Some refactorings based on suggestions from @delvh

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

@@ -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/net/ConnectionManager.java

@@ -1,10 +1,6 @@
 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 java.util.stream.Collectors;
 
 import com.jenkov.nioserver.ISocketIdListener;
@@ -53,7 +49,7 @@ 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());
 			UserStatusChangeProcessor.updateUserStatus(user);
@@ -83,14 +79,14 @@ 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 +104,6 @@ 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/processors/ContactOperationProcessor.java

@@ -27,15 +27,15 @@ public class ContactOperationProcessor implements ObjectProcessor<ContactOperati
 	public void process(ContactOperationEvent 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));
 				break;
 			default:

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

@@ -30,15 +30,15 @@ public class GroupCreationProcessor implements ObjectProcessor<GroupCreationEven
 		group.setName(input.get());
 		group.setContacts(new HashSet<>());
 		input.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));

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

@@ -31,10 +31,8 @@ public class GroupMessageProcessor implements ObjectProcessor<GroupMessage> {
 		ConnectionManager connectionManager = ConnectionManager.getInstance();
 
 		final var members = PersistenceManager.getInstance().getGroupByID(groupMessage.getRecipientID()).getContacts();
-		for (long i = 0; i < groupMessage.getMemberStatuses().size(); i++) {
+		groupMessage.getMemberStatuses().replaceAll((id, oldStatus) -> MessageStatus.SENT);
-			groupMessage.getMemberStatuses().replace(i, MessageStatus.SENT);
+		members.forEach(user -> setMemberStatus(connectionManager, groupMessage, user.getID()));
-		}
-		members.forEach(user -> { setMemberStatus(connectionManager, groupMessage, user.getID()); });
 
 		// Checks if all memberMessageStatuses are RECEIVED and if so sets the
 		// groupMessage Status to RECEIVED.
@@ -51,7 +49,7 @@ 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

@@ -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);

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

@@ -69,7 +69,7 @@ public class LoginCredentialProcessor implements ObjectProcessor<LoginCredential
 				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);
+					writeProxy.write(connectionManager.getSocketID(msg.getSender().getID()), evt);
 				}
 				PersistenceManager.getInstance().updateMessage(msg);
 			} else {

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

@@ -8,7 +8,6 @@ import javax.persistence.EntityExistsException;
 
 import envoy.data.Message;
 import envoy.data.Message.MessageStatus;
-import envoy.event.MessageStatusChangeEvent;
 import envoy.server.data.PersistenceManager;
 import envoy.server.net.ConnectionManager;
 import envoy.server.net.ObjectWriteProxy;
@@ -31,7 +30,7 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 
 	@Override
 	public void process(Message message, long socketID, ObjectWriteProxy writeProxy) {
-		if (message.getStatus!=MessageStatus.WAITING) {
+		if (message.getStatus() != MessageStatus.WAITING) {
 			logger.warning("Received message with invalid status: " + message);
 			return;
 		}
@@ -49,7 +48,7 @@ public class MessageProcessor implements ObjectProcessor<Message> {
 	private void sendToUser(ConnectionManager connectionManager, Message message, ObjectWriteProxy writeProxy) {
 		if (connectionManager.isOnline(message.getRecipientID())) try {
 			// If recipient is online, send the message directly
-			writeProxy.write(connectionManager.getSocketId(message.getRecipientID()), message);
+			writeProxy.write(connectionManager.getSocketID(message.getRecipientID()), message);
 			// Update the message status to RECEIVED
 			message.setReceivedDate(new Date());
 			message.nextStatus();

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

@@ -34,7 +34,7 @@ public class MessageStatusChangeProcessor implements ObjectProcessor<MessageStat
 
 		// 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), input);
 	}
 
 	@Override

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

@@ -76,7 +76,7 @@ public class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChan
 		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");

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

@@ -24,4 +24,4 @@
 
 		</properties>
 	</persistence-unit>
-</persistence>
+</persistence>