Shorten event names, refactor, prepare compatibility verification

pom.xml

@@ -28,7 +28,7 @@
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>
 			<artifactId>envoy-common</artifactId>
-			<version>develop-SNAPSHOT</version>
+			<version>f~compatibility_verification-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>

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

@@ -29,6 +29,20 @@ import envoy.util.EnvoyLog;
  */
 public class Startup {
 
+	/**
+	 * 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";
+
 	/**
 	 * Initializes the logger with a new config instance.
 	 * 

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

@@ -1,6 +1,6 @@
 package envoy.server.data;
 
-import java.util.Date;
+import java.time.LocalDateTime;
 import java.util.Set;
 
 import javax.persistence.*;
@@ -28,8 +28,7 @@ public abstract class Contact {
 	protected String	name;
 
 	@Column(name = "creation_date")
-	@Temporal(TemporalType.TIMESTAMP)
+	private LocalDateTime creationDate;
-	private Date creationDate;
 
 	@ManyToMany(fetch = FetchType.EAGER)
 	protected Set<Contact> contacts;
@@ -95,17 +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/Message.java

@@ -1,9 +1,10 @@
 package envoy.server.data;
 
-import java.util.Date;
+import java.time.LocalDateTime;
 
 import javax.persistence.*;
 
+import envoy.data.Message.MessageStatus;
 import envoy.data.MessageBuilder;
 
 /**
@@ -50,16 +51,13 @@ public class Message {
 	protected Contact recipient;
 
 	@Column(name = "creation_date")
-	@Temporal(TemporalType.TIMESTAMP)
+	protected LocalDateTime creationDate;
-	protected Date creationDate;
 
 	@Column(name = "received_date")
-	@Temporal(TemporalType.TIMESTAMP)
+	protected LocalDateTime receivedDate;
-	protected Date receivedDate;
 
 	@Column(name = "read_date")
-	@Temporal(TemporalType.TIMESTAMP)
+	protected LocalDateTime readDate;
-	protected Date readDate;
 
 	protected String							text;
 	protected envoy.data.Message.MessageStatus	status;
@@ -113,6 +111,11 @@ public class Message {
 		return message;
 	}
 
+	public void received() {
+		receivedDate	= LocalDateTime.now();
+		status			= MessageStatus.RECEIVED;
+	}
+
 	/**
 	 * @return the id of a {link envoy.data.Message}
 	 * @since Envoy Server Standalone v0.1-alpha
@@ -156,41 +159,41 @@ 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();
 		}));
 	}

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;
 
@@ -66,22 +66,15 @@ public class User extends Contact {
 	private byte[] passwordHash;
 
 	@Column(name = "last_seen")
-	@Temporal(TemporalType.TIMESTAMP)
+	private LocalDateTime lastSeen;
-	private Date 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()); }
 
@@ -101,13 +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

@@ -1,5 +1,6 @@
 package envoy.server.net;
 
+import java.time.LocalDateTime;
 import java.util.*;
 import java.util.stream.Collectors;
 
@@ -51,7 +52,7 @@ public class ConnectionManager implements ISocketIdListener {
 			// Notify contacts of this users offline-going
 			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

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;
@@ -18,13 +18,13 @@ 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);
@@ -36,7 +36,7 @@ public class ContactOperationProcessor implements ObjectProcessor<ContactOperati
 				// Notify the contact if online
 				if (ConnectionManager.getInstance().isOnline(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/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;
@@ -19,17 +19,17 @@ 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().forEach(c -> c.getContacts().add(group));
 		group.getContacts().add(persistenceManager.getUserByID(connectionManager.getUserIdBySocketID(socketID)));
@@ -41,7 +41,7 @@ public class GroupCreationProcessor implements ObjectProcessor<GroupCreationEven
 			.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/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;
 		}
 
@@ -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

@@ -1,19 +1,23 @@
 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 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.server.Startup;
-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.EnvoyLog;
@@ -29,126 +33,98 @@ 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();
 
 	private static final Logger logger = EnvoyLog.getLogger(LoginCredentialProcessor.class);
+	// private static final Pattern versionPattern =
+	// Pattern.compile("v(?<major>\\d).(?<minor>\\d)(?:-(?<suffix>\\w+))?");
 
 	@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);
+		// TODO: Verify compatibility
-
+		if (Startup.MIN_CLIENT_VERSION.compareTo(credentials.getClientVersion()) <= 0
-		// Not logged in successfully
+				&& Startup.MAX_CLIENT_VERSION.compareTo(credentials.getClientVersion()) >= 0) {
-		if (user == null) {
+			// writeProxy.write(socketID, new HandshakeRejectionEvent("Wrong version"));
-			logger.info("Rejecting handshake on socket " + socketID);
+			// return;
-			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 {
+			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(INTERNAL_ERROR));
+				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, msgCommon);
-				writeProxy.write(socketID, msg.toCommon());
+				msg.received();
-				msg.setReceivedDate(new Date());
+				if (connectionManager.isOnline(msg.getSender().getID()))
-				msg.setStatus(MessageStatus.RECEIVED);
+					writeProxy.write(connectionManager.getSocketID(msg.getSender().getID()), new MessageStatusChange(msgCommon));
-				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 {
+			} else writeProxy.write(socketID, new MessageStatusChange(msgCommon));
-				var evt = new MessageStatusChangeEvent(msg.toCommon());
+		}
-				logger.info("Sending messageStatusChangeEvent " + evt);
-				writeProxy.write(socketID, evt);
-			}
 	}
 
 	@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

@@ -1,7 +1,7 @@
 package envoy.server.processors;
 
 import java.io.IOException;
-import java.util.Date;
+import java.time.LocalDateTime;
 import java.util.logging.Logger;
 
 import javax.persistence.EntityExistsException;
@@ -50,7 +50,7 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 			// If recipient is online, send the message directly
 			writeProxy.write(connectionManager.getSocketID(message.getRecipientID()), message);
 			// Update the message status to RECEIVED
-			message.setReceivedDate(new Date());
+			message.setReceivedDate(LocalDateTime.now());
 			message.nextStatus();
 		} catch (IOException e) {
 			logger.warning("Recipient online. Failed to send message" + message.getID());

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 +17,26 @@ 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.setStatus(statusChange.get());
-		msg.setReadDate(input.getDate());
+		msg.setReadDate(statusChange.getDate());
 		persistenceManager.updateMessage(msg);
 
 		// Notifies the sender of the message about the status-update to READ
 		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
@@ -72,7 +72,7 @@ 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())