loopbackmessenger.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: LoopbackMessenger.java,v 1.8 2002/05/04 16:54:54 ddoolin 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
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 * 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;
import net.jxta.endpoint.*;

import java.io.*;

/**
 * This class implements local delivery of message (when the InputPipe and the
 * OutputPipe are located on the same peer)
 *
 * The reason this class is useful is that t may not always 
 * be possible to connect to oneself without actually
 * going to a relay.
 * If your peer is an http client, it is not able to connect to self
 * through the normal http transport.
 * 
 * Since transports cannot be relied on to perform a loopback, some layer
 * above has to figure out that a message is looping back.
 * Since peerid loopback does not explicitly asks to go through a real
 * transport, and since peerid addressing is the job of the router, it is
 * the router that performs loopback.
 *
 * The router could probably perform the lookback by delivering the message
 * to its own input queue, that would take a special transport instead of a
 * special messenger, which is the same kind of deal but would imply some
 * incoming message processing by the router for every message. In
 * contrast, the loopback messenger is setup once and the router will never
 * sees the messages. That's a good optimization.
 *
 * Alternatively, the endpoint service itself could figure out the
 * loopback, but since the API wants to give a messenger to the requestor
 * rather than just sending a message, the endpoint would have to setup a
 * loopback messenger anyway. So it is pretty much the same.
 *
 * Anyone with a better way, speak up.
 *
 * J-C
 */

public class LoopbackMessenger implements EndpointMessenger {

    private EndpointService endpoint = null;
    private EndpointAddress fullDest = null;
    private EndpointAddress apparentSrc = null;

    public LoopbackMessenger (EndpointService ep,
                              EndpointAddress src,
                              EndpointAddress dest) {
        endpoint = ep;
        fullDest = dest;
        apparentSrc = src;
    }

    public void sendMessage (Message message) throws IOException {

        message.setSourceAddress(apparentSrc);
        message.setDestinationAddress(fullDest);

        endpoint.demux(message);
    }

    public void close() {
    }
}