Moved client to net package, removed unnecessary recipient property

src/main/java/envoy/client/net/Client.java

@@ -0,0 +1,186 @@
+package envoy.client.net;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.net.Socket;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.logging.Logger;
+
+import javax.naming.TimeLimitExceededException;
+
+import envoy.client.Config;
+import envoy.client.database.LocalDb;
+import envoy.client.util.EnvoyLog;
+import envoy.data.*;
+import envoy.event.IdGeneratorRequest;
+import envoy.util.SerializationUtils;
+
+/**
+ * Establishes a connection to the server, performs a handshake and delivers
+ * certain objects to the server.<br>
+ * <br>
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>Client.java</strong><br>
+ * Created: <strong>28 Sep 2019</strong><br>
+ *
+ * @author Kai S. K. Engelbart
+ * @author Maximilian K&auml;fer
+ * @author Leon Hofmeister
+ * @since Envoy v0.1-alpha
+ */
+public class Client implements Closeable {
+
+	// Connection handling
+	private Socket		socket;
+	private Receiver	receiver;
+	private boolean		online;
+
+	// Asynchronously initialized during handshake
+	private volatile User		sender;
+	private volatile Contacts	contacts;
+
+	// Configuration and logging
+	private static final Config	config	= Config.getInstance();
+	private static final Logger logger = EnvoyLog.getLogger(Client.class.getSimpleName());
+
+	/**
+	 * Enters the online mode by acquiring a user ID from the server. As a
+	 * connection has to be established and a handshake has to be made, this method
+	 * will block for up to 5 seconds. If the handshake does exceed this time limit,
+	 * an exception is thrown.
+	 *
+	 * @param credentials the login credentials of the user
+	 * @param localDb     the local database used to persist the current
+	 *                    {@link IdGenerator}
+	 * @return a message cache containing all unread messages from the server that
+	 *         can be relayed after initialization
+	 * @throws Exception if the online mode could not be entered or the request
+	 *                   failed for some other reason
+	 * @since Envoy v0.2-alpha
+	 */
+	public MessageCache onlineInit(LoginCredentials credentials, LocalDb localDb) throws Exception {
+		// Establish TCP connection
+		logger.info(String.format("Attempting connection to server %s:%d...", config.getServer(), config.getPort()));
+		socket = new Socket(config.getServer(), config.getPort());
+		logger.info("Successfully connected to server.");
+
+		// Create message receiver
+		receiver = new Receiver(socket.getInputStream());
+
+		// Create cache for unread messages
+		final MessageCache cache = new MessageCache();
+
+		// Register user creation processor, contact list processor and message cache
+		receiver.registerProcessor(User.class, sender -> { logger.info("Acquired user object " + sender); this.sender = sender; });
+		receiver.registerProcessor(Contacts.class, contacts -> { logger.info("Acquired contacts object " + contacts); this.contacts = contacts; });
+		receiver.registerProcessor(Message.class, cache);
+
+		// Start receiver
+		new Thread(receiver).start();
+
+		// Write login credentials
+		logger.finest("Sending login credentials...");
+		SerializationUtils.writeBytesWithLength(credentials, socket.getOutputStream());
+
+		// Wait for a maximum of five seconds to acquire the sender object
+		long start = System.currentTimeMillis();
+		while (sender == null || contacts == null) {
+			if (System.currentTimeMillis() - start > 5000) throw new TimeLimitExceededException("Did not log in after 5 seconds");
+			Thread.sleep(500);
+		}
+
+		logger.info("Handshake completed.");
+		online = true;
+
+		// Remove user creation processor
+		receiver.removeAllProcessors();
+
+		// Register processors for message and status handling
+		final ReceivedMessageProcessor receivedMessageProcessor = new ReceivedMessageProcessor();
+		receiver.registerProcessor(Message.class, receivedMessageProcessor);
+
+		// Relay cached unread messages
+		cache.setProcessor(receivedMessageProcessor);
+
+		// TODO: Status handling
+
+		// Process message ID generation
+		receiver.registerProcessor(IdGenerator.class, localDb::setIdGenerator);
+
+		// Request a generator if none is present
+		if (!localDb.hasIdGenerator() || !localDb.getIdGenerator().hasNext()) requestIdGenerator();
+
+		return cache;
+	}
+
+	/**
+	 * Sends a message to the server.
+	 *
+	 * @param message the message to send
+	 * @throws IOException if the message does not reach the server
+	 * @since Envoy v0.3-alpha
+	 */
+	public void sendMessage(Message message) throws IOException {
+		writeObject(message);
+		message.nextStatus();
+	}
+
+	/**
+	 * Requests a new {@link IdGenerator} from the server.
+	 *
+	 * @throws IOException if the request does not reach the server
+	 * @since Envoy v0.3-alpha
+	 */
+	public void requestIdGenerator() throws IOException {
+		logger.info("Requesting new id generator...");
+		writeObject(new IdGeneratorRequest());
+	}
+
+	/**
+	 * @return a {@code Map<String, User>} of all users on the server with their
+	 *         user names as keys
+	 * @since Envoy v0.2-alpha
+	 */
+	public Map<String, User> getUsers() {
+		checkOnline();
+		Map<String, User> users = new HashMap<>();
+		contacts.getContacts().forEach(u -> users.put(u.getName(), u));
+		return users;
+	}
+
+	@Override
+	public void close() throws IOException { if (online) socket.close(); }
+
+	private void writeObject(Object obj) throws IOException {
+		checkOnline();
+		SerializationUtils.writeBytesWithLength(obj, socket.getOutputStream());
+	}
+
+	private void checkOnline() { if (!online) throw new IllegalStateException("Client is not online"); }
+
+	/**
+	 * @return the sender object that represents this client.
+	 * @since Envoy v0.1-alpha
+	 */
+	public User getSender() { return sender; }
+
+	/**
+	 * Sets the client user which is used to send messages.
+	 *
+	 * @param sender the client user to set
+	 * @since Envoy v0.2-alpha
+	 */
+	public void setSender(User sender) { this.sender = sender; }
+
+	/**
+	 * @return the {@link Receiver} used by this {@link Client}
+	 */
+	public Receiver getReceiver() { return receiver; }
+
+	/**
+	 * @return {@code true} if a connection to the server could be established
+	 * @since Envoy v0.2-alpha
+	 */
+	public boolean isOnline() { return online; }
+}