tcpconnectionmanager.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

/*
 *
 * $Id: TcpConnectionManager.java,v 1.8 2002/06/11 19:26:39 hamada Exp $
 *
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA"
 *    must not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 SUN MICROSYSTEMS OR
 * ITS 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.
 *
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 */


package net.jxta.impl.endpoint.tcp;

import java.net.*;
import java.io.*;
import java.util.*;

import org.apache.log4j.Category;
import org.apache.log4j.Priority;

import net.jxta.document.MimeMediaType;
import net.jxta.endpoint.*;

import net.jxta.impl.endpoint.MessageImpl;
import net.jxta.impl.endpoint.MessageWireFormat;
import net.jxta.impl.endpoint.MessageWireFormatFactory;


/**
 * Low-level TcpMessenger
 *
 * @since       JXTA 1.0
 */

public class TcpConnectionManager {

	private static final Category LOG = Category.getInstance(TcpConnectionManager.class.getName());
	private static final long TcpConnectionGCDelay = 60 * 60 * 1000; // 1 Hour
	private Timer  tcpConnectionGCTimer = new Timer();
	private TcpTransport proto = null;
	private Hashtable    openConnections    = new Hashtable();

	public TcpConnectionManager (TcpTransport p) {

		proto = p;
		// Start the TcpConnection garbage collector timer
		tcpConnectionGCTimer.scheduleAtFixedRate (new TcpConnectionGCTask (this),
		        TcpConnectionGCDelay,
		        TcpConnectionGCDelay);
	}

	private synchronized void registerTcpConnection (EndpointAddress addr, TcpConnection conn) {

		if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("Register connection to " + addr.toString());

		TcpConnection old = (TcpConnection) openConnections.put (addr.toString(), conn);
		if (old != null) {
			old.close();
		}
	}

	private synchronized void unregisterTcpConnection (EndpointAddress addr) {

		TcpConnection old = (TcpConnection) openConnections.remove (addr.toString());
		if (old != null) {
			old.close();
		}
	}

	/**
	 * Get or create a connection for a given destination.
	 **/
	public synchronized TcpConnection getTcpConnection (EndpointAddress destAddr) {

		EndpointAddress addr = (EndpointAddress) destAddr.clone();
		addr.setServiceName (null);
		addr.setServiceParameter (null);

		TcpConnection conn = null;
		// If there is already a connection, use it.
		if (LOG.isEnabledFor(Priority.DEBUG))
			LOG.debug("Looking for connection to " + addr.toString());
		conn = (TcpConnection) openConnections.get (addr.toString());

		if (conn == null) {
			// No existing connection. Create one.
			try {
				if (LOG.isEnabledFor(Priority.DEBUG))
					LOG.debug("Creating new connection to " + addr.toString());
				conn = new TcpConnection (addr, proto);
				// Register it.
				registerTcpConnection (addr, conn);
			} catch (Exception e) {
			    
		            if (LOG.isEnabledFor(Priority.DEBUG))
					LOG.debug("Creating new connection to " 
					+ addr.toString() +
					"failed ", e);
			     return null;
			}
		} else {
			if (LOG.isEnabledFor(Priority.DEBUG))
				LOG.debug("Reusing existing connection to " + addr.toString());
		}

		conn.setLastUsed (System.currentTimeMillis());
		return conn;
	}

	/**
	 * Remove TcpConnection that have not been used for more than TcpConnectionGCDelay.
	 **/

	protected void tcpConnectionGC () {

		if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("TcpConnectionGC starts");

		Enumeration enum = openConnections.keys();
		if ((enum == null) || (!enum.hasMoreElements())) {
			// There is currentely no TcpConnection. Nothing to do.
			if (LOG.isEnabledFor(Priority.DEBUG)) 
			    LOG.debug("TcpConnectionGC: no connection. Nothing to do.");
			return;
		}

		TcpConnection conn = null;
		long      lastUsed = 0;
		long   currentTime = 0;
		String    destAddr = null;

		while (enum.hasMoreElements()) {
			try {
				destAddr = (String) enum.nextElement();
				conn = (TcpConnection) openConnections.get (destAddr);
				synchronized (this) {
					if (conn == null) {
						// Since this method is not synchronized, the connection may have been removed
						// since the begining of the execution of the loop.
						continue;
					}
					lastUsed = conn.getLastUsed();
					currentTime = System.currentTimeMillis();

					if ((currentTime - lastUsed) >= TcpConnectionGCDelay) {
						// This connection has not been used for a while. Delete it.
						conn.close();
						openConnections.remove (destAddr);
						if (LOG.isEnabledFor(Priority.DEBUG))
						    LOG.debug("TcpConnectionGC removes unused connection fon to " + destAddr);
						continue;
					}
				}

			} catch (Exception ez1) {
				continue;
			}
		}
		if (LOG.isEnabledFor(Priority.DEBUG)) 
		    LOG.debug("TcpConnectionGC completed.");
	}



	/**
	 * The TcpConnection garbage collector class.
	 **/

	public class TcpConnectionGCTask extends TimerTask {

		TcpConnectionManager manager = null;

		/**
		 *Constructor for the GC Task object
		 *
		 */
		public TcpConnectionGCTask(TcpConnectionManager manager) {
			this.manager = manager;
		}

		/**
		 *Description of the Method
		 *
		 * @param  timer  Description of Parameter
		 */
		public void run() {
			// Run the TcpConnectionManager GC.
			manager.tcpConnectionGC();
		}
	}
}