serversocketlistener.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.socket.tcp;



import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetSocketAddress;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

import org.butor.log.Log;

/**
 * This object handle server socket listening
 * and welcoming. This object is runnable. it run in a thread
 * and listen for incoming client sockets and then relay
 * theses clients to another object for handling. that object implements
 * the interface IClientSocketHandler that this class use to comunicate with it.
 * 
 * @author Aiman Sawan
 */
public class ServerSocketListener implements Runnable {
	// handle the port number to listen to.
	protected int f_tcpPort;
	protected ServerSocketChannel f_serverSocket;
	// object that will handle incoming client sockets
	protected ISocketConnectionHandler f_socketConnectionHandler;
	protected Thread f_serverSocketThread = null;
	protected boolean f_shutdown;

	/**
	 * Constructor.
	 * 
	 * @param tcpPort int, the port number to listen to.
	 * @param handler ISocketConnectionHandler, object that will 
	 * 		handle incoming socket connections
	 */
	public ServerSocketListener(int tcpPort, ISocketConnectionHandler handler)
		throws IOException {

		if (handler == null) {
			throw new IOException("Got null ISocketConnectionHandler!");
		}

		f_tcpPort = tcpPort;
		f_socketConnectionHandler = handler;
		f_shutdown = false;

		// Create a server socket to accept connections
		f_serverSocket = ServerSocketChannel.open();
		f_serverSocket.socket().bind(new InetSocketAddress(f_tcpPort));

		start();
	}
	/**
	 * get shutdown status.
	 * 
	 * @return boolean, shutdwon flag.
	 */
	public boolean isShutdown() {
		return f_shutdown;
	}
	/**
	 * run the thread
	 */
	public void run() {

		Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Start...");

		while (!f_shutdown) {

			// As connection comes in, give them to the org.butor.web.listener.
			try {
				if (f_socketConnectionHandler == null) {
					Log.logStr(
						Log.LOG_LEVEL_LOW,
						this,
						Log.LOG_TYPE_INFO,
						"run()",
						"Got null ISocketConnectionHandler! Shutting down.");
					shutdown();
				}

				// set receive timeout to be able to shutdown.
				// if the jvm does not close the socket when the close() are invoked.
				Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Listening for client connections ...");
				
				SocketChannel socket = f_serverSocket.accept();
				if (socket != null) {
					Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Got client connection. " +socket);
					SocketConnection conn = new SocketConnection();
					conn.setSocket(socket);
					Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Passing socket to handler. Handler=[" +f_socketConnectionHandler.getClass().getName() +"]");
					
					f_socketConnectionHandler.handleSocketConnection(conn);

				} else {
					Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Got NULL client connections!");
				}

			} catch (InterruptedIOException e) {
				// OK for time out
				if (f_shutdown) {
					break;
				}
				
			} catch (IOException e) {
				Log.logStr(
					Log.LOG_LEVEL_LOW,
					this,
					Log.LOG_TYPE_INFO,
					"run()",
					e.getMessage());
			}
		}

		Log.logStr(this, Log.LOG_TYPE_INFO, "run()", "Stopped.");
	}
	/**
	 * Shutdown this object
	 */
	public void shutdown() {
		f_shutdown = true;

		if (f_serverSocket != null) {
			// When the thread is killed, close the server socket
			try {
				f_serverSocket.close();
				
			} catch (IOException e) {
				Log.logException(this, Log.LOG_TYPE_ERROR, "shutdown()", e);
			}
		}
	}
	/**
	 * run this thread.
	 * keep a reference on this thread to interrupt it when
	 * shutting down.
	 */
	protected void start() {
		if (f_shutdown) {
			return;
		}

		Log.logStr(this, Log.LOG_TYPE_INFO, "start()", "will listen for tcp connections on port [" +f_tcpPort +"].");

		f_serverSocketThread =
			new Thread(this, "Server_Socket_Listener_on_port_" + f_tcpPort);
		f_serverSocketThread.start();
	}
}