send.java

有关java 的p2p应用,是一般很好的教程,有兴趣的朋友应该好好阅读一下

/*
 * 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.
 *
 * $Id: send.java,v 1.9 2003/11/24 21:29:23 tra Exp $
 */


package net.jxta.impl.shell.bin.send;

import net.jxta.impl.shell.*;

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

import net.jxta.peergroup.*;
import net.jxta.endpoint.*;
import net.jxta.pipe.*;

/**
 * @version $Revision: 1.9 $
 * @since JXTA 1.0
 */

public class send extends ShellApp {
  ShellEnv env;

  public send() {
  }

  public void stopApp () {
  }

  public int startApp (String[] args) {
    if ((args == null) || (args.length != 2)) {
      println ("error: send <OutputPipe> <PipeMessage>");
      return ShellApp.appParamError;
    }

    env = getEnv();

    /*
     * extract the pipe info
     */

    String pipe = args[0];

    ShellObject obj = env.get (pipe);
    if (obj == null) {
      println ("send: cannot access " + pipe);
      return ShellApp.appMiscError;
    }

    OutputPipe op = null;
    try {
      op = (OutputPipe) obj.getObject();
    } catch (Exception e) {
      println("send: " + pipe + " is not an OutputPipe");
      println(e.toString());
      return ShellApp.appMiscError;
    }

    if (op == null) {
      println ("send: cannot access pipe" + pipe);
      return ShellApp.appMiscError;
    }

    /*
     * extract the mesg info
     */

    String m = args[1];

    obj = env.get (m);
    if (obj == null) {
      println ("send: cannot access " + m);
      return ShellApp.appMiscError;
    }

    Message msg = null;
    try {
      msg = (Message) obj.getObject();
    } catch (Exception e) {
      println("send: " + m + " is not a Message");
      println(e.toString());
      return ShellApp.appMiscError;
    }

    if (msg == null) {
      println ("send: cannot access msg" + m);
      return ShellApp.appMiscError;
    }

    // ok send the msg

    try {
	op.send (msg);
    } catch (Exception e) {
	println ("send: IOException");
	e.printStackTrace();
      return ShellApp.appMiscError;
    }

    return ShellApp.appNoError;
  }

  public String getDescription() {
      return "Send a message into a pipe";
  }

  public void help() {
      println("NAME");
      println("     send - send a message into a pipe");
      println(" ");
      println("SYNOPSIS");
      println("     send <output pipe> <msg>");
      println(" ");
      println("DESCRIPTION");
      println(" ");
      println("'send' sends a message into an output pipe. The output pipe needs");
      println("to have been previously created via a pipe advertisement.");
      println(" ");
      println("EXAMPLE");
      println(" ");
      println("    JXTA> pipeadv = newpipe -n mypipe");
      println("    JXTA> outpipe = mkpipe -o pipeadv");
      println("    JXTA> send outpipe msg");
      println(" ");
      println("This example creates a pipe advertisement 'pipeadv',");
      println("creates an output pipe 'outpipe' and sends the message 'msg'");
      println("through the pipe.");
      println(" ");
      println("SEE ALSO");
      println("    mkmsg put get recv mkadv newpipe mkpipe");
  }
}