TCPChannelFactory.java

/* Copyright (c) 2006-2009 Jan S. Rellermeyer
 * Systems Group,
 * Department of Computer Science, ETH Zurich.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    - Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    - Neither the name of ETH Zurich nor the names of its contributors may be
 *      used to endorse or promote products derived from this software without
 *      specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package ch.ethz.iks.r_osgi.impl;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.net.BindException;
import java.net.ServerSocket;
import java.net.Socket;

import org.osgi.service.log.LogService;

import ch.ethz.iks.r_osgi.Remoting;
import ch.ethz.iks.r_osgi.URI;
import ch.ethz.iks.r_osgi.channels.ChannelEndpoint;
import ch.ethz.iks.r_osgi.channels.NetworkChannel;
import ch.ethz.iks.r_osgi.channels.NetworkChannelFactory;
import ch.ethz.iks.r_osgi.messages.RemoteOSGiMessage;
import ch.ethz.iks.util.SmartObjectInputStream;
import ch.ethz.iks.util.SmartObjectOutputStream;

/**
 * channel factory for (persistent) TCP transport. This is the default protocol.
 * 
 * @author Jan S. Rellermeyer, ETH Zurich
 * @since 0.6
 */
final class TCPChannelFactory implements NetworkChannelFactory {

	static final String PROTOCOL = "r-osgi"; //$NON-NLS-1$
	Remoting remoting;
	private TCPAcceptorThread thread;
	protected int listeningPort;

	/**
	 * get a new connection.
	 * 
	 * @param endpoint
	 *            the channel endpoint.
	 * @param endpointURI
	 *            the URI of the remote host.
	 * @return the transport channel.
	 * @throws IOException 
	 */
	public NetworkChannel getConnection(final ChannelEndpoint endpoint,
			final URI endpointURI) throws IOException {
		return new TCPChannel(endpoint, endpointURI);
	}

	/**
	 * Activate the factory. Is called by R-OSGi when the factory is discovered.
	 * 
	 * @see ch.ethz.iks.r_osgi.channels.NetworkChannelFactory#activate(ch.ethz.iks.r_osgi.Remoting)
	 */
	public void activate(final Remoting r) throws IOException {
		remoting = r;
		thread = new TCPAcceptorThread();
		thread.start();
	}

	/**
	 * Deactivate the factory.
	 * 
	 * @see ch.ethz.iks.r_osgi.channels.NetworkChannelFactory#deactivate(ch.ethz.iks.r_osgi.Remoting)
	 */
	public void deactivate(final Remoting r) throws IOException {
		if(thread != null) {
			thread.interrupt();
		}
		remoting = null;
	}

	/**
	 * get the listening port.
	 * 
	 * @see ch.ethz.iks.r_osgi.channels.NetworkChannelFactory#getListeningPort(java.lang.String)
	 */
	public int getListeningPort(final String protocol) {
		return listeningPort;
	}

	/**
	 * the inner class representing a channel with TCP transport. The TCP
	 * connection uses the TCP keepAlive option to reduce reconnection overhead.
	 * 
	 * @author Jan S. Rellermeyer, ETH Zurich
	 */
	private static final class TCPChannel implements NetworkChannel {
		/**
		 * the socket.
		 */
		Socket socket;

		/**
		 * the remote endpoint address.
		 */
		private final URI remoteEndpointAddress;

		/**
		 * the local endpoint address.
		 */
		private URI localEndpointAddress;

		/**
		 * the input stream.
		 */
		protected ObjectInputStream input;

		/**
		 * the output stream.
		 */
		protected ObjectOutputStream output;

		/**
		 * the channel endpoint.
		 */
		ChannelEndpoint endpoint;

		/**
		 * connected ?
		 */
		boolean connected = true;

		/**
		 * create a new TCPChannel.
		 * 
		 * @param endpoint
		 *            the channel endpoint.
		 * @param endpointAddress
		 *            the remote peer's URI.
		 * @throws IOException
		 *             in case of IO errors.
		 */
		TCPChannel(final ChannelEndpoint endpoint, final URI endpointAddress)
				throws IOException {
			int port = endpointAddress.getPort();
			if (port == -1) {
				port = 9278;
			}
			this.endpoint = endpoint;
			remoteEndpointAddress = endpointAddress;
			open(new Socket(endpointAddress.getHost(), port));
			new ReceiverThread().start();
		}

		/**
		 * create a new TCPChannel from an existing socket.
		 * 
		 * @param socket
		 *            the socket.
		 * @throws IOException
		 *             in case of IO errors.
		 */
		public TCPChannel(final Socket socket) throws IOException {
			remoteEndpointAddress = URI.create(getProtocol() + "://" //$NON-NLS-1$
					+ socket.getInetAddress().getHostName() + ":" //$NON-NLS-1$
					+ socket.getPort());
			open(socket);
		}

		/**
		 * bind the channel to a channel endpoint.
		 * 
		 * @param e
		 *            the channel endpoint.
		 * 
		 * @see ch.ethz.iks.r_osgi.channels.NetworkChannel#bind(ch.ethz.iks.r_osgi.channels.ChannelEndpoint)
		 */
		public void bind(final ChannelEndpoint e) {
			endpoint = e;
			new ReceiverThread().start();
		}

		/**
		 * open the channel.
		 * 
		 * @param socket
		 *            the socket.
		 * @throws IOException
		 *             if something goes wrong.
		 */
		private void open(final Socket s) throws IOException {
			socket = s;
			localEndpointAddress = URI.create(getProtocol() + "://" //$NON-NLS-1$
					+ socket.getLocalAddress().getHostName() + ":" //$NON-NLS-1$
					+ socket.getLocalPort());
			try {
				socket.setKeepAlive(true);
			} catch (final Throwable t) {
				// for 1.2 VMs that do not support the setKeepAlive
			}
			socket.setTcpNoDelay(true);
			output = new SmartObjectOutputStream(new BufferedOutputStream(
					socket.getOutputStream()));
			output.flush();
			input = new SmartObjectInputStream(new BufferedInputStream(socket
					.getInputStream()));
		}

		/**
		 * get the String representation of the channel.
		 * 
		 * @return the ID. *
		 * @see java.lang.Object#toString()
		 */
		public String toString() {
			return "TCPChannel (" + getRemoteAddress() + ")"; //$NON-NLS-1$ //$NON-NLS-2$
		}

		/**
		 * close the channel.
		 * @throws IOException 
		 */
		public void close() throws IOException {
			socket.close();
			// receiver.interrupt();
			connected = false;
		}

		/**
		 * get the protocol that is implemented by the channel.
		 * 
		 * @return the protocol.
		 * @see ch.ethz.iks.r_osgi.channels.NetworkChannel#getProtocol()
		 */
		public String getProtocol() {
			return PROTOCOL;
		}

		/**
		 * get the remote address.
		 * 
		 * @see ch.ethz.iks.r_osgi.channels.NetworkChannel#getRemoteAddress()
		 */
		public URI getRemoteAddress() {
			return remoteEndpointAddress;
		}

		/**
		 * get the local address.
		 * 
		 * @see ch.ethz.iks.r_osgi.channels.NetworkChannel#getLocalAddress()
		 */
		public URI getLocalAddress() {
			return localEndpointAddress;
		}

		/**
		 * send a message through the channel.
		 * 
		 * @param message
		 *            the message.
		 * @throws IOException
		 *             in case of IO errors.
		 */
		public void sendMessage(final RemoteOSGiMessage message)
				throws IOException {
			if (RemoteOSGiServiceImpl.MSG_DEBUG) {
				RemoteOSGiServiceImpl.log.log(LogService.LOG_DEBUG,
						"{TCP Channel} sending " + message); //$NON-NLS-1$
			}
			message.send(output);
		}

		/**
		 * the receiver thread continuously tries to receive messages from the
		 * other endpoint.
		 * 
		 * @author Jan S. Rellermeyer, ETH Zurich
		 * @since 0.6
		 */
		class ReceiverThread extends Thread {
			ReceiverThread() {
				setName("TCPChannel:ReceiverThread:" + getRemoteAddress()); //$NON-NLS-1$
				setDaemon(true);
			}

			public void run() {
				while (connected) {
					try {
						final RemoteOSGiMessage msg = RemoteOSGiMessage
								.parse(input);
						if (RemoteOSGiServiceImpl.MSG_DEBUG) {
							RemoteOSGiServiceImpl.log.log(LogService.LOG_DEBUG,
									"{TCP Channel} received " + msg); //$NON-NLS-1$
						}
						endpoint.receivedMessage(msg);
					} catch (final IOException ioe) {
						connected = false;
						try {
							socket.close();
						} catch (final IOException e1) {
						}
						endpoint.receivedMessage(null);
						return;
					} catch (final Throwable t) {
						t.printStackTrace();
					}
				}
			}
		}
	}

	/**
	 * TCPThread, handles incoming tcp messages.
	 */
	protected final class TCPAcceptorThread extends Thread {
		/**
		 * the socket.
		 */
		private ServerSocket socket;

		/**
		 * creates and starts a new TCPThread.
		 * 
		 * @throws IOException
		 *             if the server socket cannot be opened.
		 */
		TCPAcceptorThread() throws IOException {
			setName("TCPChannel:TCPAcceptorThread"); //$NON-NLS-1$
			setDaemon(true);

			int e = 0;
			while (true) {
				try {
					listeningPort = RemoteOSGiServiceImpl.R_OSGI_PORT + e;
					socket = new ServerSocket(listeningPort);

					if (e != 0) {
						System.err
								.println("WARNING: Port " //$NON-NLS-1$
										+ RemoteOSGiServiceImpl.R_OSGI_PORT
										+ " already in use. This instance of R-OSGi is running on port " //$NON-NLS-1$
										+ listeningPort);
					}
					RemoteOSGiServiceImpl.R_OSGI_PORT = listeningPort;
					return;
				} catch (final BindException b) {
					e++;
				}
			}
		}

		/**
		 * thread loop.
		 * 
		 * @see java.lang.Thread#run()
		 */
		public void run() {
			while (!isInterrupted()) {
				try {
					// accept incoming connections and build channel endpoints
					// for them
					remoting.createEndpoint(new TCPChannel(socket.accept()));
				} catch (final IOException ioe) {
					ioe.printStackTrace();
				}
			}
		}
	}

}