tcpconnection.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: TcpConnection.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.EndpointReceiveQueue;
import net.jxta.impl.endpoint.MessageWireFormat;
import net.jxta.impl.endpoint.MessageWireFormatFactory;


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

public class TcpConnection implements Runnable {
    private static final Category LOG = Category.getInstance(TcpConnection.class.getName());
    public static final int MaxNbOfMessages = 40;

    private InetAddress inetAddress = null;
    private int port = 0;
    private TcpTransport proto = null;
    private Header header = null;
    private TcpSocket tcpSocket = null;
    private boolean waiting = false;
    private EndpointAddress dstAddress = null;
    private long lastUsed = 0;
    private String dstAddrString = null;
    private Thread thread = null;
    private EndpointReceiveQueue queue = null;
    private long nbOfMessagesSent = 0;

    public TcpConnection (EndpointAddress destaddr,
			  TcpTransport p)
        throws IOException {

        // Not much has to be done: the connection with the remote node
        // will happen only when the data will be sent.
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("Constructor");
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("   addr = " + destaddr.toString());

        header = new Header();
        proto = p;

        this.dstAddress = (EndpointAddress) destaddr.clone();
        try {
            String tmp = destaddr.getProtocolAddress();
            int portIndex = tmp.indexOf(":");
            if (portIndex == -1) {
                throw new IOException();
            }
            port = Integer.valueOf(tmp.substring(portIndex + 1)).intValue();
            inetAddress = InetAddress.getByName(tmp.substring(0, portIndex));
	    dstAddrString = inetAddress.getHostAddress();
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("Constructor using: " + inetAddress.getHostAddress());
        } catch (Exception e) {
            if (LOG.isEnabledFor(Priority.INFO)) LOG.info("Bad address " + destaddr.toString(), e);
            throw new IOException("Bad address " + destaddr.toString());
        }
	
	tcpSocket = new TcpSocket (inetAddress, port);
    }


    // Try to connect. This operation is idempotent.
    private void connect () {

	synchronized (this) {
	    if (queue == null) {
		// There is new queue. Create one.
		queue = new EndpointReceiveQueue();
		queue.setMaxNbOfMessages (MaxNbOfMessages);
	    }

	    // Start the background thread.
	    if (thread != null) {
		// Nothing to do
		return;
	    }
	    thread = new Thread (this, "TCP Connection to " + dstAddrString + " [Unused]");
	    thread.start();
	}
	Thread.yield();
    }

    private synchronized void setThreadName () {

	if (thread != null) {
	    try {
		thread.setName ("TCP Connection to " + dstAddrString + " [" +
				queue.getNbOfQueuedMessages() + ", " +
				nbOfMessagesSent + ", " +
				(isConnected() ? "Connected" : "Disconnected") + 
				" ]");
	    } catch (Exception ez1) {
		if (LOG.isEnabledFor(Priority.ERROR)) LOG.error("Cannot change thread name", ez1);
	    }
	}
    }


    // Public method that sends messages to the remote peer.
    // Only queue the message and let the background thread actually sends the message.

    public void sendMessage (Message msg) throws IOException {

	// Try to get a Socket just to check that a connection is possible.
	if ( tcpSocket.getSocket (5000) == null) {
	    if (LOG.isEnabledFor(Priority.DEBUG)) {
		LOG.debug("sendMessage() cannot get a socket for " + dstAddrString);
	    }
	    throw new IOException();
	}

	connect();
	// Queue the message.
	synchronized (this) {
	    queue.push (msg);
	    setThreadName();
	}
	Thread.yield();
    }


    // This is the background Thread. While the connection is active, takes
    // messages from the queue and send it.
    public void run() {
	
	Message msg = null;
	while (true) {

	    try {
		// Wait for messages to be sent.
		msg = queue.waitForMessage();
		if (msg == null) {
		    // If the message is null, the queue has been closed.
		    thread = null;
		    return;
		}
		setThreadName();
		// Send the message.
		doSendMessage (msg);

	    } catch (InterruptedException ez1) {
		// The connection is just being close. This Thread must exit.
		thread = null;
		return;
	    } catch (IOException ez2) {
		// The message failed. Notify the failure
		notifyFailure();
		thread = null;
		return;
	    }
	}
    }

    /**
     * Send a TransportMessage onto that link.
     *
     * @param message TransportMessage to be sent.
     */
    private void doSendMessage(Message message) throws IOException {

        if (dstAddress == null) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendMessage: no destination address");
            throw new IOException();
        }
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendMessage");
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("     to = " + dstAddress.toString());

        // Build the protocol header
        // Allocate a buffer to contain the message and the header

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        MessageWireFormatFactory.newMessageWireFormat( 
            new MimeMediaType( "application/x-jxta-msg" ) )
            .writeMessage(baos, message);
        baos.close();
        byte bytes[] = baos.toByteArray();
        ByteArrayInputStream inputStream = new ByteArrayInputStream(bytes);

        Vector msgBuffers = new Vector();

        msgBuffers.addElement( new byte[header.length] );

        int msgSize = 0;
        int bufferSize = 4096;
	boolean success = false;

        while( true ) {
            byte [] nextBuffer = new byte[bufferSize];

            int readLength = inputStream.read( nextBuffer );

            if( -1 == readLength )
                break;

            if( 0 == readLength )
                continue;

            if( readLength < bufferSize ) {
                byte [] anotherBuffer = new byte[readLength];
                System.arraycopy( nextBuffer, 0, anotherBuffer, 0, readLength );
                nextBuffer = anotherBuffer;
            }

            msgSize += nextBuffer.length;
            msgBuffers.addElement( nextBuffer );
        }

	
	// First build the header
	header.cmd = Header.UNICAST;

	header.srcAddr = proto.usingInterface.getAddress();
	header.srcPort = proto.serverSocketPort;
	header.option = Header.NONBLOCKING;
	header.size = msgSize;

	header.buildForNetwork( (byte []) msgBuffers.elementAt(0), 0);

	int retryAttempt = 0;

	while ( retryAttempt < 2) {

	    // Open a socket with the destination and send the message
	    Socket socket = tcpSocket.getSocket (5000);
	    if (socket == null) {
		if (LOG.isEnabledFor(Priority.DEBUG)) {
		    LOG.debug("sendMessage() cannot get a socket for " + dstAddress.toString());
		}
		throw new IOException();
	    }
	    try {
		OutputStream outputStream = socket.getOutputStream();
		InputStream ip = socket.getInputStream();

		if (retryAttempt == 0) {
		    // Drain the back channel, just in case some keep alive
		    // hint is hanging there. Use the last one we find.
		    // Normaly the hint arrives too late for use at the end
		    // of transmission and we do not want to wait for it. The hint
		    // never arrives before we send something. As a result, we
		    // can always assume that we get that hint at the begining of
		    // the next transaction. If it tells us that the connection
		    // should be closed, we can assume that the other side has
		    // closed already and that we must re-open.
		    int rep = 1;
		    for (int i = ip.available(); i--> 0;) rep = ip.read();
		    if (rep == 0) {
			// close and re-open.
			if (LOG.isEnabledFor(Priority.DEBUG)) {
			    LOG.debug("Other party wanted the connection closed.");
			}
			try {
			    outputStream.close();
			} catch (Exception canthelp) {
			}
			
			outputStream.close();
			ip.close();

			tcpSocket.close();
			socket = tcpSocket.getSocket(5000);
			if (socket == null) {
			    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendMessage cannot get socket for " + dstAddress.toString());
			    throw new IOException();
			} 
			outputStream = socket.getOutputStream();
			ip = socket.getInputStream();
		    }
		}

		for( int eachBuffer = 0; eachBuffer < msgBuffers.size();eachBuffer++ ) {
		    // Send the message
		    outputStream.write( (byte[]) msgBuffers.elementAt(eachBuffer) );
		}

		outputStream.flush();
		setLastUsed (System.currentTimeMillis());
		success = true;
		break;

	    } catch (Exception e) {

		// The connection has failed. Try to reconnect once
		// before failing.
		++retryAttempt;
		tcpSocket.close();
		if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendMessage current socket is closed.");
		continue;
	    }
	}

	if (success) {
	    // we force a resheduling here, allowing other threads to run
	    ++nbOfMessagesSent;
	    Thread.yield();
	} else {
	    tcpSocket.setLastFailed (System.currentTimeMillis());
	    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendMessage failed - exit");
	    throw new IOException ();
	}
    }

    public void notifyActivity() {
	tcpSocket.notifyActivity();
    }

    private synchronized void notifyFailure() {
	close();
    }

    public synchronized void close() {

	tcpSocket.close();

	if (queue != null) {
	    queue.close();
	    queue = null;
	}
	if (thread != null) {
	    try {
		thread.interrupt();
		thread = null;
	    } catch (Exception ez1) {
		if (LOG.isEnabledFor(Priority.WARN)) LOG.warn("Cannot interrupt thread for " + dstAddrString, ez1);
	    }
	}
    }

    public synchronized  boolean isConnected() {
	Socket socket = tcpSocket.getSocket(1000);
	return socket != null;
    }

    public synchronized long getLastUsed () {
	return lastUsed;
    }

    public synchronized void setLastUsed (long time) {
	lastUsed = time;
    }

    // Just in case the code that allocated an instance of this object forgot to do "close".
    public void finalize() {
	close();
    }
}