy/server/processors/NameChangeProcessor.java

@@ -2,7 +2,7 @@ package envoy.server.processors;
 
 import java.io.IOException;
 
-import envoy.event.NameChangeEvent;
+import envoy.event.NameChange;
 import envoy.server.data.Contact;
 import envoy.server.data.PersistenceManager;
 import envoy.server.data.User;
@@ -17,20 +17,20 @@ import envoy.server.net.ObjectWriteProxy;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-beta
  */
-public class NameChangeProcessor implements ObjectProcessor<NameChangeEvent> {
+public class NameChangeProcessor implements ObjectProcessor<NameChange> {
 
 	@Override
-	public void process(NameChangeEvent input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(NameChange nameChange, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 		ConnectionManager	connectionManager	= ConnectionManager.getInstance();
-		Contact				toUpdate			= persistenceManager.getContactByID(input.getID());
+		Contact				toUpdate			= persistenceManager.getContactByID(nameChange.getID());
-		toUpdate.setName(input.get());
+		toUpdate.setName(nameChange.get());
 		persistenceManager.updateContact(toUpdate);
 
-		// notifying online contacts of this client of his name change
+		// Notify online contacts of the name change
-		toUpdate.getContacts().stream().filter(contact -> (contact instanceof User && connectionManager.isOnline(contact.getID()))).forEach(user -> {
+		toUpdate.getContacts().stream().filter(User.class::isInstance).map(Contact::getID).filter(connectionManager::isOnline).forEach(userID -> {
 			try {
-				writeProxy.write(user.getID(), input);
+				writeProxy.write(userID, nameChange);
 			} catch (IOException e) {
 				e.printStackTrace();
 			}
@@ -38,5 +38,5 @@ public class NameChangeProcessor implements ObjectProcessor<NameChangeEvent> {
 	}
 
 	@Override
-	public Class<NameChangeEvent> getInputClass() { return NameChangeEvent.class; }
+	public Class<NameChange> getInputClass() { return NameChange.class; }
 }

src/main/java/envoy/server/processors/UserStatusChangeProcessor.java

@@ -4,7 +4,7 @@ import java.io.IOException;
 import java.util.logging.Logger;
 
 import envoy.data.User.UserStatus;
-import envoy.event.UserStatusChangeEvent;
+import envoy.event.UserStatusChange;
 import envoy.server.data.PersistenceManager;
 import envoy.server.data.User;
 import envoy.server.net.ConnectionManager;
@@ -12,7 +12,7 @@ import envoy.server.net.ObjectWriteProxy;
 import envoy.util.EnvoyLog;
 
 /**
- * This processor handles incoming {@link UserStatusChangeEvent}.<br>
+ * This processor handles incoming {@link UserStatusChange}.<br>
  * <br>
  * Project: <strong>envoy-server-standalone</strong><br>
  * File: <strong>UserStatusChangeProcessor.java</strong><br>
@@ -21,7 +21,7 @@ import envoy.util.EnvoyLog;
  * @author Leon Hofmeister
  * @since Envoy Server Standalone v0.1-alpha
  */
-public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChangeEvent> {
+public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChange> {
 
 	private static ObjectWriteProxy		writeProxy;
 	private static PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
@@ -29,13 +29,13 @@ public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChan
 	private static final Logger logger = EnvoyLog.getLogger(UserStatusChangeProcessor.class);
 
 	@Override
-	public Class<UserStatusChangeEvent> getInputClass() { return UserStatusChangeEvent.class; }
+	public Class<UserStatusChange> getInputClass() { return UserStatusChange.class; }
 
 	@Override
-	public void process(UserStatusChangeEvent input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
+	public void process(UserStatusChange input, long socketID, ObjectWriteProxy writeProxy) throws IOException {
 		// new status should not equal old status
 		if (input.get().equals(persistenceManager.getUserByID(input.getID()).getStatus())) {
-			logger.warning("Received an unnecessary UserStatusChangeEvent");
+			logger.warning("Received an unnecessary UserStatusChange");
 			return;
 		}
 		updateUserStatus(input);
@@ -45,7 +45,7 @@ public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChan
 	 * Sets the {@link UserStatus} for a given user. Both offline contacts and
 	 * currently online contacts are notified.
 	 *
-	 * @param user the {@link UserStatusChangeEvent} that signals the change
+	 * @param user the {@link UserStatusChange} that signals the change
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 
@@ -59,10 +59,10 @@ public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChan
 	}
 
 	/**
-	 * @param evt the {@link UserStatusChangeEvent}
+	 * @param evt the {@link UserStatusChange}
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public static void updateUserStatus(UserStatusChangeEvent evt) { updateUserStatus(persistenceManager.getUserByID(evt.getID())); }
+	public static void updateUserStatus(UserStatusChange evt) { updateUserStatus(persistenceManager.getUserByID(evt.getID())); }
 
 	/**
 	 * notifies active contacts of this {@link User} that his {@link UserStatus} has
@@ -72,11 +72,11 @@ public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChan
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	private static void notifyContacts(User user) {
-		UserStatusChangeEvent	evt					= new UserStatusChangeEvent(user.getID(), user.getStatus());
+		UserStatusChange	evt					= new UserStatusChange(user.getID(), user.getStatus());
 		ConnectionManager		connectionManager	= ConnectionManager.getInstance();
 		try {
 			for (envoy.server.data.Contact contact : user.getContacts())
-				if (connectionManager.isOnline(contact.getID())) writeProxy.write(connectionManager.getSocketId(contact.getID()), evt);
+				if (connectionManager.isOnline(contact.getID())) writeProxy.write(connectionManager.getSocketID(contact.getID()), evt);
 		} catch (IOException e) {
 			e.printStackTrace();
 			logger.warning("Could not notify online contacts of user " + evt.getID() + " that his status has been changed");