terminatenaplet.java

移动Agent编程工具Naplet

/* 
 * @<#> TerminateNaplet.java version 0.0.1, 1/1/2000
 *
 * THIS PROGRAM IS FREE SOFTWARE; YOU CAN DISTRIBUTE IT AND/OR
 * MODIFY IT UNDER THE TERMS OF THE GNU GENERAL PUBLIC LICENSE 
 * AS PUBLISHED BY THE FREE SOFTWARE FOUNDATION.
 *
 * THIS PROGRAM IS DISTRIBUTED IN THE HOPE THAT IT WILL BE USEFUL,
 * BUT WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED WARRANTY OF
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. SEE THE 
 * GNU GENERAL PUBLIC LICENSE FOR MORE DETAILS.
 *
 * Copyright (c) 2000 Wayne State University. All Rights Reserved.
 */

package terminate;


/**
 * * The <code>TerminateNaplet</code> class implements a dummy naplet 
 * that travels around the network, sleeping a while at each server.
 * The naplet will be terminated by its dispatcher.
 *
 * @version 0.0.1, 1/1/2000
 * @author C. Xu
 *
 */
import java.io.*;
import java.rmi.*;
import java.util.*;
import java.lang.reflect.*;

import naplet.*;
import naplet.itinerary.*;
import naplet.message.*;

public class TerminateNaplet extends Naplet {

      public TerminateNaplet(String[] servers)
	 throws InvalidNapletException, InvalidItineraryException {
	 this(null, servers, null);
      }

      public TerminateNaplet(String name, String[] servers) 
	 throws InvalidNapletException, InvalidItineraryException {
	 this(name, servers, null);
      }

      /**
       * Constructs a naplet
       * @param servers a list of servers to be visited
       * @param listener listener of the naplet waiting for results
       */
      public TerminateNaplet(String[] servers, NapletListener listener) 
	 throws InvalidNapletException, InvalidItineraryException {
	 this(null, servers, listener);
      }

      /**
       * Constructs a naplet, setting itinerary 
       * 
       * @param name Nick name of the naplet
       * @param servers A list of servers to be visitted
       * @param listener Listener of the naplet waiting for results
       */
      public TerminateNaplet(String name, String[] servers, NapletListener listener) 
	 throws InvalidNapletException, InvalidItineraryException {

	 super(name, listener); 
	 try {
	    Hashtable messages = new Hashtable( servers.length );
	    setNapletState( new ProtectedNapletState() );
	    getNapletState().set("message", messages);
	 } catch (NapletStateAccessException nsae) {
	    throw new InvalidNapletException("Naplet state initialization failure");
	 }
	
	 setItinerary ( new ICItinerary( servers ) );

      }

      /**
       * Entry point of a naplet at each server
       */
      public void onStart() throws InterruptedException {
	 String serverName;
			
	 serverName = getNapletContext().getServerURN().getHostName();

	 System.out.println( "Naplet " + this.getNapletID().toString() 
			     + " arrives at " + serverName);
			
	 System.out.println("Sleeping... ...");
	 Thread.sleep(30000);
	 System.out.println("Wakeup");

	 try {
	    getItinerary().travel( this );
	 } catch (NapletMigrateException nme) {
	    System.out.println(nme.getMessage());
	 }

	 System.out.println("End of Start()");
      }

      public void onInterrupt() {
	 MailBox mbox = this.getNapletContext().getMessenger().getMailBox(this.getNapletID());
	 try {
	    Message msg = mbox.getMessage();
	    switch (msg.getType()) {
	       case Message.TERMINATE:
		  System.out.println("I'm to be interrupted");
		  Message ack = new Message(Message.TERMINATE_ACK, 
					    this.getNapletID(), msg.getSender(), " Ack to terminate");
		  try {
		     this.getNapletContext().getMessenger().send(this.getNapletID(), msg.getSender(), ack);

		  } catch (NapletCommunicationException nce) {
		     System.out.println(nce.getMessage());
		  }

		  Thread.currentThread().interrupt();
	       case Message.SUSPEND:
	       case Message.RESUME:
	    }
	 } catch (InterruptedException ie){}
      }

      static void classFinalize() {
	 System.out.println("MyNaplet was finalized");
      }

      private class ICItinerary extends Itinerary {

	    public ICItinerary( String[] servers ) 
	       throws InvalidItineraryException {


	       Operable act = null; 

	       // seq(s0,s1,s2) 
	       setRoute( new SeqPattern(servers, act) );	

	       System.out.println("ICItinerary = " + getRoute().toString() );

	    }


      }

}