Did some cleanup, removed deprecated and unused classes, added javadoc.

client/src/main/java/nl/andrewl/concord_client/event/handlers/ChannelUsersResponseHandler.java

@@ -1,16 +0,0 @@
-package nl.andrewl.concord_client.event.handlers;
-
-import nl.andrewl.concord_client.ConcordClient;
-import nl.andrewl.concord_client.event.MessageHandler;
-import nl.andrewl.concord_core.msg.types.ChannelUsersResponse;
-
-/**
- * When the client receives information about the list of known users, it will
- * update its model to show the new list.
- */
-public class ChannelUsersResponseHandler implements MessageHandler<ChannelUsersResponse> {
-	@Override
-	public void handle(ChannelUsersResponse msg, ConcordClient client) throws Exception {
-		client.getModel().setKnownUsers(msg.getUsers());
-	}
-}

core/src/main/java/nl/andrewl/concord_core/msg/Encryption.java

@@ -23,6 +23,26 @@ import java.util.List;
  * Utility class for handling the establishment of encrypted communication.
  */
 public class Encryption {
+	/**
+	 * Upgrades the given input and output streams to a pair of cipher input and
+	 * output streams. This upgrade follows the following steps:
+	 * <ol>
+	 *     <li>Generate an elliptic curve key pair, and send the public key to the output stream.</li>
+	 *     <li>Read the public key that the other person has sent, from the input stream.</li>
+	 *     <li>Compute a shared private key using the ECDH key exchange, with our private key and their public key.</li>
+	 *     <li>Create the cipher streams from the shared private key.</li>
+	 * </ol>
+	 * @param in The unencrypted input stream.
+	 * @param out The unencrypted output stream.
+	 * @param serializer The message serializer that is used to read and write
+	 *                   messages according to the standard Concord protocol.
+	 * @return The pair of cipher streams, which can be used to send encrypted
+	 * messages.
+	 * @throws GeneralSecurityException If an error occurs while generating keys
+	 * or preparing the cipher streams.
+	 * @throws IOException If an error occurs while reading or writing data on
+	 * the streams.
+	 */
 	public static Pair<CipherInputStream, CipherOutputStream> upgrade(
 			InputStream in,
 			OutputStream out,

core/src/main/java/nl/andrewl/concord_core/msg/Serializer.java

@@ -36,7 +36,7 @@ public class Serializer {
 		registerType(3, MoveToChannel.class);
 		registerType(4, ChatHistoryRequest.class);
 		registerType(5, ChatHistoryResponse.class);
-		registerType(6, ChannelUsersRequest.class);
+		// Type id 6 removed due to deprecation.
 		registerType(7, ServerUsers.class);
 		registerType(8, ServerMetaData.class);
 		registerType(9, Error.class);

core/src/main/java/nl/andrewl/concord_core/msg/types/ChannelUsersRequest.java

@@ -1,36 +0,0 @@
-package nl.andrewl.concord_core.msg.types;
-
-import lombok.AllArgsConstructor;
-import lombok.Data;
-import lombok.NoArgsConstructor;
-import nl.andrewl.concord_core.msg.Message;
-
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
-import java.io.IOException;
-import java.util.UUID;
-
-import static nl.andrewl.concord_core.msg.MessageUtils.*;
-
-@Data
-@NoArgsConstructor
-@AllArgsConstructor
-@Deprecated
-public class ChannelUsersRequest implements Message {
-	private UUID channelId;
-
-	@Override
-	public int getByteCount() {
-		return UUID_BYTES;
-	}
-
-	@Override
-	public void write(DataOutputStream o) throws IOException {
-		writeUUID(this.channelId, o);
-	}
-
-	@Override
-	public void read(DataInputStream i) throws IOException {
-		this.channelId = readUUID(i);
-	}
-}

core/src/main/java/nl/andrewl/concord_core/msg/types/ChannelUsersResponse.java

@@ -1,43 +0,0 @@
-package nl.andrewl.concord_core.msg.types;
-
-import lombok.AllArgsConstructor;
-import lombok.Data;
-import lombok.NoArgsConstructor;
-import nl.andrewl.concord_core.msg.Message;
-
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
-import java.io.IOException;
-import java.util.List;
-
-import static nl.andrewl.concord_core.msg.MessageUtils.*;
-
-/**
- * This message is sent from the server to the client when the information about
- * the users in the channel that a client is in has changed. For example, when
- * a user leaves a channel, all others in that channel will be sent this message
- * to indicate that update.
- * @deprecated Clients will be updated via a {@link ServerUsers} message.
- */
-@Data
-@NoArgsConstructor
-@AllArgsConstructor
-@Deprecated
-public class ChannelUsersResponse implements Message {
-	private List<UserData> users;
-
-	@Override
-	public int getByteCount() {
-		return getByteSize(this.users);
-	}
-
-	@Override
-	public void write(DataOutputStream o) throws IOException {
-		writeList(this.users, o);
-	}
-
-	@Override
-	public void read(DataInputStream i) throws IOException {
-		this.users = readList(UserData.class, i);
-	}
-}

core/src/main/java/nl/andrewl/concord_core/msg/types/ChatHistoryRequest.java

@@ -77,6 +77,10 @@ public class ChatHistoryRequest implements Message {
 				.collect(Collectors.joining(";"));
 	}
 
+	/**
+	 * Utility method to extract the query string's values as a key-value map.
+	 * @return A map of the query parameters.
+	 */
 	public Map<String, String> getQueryAsMap() {
 		String[] pairs = this.query.split(";");
 		if (pairs.length == 0) return Map.of();

server/src/main/java/nl/andrewl/concord_server/ConcordServer.java

@@ -145,7 +145,7 @@ public class ConcordServer implements Runnable {
 	private void shutdown() {
 		System.out.println("Shutting down the server.");
 		for (var clientId : this.clientManager.getConnectedIds()) {
-			this.clientManager.deregisterClient(clientId);
+			this.clientManager.handleLogOut(clientId);
 		}
 		this.scheduledExecutorService.shutdown();
 		this.executorService.shutdown();
@@ -161,13 +161,7 @@ public class ConcordServer implements Runnable {
 	public void run() {
 		this.running = true;
 		this.scheduledExecutorService.scheduleAtFixedRate(this.discoveryServerPublisher::publish, 0, 1, TimeUnit.MINUTES);
-		StringBuilder startupMessage = new StringBuilder();
+		System.out.printf("Opened server on port %d.\n", config.getPort());
-		startupMessage.append("Opened server on port ").append(config.getPort()).append("\n")
-				.append("The following channels are available:\n");
-		for (var channel : this.channelManager.getChannels()) {
-			startupMessage.append("\tChannel \"").append(channel).append('\n');
-		}
-		System.out.println(startupMessage);
 		while (this.running) {
 			try {
 				Socket socket = this.serverSocket.accept();

server/src/main/java/nl/andrewl/concord_server/channel/Channel.java

@@ -21,11 +21,14 @@ import java.util.concurrent.ConcurrentHashMap;
  * clients in a server.
  */
 @Getter
-public class Channel {
+public class Channel implements Comparable<Channel> {
 	private final ConcordServer server;
 	private final UUID id;
 	private String name;
 
+	/**
+	 * The set of clients that are connected to this channel.
+	 */
 	private final Set<ClientThread> connectedClients;
 
 	/**
@@ -94,6 +97,10 @@ public class Channel {
 		return users;
 	}
 
+	public String getAsTag() {
+		return "#" + this.name;
+	}
+
 	@Override
 	public boolean equals(Object o) {
 		if (this == o) return true;
@@ -111,4 +118,9 @@ public class Channel {
 	public String toString() {
 		return this.name + " (" + this.id + ")";
 	}
+
+	@Override
+	public int compareTo(Channel o) {
+		return this.getName().compareTo(o.getName());
+	}
 }

server/src/main/java/nl/andrewl/concord_server/cli/ServerCli.java

@@ -1,9 +1,8 @@
 package nl.andrewl.concord_server.cli;
 
 import nl.andrewl.concord_server.ConcordServer;
-import nl.andrewl.concord_server.cli.command.AddChannelCommand;
+import nl.andrewl.concord_server.cli.command.ChannelCommand;
 import nl.andrewl.concord_server.cli.command.ListClientsCommand;
-import nl.andrewl.concord_server.cli.command.RemoveChannelCommand;
 import nl.andrewl.concord_server.cli.command.StopCommand;
 
 import java.io.BufferedReader;
@@ -12,6 +11,10 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
 
+/**
+ * Simple command-line interface that's available when running the server. This
+ * accepts commands and various space-separated arguments.
+ */
 public class ServerCli implements Runnable {
 	private final ConcordServer server;
 	private final Map<String, ServerCliCommand> commands;
@@ -21,8 +24,7 @@ public class ServerCli implements Runnable {
 		this.commands = new HashMap<>();
 
 		this.commands.put("list-clients", new ListClientsCommand());
-		this.commands.put("add-channel", new AddChannelCommand());
+		this.commands.put("channel", new ChannelCommand());
-		this.commands.put("remove-channel", new RemoveChannelCommand());
 		this.commands.put("stop", new StopCommand());
 
 		this.commands.put("help", (s, args) -> {
@@ -35,7 +37,7 @@ public class ServerCli implements Runnable {
 
 	@Override
 	public void run() {
-		System.out.println("Server command-line-interface initialized. Type \"help\" for a list of available commands.");
+		System.out.println("Server command-line-interface initialized.\n\tType \"help\" for a list of available commands.\n\tType \"stop\" to stop the server.");
 		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
 		String line;
 		try {

server/src/main/java/nl/andrewl/concord_server/cli/command/AddChannelCommand.java

@@ -1,41 +0,0 @@
-package nl.andrewl.concord_server.cli.command;
-
-import nl.andrewl.concord_server.ConcordServer;
-import nl.andrewl.concord_server.channel.Channel;
-import nl.andrewl.concord_server.cli.ServerCliCommand;
-import nl.andrewl.concord_server.config.ServerConfig;
-
-import java.util.UUID;
-
-/**
- * This command adds a new channel to the server.
- */
-public class AddChannelCommand implements ServerCliCommand {
-	@Override
-	public void handle(ConcordServer server, String[] args) throws Exception {
-		if (args.length < 1) {
-			System.err.println("Missing required name argument.");
-			return;
-		}
-		String name = args[0].trim().toLowerCase().replaceAll("\\s+", "-");
-		if (name.isBlank()) {
-			System.err.println("Cannot create channel with blank name.");
-			return;
-		}
-		if (server.getChannelManager().getChannelByName(name).isPresent()) {
-			System.err.println("Channel with that name already exists.");
-			return;
-		}
-		String description = null;
-		if (args.length > 1) {
-			description = args[1].trim();
-		}
-		UUID id = server.getIdProvider().newId();
-		var channelConfig = new ServerConfig.ChannelConfig(id.toString(), name, description);
-		server.getConfig().getChannels().add(channelConfig);
-		server.getConfig().save();
-
-		server.getChannelManager().addChannel(new Channel(server, id, name));
-		server.getClientManager().broadcast(server.getMetaData());
-	}
-}

server/src/main/java/nl/andrewl/concord_server/cli/command/ChannelCommand.java

@@ -0,0 +1,105 @@
+package nl.andrewl.concord_server.cli.command;
+
+import nl.andrewl.concord_server.ConcordServer;
+import nl.andrewl.concord_server.channel.Channel;
+import nl.andrewl.concord_server.cli.ServerCliCommand;
+import nl.andrewl.concord_server.config.ServerConfig;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Optional;
+import java.util.UUID;
+
+/**
+ * Command for interacting with channels on the server.
+ */
+public class ChannelCommand implements ServerCliCommand {
+	@Override
+	public void handle(ConcordServer server, String[] args) throws Exception {
+		if (args.length < 1) {
+			System.err.println("Missing required subcommand. Valid subcommands are: add, remove, list");
+			return;
+		}
+		String subcommand = args[0];
+		args = Arrays.copyOfRange(args, 1, args.length);
+		switch (subcommand) {
+			case "add" -> addChannel(server, args);
+			case "remove" -> removeChannel(server, args);
+			case "list" -> listChannels(server);
+			default -> System.err.println("Unknown subcommand.");
+		}
+	}
+
+	private void addChannel(ConcordServer server, String[] args) throws IOException {
+		if (args.length < 1) {
+			System.err.println("Missing required name argument.");
+			return;
+		}
+		String name = args[0].trim().toLowerCase().replaceAll("\\s+", "-");
+		if (name.isBlank()) {
+			System.err.println("Cannot create channel with blank name.");
+			return;
+		}
+		if (server.getChannelManager().getChannelByName(name).isPresent()) {
+			System.err.println("Channel with that name already exists.");
+			return;
+		}
+		String description = null;
+		if (args.length > 1) {
+			description = args[1].trim();
+		}
+		UUID id = server.getIdProvider().newId();
+		var channelConfig = new ServerConfig.ChannelConfig(id.toString(), name, description);
+		server.getConfig().getChannels().add(channelConfig);
+		server.getConfig().save();
+
+		var channel = new Channel(server, id, name);
+		server.getChannelManager().addChannel(channel);
+		server.getClientManager().broadcast(server.getMetaData());
+		System.out.println("Added channel " + channel.getAsTag() + ".");
+	}
+
+	private void removeChannel(ConcordServer server, String[] args) throws IOException {
+		if (args.length != 1) {
+			System.err.println("Missing required channel name.");
+			return;
+		}
+		String name = args[0].trim().toLowerCase();
+		Optional<Channel> optionalChannel = server.getChannelManager().getChannelByName(name);
+		if (optionalChannel.isEmpty()) {
+			System.err.println("No channel with that name exists.");
+			return;
+		}
+		Channel channelToRemove = optionalChannel.get();
+		Channel alternative = null;
+		for (var c : server.getChannelManager().getChannels()) {
+			if (!c.equals(channelToRemove)) {
+				alternative = c;
+				break;
+			}
+		}
+		if (alternative == null) {
+			System.err.println("No alternative channel could be found. A server must always have at least one channel.");
+			return;
+		}
+		for (var client : channelToRemove.getConnectedClients()) {
+			server.getChannelManager().moveToChannel(client, alternative);
+		}
+		server.getChannelManager().removeChannel(channelToRemove);
+		server.getDb().getContext().dropCollection(channelToRemove.getMessageCollection().getName());
+		server.getConfig().getChannels().removeIf(channelConfig -> channelConfig.getName().equals(channelToRemove.getName()));
+		server.getConfig().save();
+		server.getClientManager().broadcast(server.getMetaData());
+		System.out.println("Removed the channel " + channelToRemove);
+	}
+
+	private void listChannels(ConcordServer server) {
+		StringBuilder sb = new StringBuilder();
+		server.getChannelManager().getChannels().stream().sorted()
+				.forEachOrdered(channel -> sb.append(channel.getAsTag())
+						.append(" - ").append(channel.getConnectedClients().size())
+						.append(" users").append("\n")
+				);
+		System.out.print(sb);
+	}
+}

server/src/main/java/nl/andrewl/concord_server/cli/command/RemoveChannelCommand.java

@@ -1,44 +0,0 @@
-package nl.andrewl.concord_server.cli.command;
-
-import nl.andrewl.concord_server.channel.Channel;
-import nl.andrewl.concord_server.ConcordServer;
-import nl.andrewl.concord_server.cli.ServerCliCommand;
-
-import java.util.Optional;
-
-public class RemoveChannelCommand implements ServerCliCommand {
-	@Override
-	public void handle(ConcordServer server, String[] args) throws Exception {
-		if (args.length != 1) {
-			System.err.println("Missing required channel name.");
-			return;
-		}
-		String name = args[0].trim().toLowerCase();
-		Optional<Channel> optionalChannel = server.getChannelManager().getChannelByName(name);
-		if (optionalChannel.isEmpty()) {
-			System.err.println("No channel with that name exists.");
-			return;
-		}
-		Channel channelToRemove = optionalChannel.get();
-		Channel alternative = null;
-		for (var c : server.getChannelManager().getChannels()) {
-			if (!c.equals(channelToRemove)) {
-				alternative = c;
-				break;
-			}
-		}
-		if (alternative == null) {
-			System.err.println("No alternative channel could be found. A server must always have at least one channel.");
-			return;
-		}
-		for (var client : channelToRemove.getConnectedClients()) {
-			server.getChannelManager().moveToChannel(client, alternative);
-		}
-		server.getChannelManager().removeChannel(channelToRemove);
-		server.getDb().getContext().dropCollection(channelToRemove.getMessageCollection().getName());
-		server.getConfig().getChannels().removeIf(channelConfig -> channelConfig.getName().equals(channelToRemove.getName()));
-		server.getConfig().save();
-		server.getClientManager().broadcast(server.getMetaData());
-		System.out.println("Removed the channel " + channelToRemove);
-	}
-}

server/src/main/java/nl/andrewl/concord_server/client/ClientManager.java

@@ -43,10 +43,15 @@ public class ClientManager {
 	 * the client. The server will register the client in its global set of
 	 * connected clients, and it will immediately move the client to the default
 	 * channel.
+	 * <p>
+	 *     If the client provides a session token with their identification
+	 *     message, then we should load their data from our database, otherwise
+	 *     we assume this is a new client.
+	 * </p>
 	 * @param identification The client's identification data.
 	 * @param clientThread The client manager thread.
 	 */
-	public void registerClient(Identification identification, ClientThread clientThread) {
+	public void handleLogIn(Identification identification, ClientThread clientThread) {
 		ClientConnectionData data;
 		try {
 			data = identification.getSessionToken() == null ? getNewClientData(identification) : getClientDataFromDb(identification);
@@ -78,7 +83,7 @@ public class ClientManager {
 	 * they're currently in.
 	 * @param clientId The id of the client to remove.
 	 */
-	public void deregisterClient(UUID clientId) {
+	public void handleLogOut(UUID clientId) {
 		var client = this.clients.remove(clientId);
 		if (client != null) {
 			client.getCurrentChannel().removeClient(client);

server/src/main/java/nl/andrewl/concord_server/client/ClientThread.java

@@ -112,7 +112,7 @@ public class ClientThread extends Thread {
 		}
 
 		if (this.clientId != null) {
-			this.server.getClientManager().deregisterClient(this.clientId);
+			this.server.getClientManager().handleLogOut(this.clientId);
 		}
 		try {
 			if (!this.socket.isClosed()) {
@@ -140,7 +140,7 @@ public class ClientThread extends Thread {
 			try {
 				var msg = this.server.getSerializer().readMessage(this.in);
 				if (msg instanceof Identification id) {
-					this.server.getClientManager().registerClient(id, this);
+					this.server.getClientManager().handleLogIn(id, this);
 					return true;
 				}
 			} catch (IOException e) {

server/src/main/java/nl/andrewl/concord_server/event/ChannelUsersRequestHandler.java

@@ -1,17 +0,0 @@
-package nl.andrewl.concord_server.event;
-
-import nl.andrewl.concord_core.msg.types.ChannelUsersRequest;
-import nl.andrewl.concord_core.msg.types.ChannelUsersResponse;
-import nl.andrewl.concord_server.client.ClientThread;
-import nl.andrewl.concord_server.ConcordServer;
-
-public class ChannelUsersRequestHandler implements MessageHandler<ChannelUsersRequest> {
-	@Override
-	public void handle(ChannelUsersRequest msg, ClientThread client, ConcordServer server) throws Exception {
-		var optionalChannel = server.getChannelManager().getChannelById(msg.getChannelId());
-		if (optionalChannel.isPresent()) {
-			var channel = optionalChannel.get();
-			client.sendToClient(new ChannelUsersResponse(channel.getUserData()));
-		}
-	}
-}

server/src/main/java/nl/andrewl/concord_server/event/EventListener.java

@@ -1,9 +0,0 @@
-package nl.andrewl.concord_server.event;
-
-import nl.andrewl.concord_core.msg.types.Chat;
-import nl.andrewl.concord_server.client.ClientThread;
-import nl.andrewl.concord_server.ConcordServer;
-
-public interface EventListener {
-	default void chatMessageReceived(ConcordServer server, Chat chat, ClientThread client) {}
-}

server/src/main/java/nl/andrewl/concord_server/event/MessageHandler.java

@@ -4,6 +4,11 @@ import nl.andrewl.concord_core.msg.Message;
 import nl.andrewl.concord_server.client.ClientThread;
 import nl.andrewl.concord_server.ConcordServer;
 
+/**
+ * Defines a component which can handle messages of a certain type which were
+ * received from a client.
+ * @param <T> The type of message to be handled.
+ */
 public interface MessageHandler<T extends Message> {
 	void handle(T msg, ClientThread client, ConcordServer server) throws Exception;
 }

server/src/main/java/nl/andrewl/concord_server/util/Pair.java

@@ -1,3 +0,0 @@
-package nl.andrewl.concord_server.util;
-
-public record Pair<A, B>(A first, B second) {}