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 1.2 2002/03/04 21:42:57 echtcherbina 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 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) {
		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();
        }
    }
}