myapp.java

pastry的java实现的2.0b版

/*************************************************************************

"FreePastry" Peer-to-Peer Application Development Substrate 

Copyright 2002, Rice University. All rights reserved.

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********************************************************************************/
/*
 *  Created on Feb 15, 2005
 *
 *  TODO To change the template for this generated file go to
 *  Window - Preferences - Java - Code Style - Code Templates
 */
package rice.tutorial.appsocket;

import java.io.IOException;
import java.nio.ByteBuffer;

import rice.p2p.commonapi.*;
import rice.p2p.commonapi.appsocket.*;

/**
 * A very simple application.
 *
 * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
 * @author Jeff Hoye
 */
public class MyApp implements Application {
  /**
   * The Endpoint represents the underlieing node. By making calls on the
   * Endpoint, it assures that the message will be delivered to a MyApp on
   * whichever node the message is intended for.
   */
  protected Endpoint endpoint;

  /**
   * The node we were constructed on.
   */
  protected Node node;

  ByteBuffer[] outs;
  ByteBuffer out;

  ByteBuffer[] ins;
  ByteBuffer in;

  int MSG_LENGTH;

  /**
   * Constructor for MyApp.
   *
   * @param node DESCRIBE THE PARAMETER
   * @param factory DESCRIBE THE PARAMETER
   */
  public MyApp(Node node, final IdFactory factory) {
    // We are only going to use one instance of this application on each PastryNode
    this.endpoint = node.buildEndpoint(this, "myinstance");
    this.node = node;

    MSG_LENGTH = node.getLocalNodeHandle().getId().toByteArray().length;
    outs = new ByteBuffer[1];
    out = ByteBuffer.wrap(node.getLocalNodeHandle().getId().toByteArray());
    outs[0] = out;

    ins = new ByteBuffer[1];
    in = ByteBuffer.allocate(MSG_LENGTH);
    ins[0] = in;

    // example receiver interface
    endpoint.accept(
      new AppSocketReceiver() {

        /**
         * Called if we have a problem.
         *
         * @param socket DESCRIBE THE PARAMETER
         * @param e DESCRIBE THE PARAMETER
         */
        public void receiveException(AppSocket socket, Exception e) {
          e.printStackTrace();
        }

        public void receiveSelectResult(AppSocket socket, boolean canRead, boolean canWrite) {
          in.clear();
          try {
            long ret = socket.read(ins, 0, ins.length);

            if (ret != MSG_LENGTH) {
              // if you sent any kind of long message, you would need to handle this case better
              System.out.println("Error, we only received part of a message.");
              return;
            }

            System.out.println(MyApp.this.node.getLocalNodeHandle() + " Received message from " + factory.buildId(in.array()));
          } catch (IOException ioe) {
            ioe.printStackTrace();
          }
          // only need to do this if expecting more messages
//        socket.register(true, false, 3000, this);
        }

        /**
         * When we accept a new socket.
         *
         * @param socket DESCRIBE THE PARAMETER
         */
        public void receiveSocket(AppSocket socket) {
//        System.out.println("Accepted socket: "+socket);
          socket.register(true, false, 30000, this);

          // it's critical to call this to be able to accept multiple times
          endpoint.accept(this);
        }

      });

    endpoint.register();
  }

  /**
   * Getter for the node.
   *
   * @return The Node value
   */
  public Node getNode() {
    return node;
  }

  /**
   * Called to directly send a message to the nh
   *
   * @param nh DESCRIBE THE PARAMETER
   */
  public void sendMyMsgDirect(NodeHandle nh) {
    System.out.println(this + " opening to " + nh);
    endpoint.connect(nh,
      new AppSocketReceiver() {

        /**
         * Called if there is a problem.
         *
         * @param socket DESCRIBE THE PARAMETER
         * @param e DESCRIBE THE PARAMETER
         */
        public void receiveException(AppSocket socket, Exception e) {
          e.printStackTrace();
        }

        /**
         * Example of how to write some bytes
         *
         * @param socket DESCRIBE THE PARAMETER
         * @param canRead DESCRIBE THE PARAMETER
         * @param canWrite DESCRIBE THE PARAMETER
         */
        public void receiveSelectResult(AppSocket socket, boolean canRead, boolean canWrite) {
          try {
            long ret = socket.write(outs, 0, outs.length);
//          System.out.println("WROTE:"+ret);
            // see if we are done
            if (!out.hasRemaining()) {
              socket.close();
              out.clear();
            } else {
              // keep writing
              socket.register(false, true, 30000, this);
            }
          } catch (IOException ioe) {
            ioe.printStackTrace();
          }
        }

        /**
         * Called when the socket comes available.
         *
         * @param socket DESCRIBE THE PARAMETER
         */
        public void receiveSocket(AppSocket socket) {
//        System.out.println("Connected socket: "+socket);
          socket.register(false, true, 30000, this);
        }
      }, 30000);
  }

  /**
   * Called when we receive a message.
   *
   * @param id DESCRIBE THE PARAMETER
   * @param message DESCRIBE THE PARAMETER
   */
  public void deliver(Id id, Message message) {
    System.out.println(this + " received " + message);
  }

  /**
   * Called when you hear about a new neighbor. Don't worry about this method
   * for now.
   *
   * @param handle DESCRIBE THE PARAMETER
   * @param joined DESCRIBE THE PARAMETER
   */
  public void update(NodeHandle handle, boolean joined) {
  }

  /**
   * Called a message travels along your path. Don't worry about this method for
   * now.
   *
   * @param message DESCRIBE THE PARAMETER
   * @return DESCRIBE THE RETURN VALUE
   */
  public boolean forward(RouteMessage message) {
    return true;
  }

  /**
   * DESCRIBE THE METHOD
   *
   * @return DESCRIBE THE RETURN VALUE
   */
  public String toString() {
    return "MyApp " + endpoint.getId();
  }

}