helloworldapp.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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- Redistributions of source code must retain the above copyright
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- Redistributions in binary form must reproduce the above copyright
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- Neither  the name  of Rice  University (RICE) nor  the names  of its
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This software is provided by RICE and the contributors on an "as is"
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********************************************************************************/
package rice.pastry.testing;

import rice.environment.random.RandomSource;
import rice.pastry.*;
import rice.pastry.client.*;
import rice.pastry.messaging.*;
import rice.pastry.routing.*;

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

/**
 * A hello world example for pastry. This is the per-node app object.
 *
 * @version $Id: HelloWorldApp.java 3274 2006-05-15 16:17:47Z jeffh $
 * @author Sitaram Iyer
 */

public class HelloWorldApp extends PastryAppl {

  private int msgid = 0;

  private static int addr = HelloAddress.getCode();

  /**
   * Constructor for HelloWorldApp.
   *
   * @param pn DESCRIBE THE PARAMETER
   */
  public HelloWorldApp(PastryNode pn) {
    super(pn, null, addr, null);
    register();
  }

  // The remaining methods override abstract methods in the PastryAppl API.

  /**
   * Get address.
   *
   * @return the address of this application.
   */
  public int getAddress() {
    return addr;
  }

  /**
   * Sends a message to a randomly chosen node. Yeah, for fun.
   *
   * @param rng Randon number generator.
   */
  public void sendRndMsg(RandomSource rng) {
    Id rndid = Id.makeRandomId(rng);
    System.out.println("Sending message from " + getNodeId() + " to random dest " + rndid);
    Message msg = new HelloMsg(addr, thePastryNode.getLocalHandle(), rndid,
      ++msgid);
    routeMsg(rndid, msg, new SendOptions());
  }

  /**
   * Invoked on destination node when a message arrives.
   *
   * @param msg Message being routed around
   */
  public void messageForAppl(Message msg) {
    System.out.println("Received " + msg + " at " + getNodeId());
  }

  /**
   * Invoked on intermediate nodes in routing path.
   *
   * @param msg Message that's passing through this node.
   * @param key destination
   * @param nextHop next hop
   * @param opt send options
   * @return true if message needs to be forwarded according to plan.
   */
  public boolean enrouteMessage(Message msg, Id key, NodeHandle nextHop,
                                SendOptions opt) {
    System.out.println("Enroute " + msg + " at " + getNodeId());
    return true;
  }

  /**
   * Invoked upon change to leafset.
   *
   * @param nh node handle that got added/removed
   * @param wasAdded added (true) or removed (false)
   */
  public void leafSetChange(NodeHandle nh, boolean wasAdded) {
    String s = "In " + getNodeId() + "'s leaf set, " + "node " + nh.getNodeId()
      + " was ";
    if (wasAdded) {
      s += "added";
    } else {
      s += "removed";
    }

    System.out.println(s);
  }

  /**
   * Invoked upon change to routing table.
   *
   * @param nh node handle that got added/removed
   * @param wasAdded added (true) or removed (false)
   */
  public void routeSetChange(NodeHandle nh, boolean wasAdded) {
    String s = "In " + getNodeId() + "'s route set, " + "node "
      + nh.getNodeId() + " was ";
    if (wasAdded) {
      s += "added";
    } else {
      s += "removed";
    }

    System.out.println(s);
  }

  /**
   * Invoked by {RMI,Direct}PastryNode when the node has something in its leaf
   * set, and has become ready to receive application messages.
   */
  public void notifyReady() {
    if (true
    /*
     *  Log.ifp(6)
     */
      ) {
      System.out.println("Node " + getNodeId()
        + " ready, waking up any clients");
    }
    //sendRndMsg(new Randon());

  }

  /**
   * DESCRIBE THE CLASS
   *
   * @version $Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $
   * @author jeffh
   */
  private static class HelloAddress {
    private static int myCode = 0x1984abcd;

    /**
     * Gets the Code attribute of the HelloAddress class
     *
     * @return The Code value
     */
    public static int getCode() {
      return myCode;
    }
  }
}