Merge pull request #27 from informatik-ag-ngl/f/reject_handshake

Produce HandshakeRejectionEvents

.settings/org.eclipse.jdt.core.prefs

@@ -1,4 +1,13 @@
 eclipse.preferences.version=1
+org.eclipse.jdt.core.compiler.annotation.inheritNullAnnotations=disabled
+org.eclipse.jdt.core.compiler.annotation.missingNonNullByDefaultAnnotation=ignore
+org.eclipse.jdt.core.compiler.annotation.nonnull=org.eclipse.jdt.annotation.NonNull
+org.eclipse.jdt.core.compiler.annotation.nonnull.secondary=
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault=org.eclipse.jdt.annotation.NonNullByDefault
+org.eclipse.jdt.core.compiler.annotation.nonnullbydefault.secondary=
+org.eclipse.jdt.core.compiler.annotation.nullable=org.eclipse.jdt.annotation.Nullable
+org.eclipse.jdt.core.compiler.annotation.nullable.secondary=
+org.eclipse.jdt.core.compiler.annotation.nullanalysis=disabled
 org.eclipse.jdt.core.compiler.codegen.inlineJsrBytecode=enabled
 org.eclipse.jdt.core.compiler.codegen.targetPlatform=1.8
 org.eclipse.jdt.core.compiler.codegen.unusedLocal=preserve
@@ -6,10 +15,101 @@ org.eclipse.jdt.core.compiler.compliance=1.8
 org.eclipse.jdt.core.compiler.debug.lineNumber=generate
 org.eclipse.jdt.core.compiler.debug.localVariable=generate
 org.eclipse.jdt.core.compiler.debug.sourceFile=generate
+org.eclipse.jdt.core.compiler.problem.APILeak=warning
+org.eclipse.jdt.core.compiler.problem.annotationSuperInterface=warning
 org.eclipse.jdt.core.compiler.problem.assertIdentifier=error
+org.eclipse.jdt.core.compiler.problem.autoboxing=ignore
+org.eclipse.jdt.core.compiler.problem.comparingIdentical=warning
+org.eclipse.jdt.core.compiler.problem.deadCode=warning
+org.eclipse.jdt.core.compiler.problem.deprecation=warning
+org.eclipse.jdt.core.compiler.problem.deprecationInDeprecatedCode=disabled
+org.eclipse.jdt.core.compiler.problem.deprecationWhenOverridingDeprecatedMethod=disabled
+org.eclipse.jdt.core.compiler.problem.discouragedReference=warning
+org.eclipse.jdt.core.compiler.problem.emptyStatement=info
 org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
+org.eclipse.jdt.core.compiler.problem.explicitlyClosedAutoCloseable=warning
+org.eclipse.jdt.core.compiler.problem.fallthroughCase=ignore
+org.eclipse.jdt.core.compiler.problem.fatalOptionalError=disabled
+org.eclipse.jdt.core.compiler.problem.fieldHiding=ignore
+org.eclipse.jdt.core.compiler.problem.finalParameterBound=warning
+org.eclipse.jdt.core.compiler.problem.finallyBlockNotCompletingNormally=warning
 org.eclipse.jdt.core.compiler.problem.forbiddenReference=warning
+org.eclipse.jdt.core.compiler.problem.hiddenCatchBlock=warning
+org.eclipse.jdt.core.compiler.problem.includeNullInfoFromAsserts=disabled
+org.eclipse.jdt.core.compiler.problem.incompatibleNonInheritedInterfaceMethod=warning
+org.eclipse.jdt.core.compiler.problem.incompleteEnumSwitch=ignore
+org.eclipse.jdt.core.compiler.problem.indirectStaticAccess=warning
+org.eclipse.jdt.core.compiler.problem.localVariableHiding=ignore
+org.eclipse.jdt.core.compiler.problem.methodWithConstructorName=warning
+org.eclipse.jdt.core.compiler.problem.missingDefaultCase=ignore
+org.eclipse.jdt.core.compiler.problem.missingDeprecatedAnnotation=ignore
+org.eclipse.jdt.core.compiler.problem.missingEnumCaseDespiteDefault=disabled
+org.eclipse.jdt.core.compiler.problem.missingHashCodeMethod=ignore
+org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotation=warning
+org.eclipse.jdt.core.compiler.problem.missingOverrideAnnotationForInterfaceMethodImplementation=enabled
+org.eclipse.jdt.core.compiler.problem.missingSerialVersion=warning
+org.eclipse.jdt.core.compiler.problem.missingSynchronizedOnInheritedMethod=ignore
+org.eclipse.jdt.core.compiler.problem.noEffectAssignment=warning
+org.eclipse.jdt.core.compiler.problem.noImplicitStringConversion=warning
+org.eclipse.jdt.core.compiler.problem.nonExternalizedStringLiteral=ignore
+org.eclipse.jdt.core.compiler.problem.nonnullParameterAnnotationDropped=warning
+org.eclipse.jdt.core.compiler.problem.nonnullTypeVariableFromLegacyInvocation=warning
+org.eclipse.jdt.core.compiler.problem.nullAnnotationInferenceConflict=error
+org.eclipse.jdt.core.compiler.problem.nullReference=warning
+org.eclipse.jdt.core.compiler.problem.nullSpecViolation=error
+org.eclipse.jdt.core.compiler.problem.nullUncheckedConversion=warning
+org.eclipse.jdt.core.compiler.problem.overridingPackageDefaultMethod=warning
+org.eclipse.jdt.core.compiler.problem.parameterAssignment=ignore
+org.eclipse.jdt.core.compiler.problem.pessimisticNullAnalysisForFreeTypeVariables=warning
+org.eclipse.jdt.core.compiler.problem.possibleAccidentalBooleanAssignment=ignore
+org.eclipse.jdt.core.compiler.problem.potentialNullReference=ignore
+org.eclipse.jdt.core.compiler.problem.potentiallyUnclosedCloseable=ignore
+org.eclipse.jdt.core.compiler.problem.rawTypeReference=warning
+org.eclipse.jdt.core.compiler.problem.redundantNullAnnotation=warning
+org.eclipse.jdt.core.compiler.problem.redundantNullCheck=warning
+org.eclipse.jdt.core.compiler.problem.redundantSpecificationOfTypeArguments=warning
+org.eclipse.jdt.core.compiler.problem.redundantSuperinterface=warning
+org.eclipse.jdt.core.compiler.problem.reportMethodCanBePotentiallyStatic=ignore
+org.eclipse.jdt.core.compiler.problem.reportMethodCanBeStatic=ignore
 org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=ignore
+org.eclipse.jdt.core.compiler.problem.specialParameterHidingField=disabled
+org.eclipse.jdt.core.compiler.problem.staticAccessReceiver=warning
+org.eclipse.jdt.core.compiler.problem.suppressOptionalErrors=disabled
+org.eclipse.jdt.core.compiler.problem.suppressWarnings=enabled
+org.eclipse.jdt.core.compiler.problem.suppressWarningsNotFullyAnalysed=info
+org.eclipse.jdt.core.compiler.problem.syntacticNullAnalysisForFields=disabled
+org.eclipse.jdt.core.compiler.problem.syntheticAccessEmulation=ignore
+org.eclipse.jdt.core.compiler.problem.terminalDeprecation=warning
+org.eclipse.jdt.core.compiler.problem.typeParameterHiding=warning
+org.eclipse.jdt.core.compiler.problem.unavoidableGenericTypeProblems=disabled
+org.eclipse.jdt.core.compiler.problem.uncheckedTypeOperation=warning
+org.eclipse.jdt.core.compiler.problem.unclosedCloseable=warning
+org.eclipse.jdt.core.compiler.problem.undocumentedEmptyBlock=ignore
+org.eclipse.jdt.core.compiler.problem.unhandledWarningToken=warning
+org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentType=warning
+org.eclipse.jdt.core.compiler.problem.unlikelyCollectionMethodArgumentTypeStrict=disabled
+org.eclipse.jdt.core.compiler.problem.unlikelyEqualsArgumentType=info
+org.eclipse.jdt.core.compiler.problem.unnecessaryElse=warning
+org.eclipse.jdt.core.compiler.problem.unnecessaryTypeCheck=warning
+org.eclipse.jdt.core.compiler.problem.unqualifiedFieldAccess=ignore
+org.eclipse.jdt.core.compiler.problem.unstableAutoModuleName=warning
+org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownException=warning
+org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionExemptExceptionAndThrowable=enabled
+org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionIncludeDocCommentReference=enabled
+org.eclipse.jdt.core.compiler.problem.unusedDeclaredThrownExceptionWhenOverriding=disabled
+org.eclipse.jdt.core.compiler.problem.unusedExceptionParameter=ignore
+org.eclipse.jdt.core.compiler.problem.unusedImport=warning
+org.eclipse.jdt.core.compiler.problem.unusedLabel=warning
+org.eclipse.jdt.core.compiler.problem.unusedLocal=warning
+org.eclipse.jdt.core.compiler.problem.unusedObjectAllocation=ignore
+org.eclipse.jdt.core.compiler.problem.unusedParameter=warning
+org.eclipse.jdt.core.compiler.problem.unusedParameterIncludeDocCommentReference=enabled
+org.eclipse.jdt.core.compiler.problem.unusedParameterWhenImplementingAbstract=disabled
+org.eclipse.jdt.core.compiler.problem.unusedParameterWhenOverridingConcrete=disabled
+org.eclipse.jdt.core.compiler.problem.unusedPrivateMember=warning
+org.eclipse.jdt.core.compiler.problem.unusedTypeParameter=warning
+org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning
+org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
 org.eclipse.jdt.core.compiler.release=disabled
 org.eclipse.jdt.core.compiler.source=1.8

pom.xml

@@ -28,12 +28,12 @@
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>
 			<artifactId>envoy-common</artifactId>
-			<version>develop-SNAPSHOT</version>
+			<version>v0.2-alpha</version>
 		</dependency>
 		<dependency>
 			<groupId>com.github.informatik-ag-ngl</groupId>
 			<artifactId>java-nio-server</artifactId>
-			<version>master-SNAPSHOT</version>
+			<version>v0.1-alpha</version>
 		</dependency>
 		<dependency>
 			<groupId>org.hibernate</groupId>
@@ -54,5 +54,30 @@
 				<directory>src/main/resources</directory>
 			</resource>
 		</resources>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-assembly-plugin</artifactId>
+				<version>2.4.1</version>
+				<executions>
+					<execution>
+						<phase>package</phase>
+						<goals>
+							<goal>single</goal>
+						</goals>
+						<configuration>
+							<archive>
+								<manifest>
+									<mainClass>envoy.server.Startup</mainClass>
+								</manifest>
+							</archive>
+							<descriptorRefs>
+								<descriptorRef>jar-with-dependencies</descriptorRef>
+							</descriptorRefs>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
 	</build>
 </project>

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

@@ -8,6 +8,7 @@ import com.jenkov.nioserver.Server;
 
 import envoy.server.data.ConfigItem;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectMessageProcessor;
 import envoy.server.net.ObjectMessageReader;
 import envoy.server.processors.*;
@@ -53,7 +54,7 @@ public class Startup {
 	}
 
 	private static void initializeCurrentMessageId() {
-		PersistenceManager persMan = PersistenceManager.getPersistenceManager();
+		PersistenceManager persMan = PersistenceManager.getInstance();
 		if (persMan.getConfigItemById("currentMessageId") == null) persMan.addConfigItem(new ConfigItem("currentMessageId", "0"));
 	}
 }

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

@@ -66,7 +66,7 @@ public class Message {
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	public Message(envoy.data.Message message) {
-		PersistenceManager persMan = PersistenceManager.getPersistenceManager();
+		PersistenceManager persMan = PersistenceManager.getInstance();
 		id				= message.getId();
 		status			= message.getStatus();
 		text			= message.getText();

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

@@ -1,14 +1,17 @@
 package envoy.server.database;
 
+import java.util.Date;
 import java.util.List;
 
 import javax.persistence.EntityManager;
 import javax.persistence.EntityTransaction;
 import javax.persistence.Persistence;
 
+import envoy.data.User.UserStatus;
 import envoy.server.data.ConfigItem;
 import envoy.server.data.Message;
 import envoy.server.data.User;
+import envoy.server.net.ConnectionManager;
 
 /**
  * Project: <strong>envoy-server-standalone</strong><br>
@@ -32,14 +35,21 @@ public class PersistenceManager {
 	 */
 	private PersistenceManager() {
 		transaction.begin();
-		Runtime.getRuntime().addShutdownHook(new Thread(() -> transaction.commit()));
+		Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+			ConnectionManager.getInstance()
+				.getOnlineUsers()
+				.stream()
+				.map(this::getUserById)
+				.forEach(user -> { user.setStatus(UserStatus.OFFLINE); user.setLastSeen(new Date()); updateUser(user); });
+			transaction.commit();
+		}));
 	}
 
 	/**
 	 * @return the {@link PersistenceManager} singleton
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
-	public static PersistenceManager getPersistenceManager() { return persistenceManager; }
+	public static PersistenceManager getInstance() { return persistenceManager; }
 
 	/**
 	 * Adds a {@link User} to the database.

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

@@ -1,10 +1,6 @@
-package envoy.server;
+package envoy.server.net;
 
-import java.util.Date;
+import java.util.*;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
 
 import com.jenkov.nioserver.ISocketIdListener;
 
@@ -50,14 +46,14 @@ public class ConnectionManager implements ISocketIdListener {
 	@Override
 	public void socketCancelled(long socketId) {
 		if (!pendingSockets.remove(socketId)) {
-			// notifying contacts of this users offline-going
+			// Notify contacts of this users offline-going
-			envoy.server.data.User user = PersistenceManager.getPersistenceManager().getUserById(getUserIdBySocketId(socketId));
+			envoy.server.data.User user = PersistenceManager.getInstance().getUserById(getUserIdBySocketId(socketId));
 			user.setStatus(UserStatus.OFFLINE);
 			user.setLastSeen(new Date());
 			UserStatusChangeProcessor.updateUserStatus(user);
 
-			// removing the socket
+			// Remove the socket
-			sockets.entrySet().stream().filter(e -> e.getValue() == socketId).forEach(e -> sockets.remove(e.getValue()));
+			sockets.entrySet().removeIf(e -> e.getValue() == socketId);
 		}
 	}
 
@@ -98,4 +94,10 @@ public class ConnectionManager implements ISocketIdListener {
 	 * @since Envoy Server Standalone v0.1-alpha
 	 */
 	public boolean isOnline(long userId) { return sockets.containsKey(userId); }
+
+	/**
+	 * @return the userId of all users who are currently online
+	 * @since Envoy Server Standalone v0.1-alpha
+	 */
+	public Set<Long> getOnlineUsers() { return sockets.keySet(); }
 }

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

@@ -5,9 +5,9 @@ import java.util.Arrays;
 
 import envoy.data.Contacts;
 import envoy.event.ContactOperationEvent;
-import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -30,11 +30,11 @@ public class ContactOperationProcessor implements ObjectProcessor<ContactOperati
 				final long contactId = evt.get().getId();
 
 				System.out.printf("Adding user %s to the contact list of user %d.%n", evt.get(), userId);
-				PersistenceManager.getPersistenceManager().addContact(userId, contactId);
+				PersistenceManager.getInstance().addContact(userId, contactId);
 
 				// Notify the contact if online
 				if (ConnectionManager.getInstance().isOnline(contactId)) writeProxy.write(connectionManager.getSocketId(contactId),
-						new Contacts(Arrays.asList(PersistenceManager.getPersistenceManager().getUserById(userId).toCommonUser())));
+						new Contacts(Arrays.asList(PersistenceManager.getInstance().getUserById(userId).toCommonUser())));
 				break;
 			default:
 				System.err.printf("Received %s with an unsupported operation.%n", evt);

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

@@ -6,10 +6,10 @@ import java.util.stream.Collectors;
 import envoy.data.Contacts;
 import envoy.event.ContactSearchRequest;
 import envoy.event.ContactSearchResult;
-import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.data.User;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -33,7 +33,7 @@ public class ContactsRequestEventProcessor implements ObjectProcessor<ContactSea
 	@Override
 	public void process(ContactSearchRequest request, long socketId, ObjectWriteProxy writeProxy) throws IOException {
 		writeProxy.write(socketId,
-				new ContactSearchResult(PersistenceManager.getPersistenceManager()
+				new ContactSearchResult(PersistenceManager.getInstance()
 					.searchUsers(request.get(), ConnectionManager.getInstance().getUserIdBySocketId(socketId))
 					.stream()
 					.map(User::toCommonUser)

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

@@ -19,7 +19,7 @@ import envoy.server.net.ObjectWriteProxy;
  */
 public class IdGeneratorRequestProcessor implements ObjectProcessor<IdGeneratorRequest> {
 
-	private static final long ID_RANGE = 2;
+	private static final long ID_RANGE = 200;
 
 	@Override
 	public Class<IdGeneratorRequest> getInputClass() { return IdGeneratorRequest.class; }
@@ -28,10 +28,10 @@ public class IdGeneratorRequestProcessor implements ObjectProcessor<IdGeneratorR
 	public void process(IdGeneratorRequest input, long socketId, ObjectWriteProxy writeProxy) throws IOException {
 		System.out.println("Received id generation request.");
 
-		ConfigItem	currentId	= PersistenceManager.getPersistenceManager().getConfigItemById("currentMessageId");
+		ConfigItem	currentId	= PersistenceManager.getInstance().getConfigItemById("currentMessageId");
 		IdGenerator	generator	= new IdGenerator(Integer.parseInt(currentId.getValue()), ID_RANGE);
 		currentId.setValue(String.valueOf(Integer.parseInt(currentId.getValue()) + ID_RANGE));
-		PersistenceManager.getPersistenceManager().updateConfigItem(currentId);
+		PersistenceManager.getInstance().updateConfigItem(currentId);
 
 		System.out.println("Sending new id generator " + generator);
 		writeProxy.write(socketId, generator);

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

@@ -4,15 +4,18 @@ import java.io.IOException;
 import java.util.*;
 import java.util.stream.Collectors;
 
+import javax.persistence.NoResultException;
+
 import envoy.data.Contacts;
 import envoy.data.LoginCredentials;
 import envoy.data.Message.MessageStatus;
 import envoy.data.User;
 import envoy.data.User.UserStatus;
-import envoy.server.ConnectionManager;
+import envoy.event.HandshakeRejectionEvent;
 import envoy.server.ObjectProcessor;
 import envoy.server.data.Message;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -28,23 +31,24 @@ import envoy.server.net.ObjectWriteProxy;
  */
 public class LoginCredentialProcessor implements ObjectProcessor<LoginCredentials> {
 
-	private PersistenceManager persistenceManager = PersistenceManager.getPersistenceManager();
+	private final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
-
+	private final ConnectionManager		connectionManager	= ConnectionManager.getInstance();
-	@Override
-	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
 
 	@Override
 	public void process(LoginCredentials input, long socketId, ObjectWriteProxy writeProxy) throws IOException {
 		UserStatusChangeProcessor.setWriteProxy(writeProxy);
 		System.out.println(String.format("Received login credentials %s from socket ID %d", input, socketId));
 
-		envoy.server.data.User user = getUser(input);
+		envoy.server.data.User user = getUser(input, socketId, writeProxy);
 
 		// Not logged in successfully
-		if (user == null) return;
+		if (user == null) {
-		ConnectionManager.getInstance().registerUser(user.getId(), socketId);
+			System.out.println("Rejecting handshake on socket " + socketId);
+			return;
+		}
+		connectionManager.registerUser(user.getId(), socketId);
 
-		// notifies contacts of this users online-going and updates his status in the
+		// Notifies contacts of this users online-going and updates his status in the
 		// database
 		user.setStatus(UserStatus.ONLINE);
 		UserStatusChangeProcessor.updateUserStatus(user);
@@ -59,33 +63,86 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 		System.out.println("Sending contacts...");
 		writeProxy.write(socketId, contacts);
 		System.out.println("Acquiring pending messages for the client...");
-		List<Message> pendingMessages = PersistenceManager.getPersistenceManager().getUnreadMessages(user);
+		List<Message> pendingMessages = PersistenceManager.getInstance().getUnreadMessages(user);
 		for (Message msg : pendingMessages) {
-			System.out.println("Sending message " + msg.toCommonMessage().toString());
+			System.out.println("Sending message " + msg.toCommonMessage());
 			writeProxy.write(socketId, msg.toCommonMessage());
 			msg.setReceivedDate(new Date());
 			msg.setStatus(MessageStatus.RECEIVED);
-			PersistenceManager.getPersistenceManager().updateMessage(msg);
+			PersistenceManager.getInstance().updateMessage(msg);
 		}
 	}
 
-	private envoy.server.data.User getUser(LoginCredentials credentials) {
+	@Override
-		envoy.server.data.User user;
+	public Class<LoginCredentials> getInputClass() { return LoginCredentials.class; }
 
-		if (credentials.isRegistration()) {
+	private envoy.server.data.User getUser(LoginCredentials credentials, long socketId, ObjectWriteProxy writeProxy) throws IOException {
-			user = new envoy.server.data.User();
+		return credentials.isRegistration() ? newUser(credentials, socketId, writeProxy) : checkForExistingUser(credentials, socketId, writeProxy);
-			user.setName(credentials.getName());
+	}
-			user.setLastSeen(new Date());
+
-			user.setStatus(User.UserStatus.ONLINE);
+	/**
-			user.setPasswordHash(credentials.getPasswordHash());
+	 * @param credentials the input to evaluate
-			persistenceManager.addUser(user);
+	 * @param socketId    the socket ID at which the client performing the handshake
-			user.setContacts(new ArrayList<>());
+	 *                    is connected
-		} else {
+	 * @param writeProxy  the {@link ObjectWriteProxy} to use if login was not
-			user = persistenceManager.getUserByName(credentials.getName());
+	 *                    successful
-			// TODO: Implement error when user does not exist
+	 * @return the database user matching the login credentials
-			if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) // TODO: Wrong Password Response
+	 * @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.ALREADY_ONLINE));
+				return null;
+			}
+			// Evaluating the correctness of the password hash
+			if (!Arrays.equals(credentials.getPasswordHash(), user.getPasswordHash())) {
+				writeProxy.write(socketId, new HandshakeRejectionEvent(HandshakeRejectionEvent.WRONG_PASSWORD));
 				return null;
 			}
 			return user;
+		} catch (NoResultException e) {
+			// Checking if user exists
+			writeProxy.write(socketId, new HandshakeRejectionEvent(HandshakeRejectionEvent.USER_DOES_NOT_EXIST));
+		} catch (InputMismatchException e) {
+			// Checking if the given password hash is correct
+			writeProxy.write(socketId, new HandshakeRejectionEvent(HandshakeRejectionEvent.WRONG_PASSWORD));
+		}
+		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.USER_EXISTS_ALREADY));
+			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 ArrayList<>());
+			persistenceManager.addUser(user);
+			return user;
+		}
 	}
 }

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

@@ -5,9 +5,9 @@ import java.util.Date;
 
 import envoy.data.Message;
 import envoy.event.MessageStatusChangeEvent;
-import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -37,11 +37,11 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 			// Update the message status to RECEIVED
 			message.setReceivedDate(new Date());
 			message.nextStatus();
-			writeProxy.write(connectionManager.getSocketId(message.getSenderId()), new MessageStatusChangeEvent(message));
+			writeProxy.write(socketId, new MessageStatusChangeEvent(message));
 		} catch (IOException e) {
 			System.err.println("Recipient online. Failed to send message" + message.getId());
 			e.printStackTrace();
 		}
-		PersistenceManager.getPersistenceManager().addMessage(new envoy.server.data.Message(message));
+		PersistenceManager.getInstance().addMessage(new envoy.server.data.Message(message));
 	}
 }

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

@@ -5,9 +5,9 @@ import java.io.IOException;
 import envoy.data.Message.MessageStatus;
 import envoy.event.MessageStatusChangeEvent;
 import envoy.exception.EnvoyException;
-import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -32,7 +32,7 @@ public class MessageStatusChangeProcessor implements ObjectProcessor<MessageStat
 			throw new IOException(e);
 		}
 		ConnectionManager	conMan	= ConnectionManager.getInstance();
-		PersistenceManager	perMan	= PersistenceManager.getPersistenceManager();
+		PersistenceManager	perMan	= PersistenceManager.getInstance();
 
 		envoy.server.data.Message msg = perMan.getMessageById(input.getId());
 		msg.setStatus(input.get());

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

@@ -4,10 +4,10 @@ import java.io.IOException;
 
 import envoy.data.User.UserStatus;
 import envoy.event.UserStatusChangeEvent;
-import envoy.server.ConnectionManager;
 import envoy.server.ObjectProcessor;
 import envoy.server.data.User;
 import envoy.server.database.PersistenceManager;
+import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
 
 /**
@@ -23,7 +23,7 @@ import envoy.server.net.ObjectWriteProxy;
 public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChangeEvent> {
 
 	private static ObjectWriteProxy		writeProxy;
-	private static PersistenceManager	persistenceManager	= PersistenceManager.getPersistenceManager();
+	private static PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 
 	@Override
 	public Class<UserStatusChangeEvent> getInputClass() { return UserStatusChangeEvent.class; }

src/main/resources/META-INF/persistence.xml

@@ -20,8 +20,6 @@
 				value="org.hibernate.dialect.PostgreSQL95Dialect" /> <!-- DB Dialect -->
 			<property name="hibernate.hbm2ddl.auto" value="update" /> <!-- create / create-drop / update -->
 
-			<property name="hibernate.show_sql" value="true" /> <!-- Show SQL in console -->
-			<property name="hibernate.format_sql" value="true" /> <!-- Show SQL formatted -->
 		</properties>
 
 	</persistence-unit>