dfsubscribeagent.java

JADE(JAVA Agent开发框架)是一个完全由JAVA语言开发的软件,它简化了多Agent系统的实现。

/**
 * ***************************************************************
 * JADE - Java Agent DEvelopment Framework is a framework to develop
 * multi-agent systems in compliance with the FIPA specifications.
 * Copyright (C) 2000 CSELT S.p.A.
 * 
 * GNU Lesser General Public License
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation,
 * version 2.1 of the License.
 * 
 * This library 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
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 * **************************************************************
 */
package examples.yellowPages;

import jade.core.Agent;
import jade.core.AID;
import jade.domain.DFService;
import jade.domain.FIPAException;
import jade.domain.FIPANames;
import jade.domain.FIPAAgentManagement.DFAgentDescription;
import jade.domain.FIPAAgentManagement.ServiceDescription;
import jade.domain.FIPAAgentManagement.Property;
import jade.domain.FIPAAgentManagement.SearchConstraints;
import jade.proto.SubscriptionInitiator;
import jade.lang.acl.ACLMessage;
import jade.util.leap.Iterator;

/**
   This example shows how to subscribe to the DF agent in order to be notified 
   each time a given service is published in the yellow pages catalogue.
   In this case in particular we want to be informed whenever a service of type
   "Weather-forecast" for Italy becomes available.
   @author Giovanni Caire - TILAB
 */
public class DFSubscribeAgent extends Agent {

  protected void setup() {
		// Build the description used as template for the subscription
		DFAgentDescription template = new DFAgentDescription();
		ServiceDescription templateSd = new ServiceDescription();
		templateSd.setType("weather-forecast");
		templateSd.addProperties(new Property("country", "Italy"));
		template.addServices(templateSd);
		
		SearchConstraints sc = new SearchConstraints();
		// We want to receive 10 results at most
		sc.setMaxResults(new Long(10));
  		
		addBehaviour(new SubscriptionInitiator(this, DFService.createSubscriptionMessage(this, getDefaultDF(), template, sc)) {
			protected void handleInform(ACLMessage inform) {
  			System.out.println("Agent "+getLocalName()+": Notification received from DF");
  			try {
					DFAgentDescription[] results = DFService.decodeNotification(inform.getContent());
		  		if (results.length > 0) {
		  			for (int i = 0; i < results.length; ++i) {
		  				DFAgentDescription dfd = results[i];
		  				AID provider = dfd.getName();
		  				// The same agent may provide several services; we are only interested
		  				// in the weather-forcast one
		  				Iterator it = dfd.getAllServices();
		  				while (it.hasNext()) {
		  					ServiceDescription sd = (ServiceDescription) it.next();
		  					if (sd.getType().equals("weather-forecast")) {
	  							System.out.println("Weather-forecast service for Italy found:");
		  						System.out.println("- Service \""+sd.getName()+"\" provided by agent "+provider.getName());
		  					}
		  				}
		  			}
		  		}	
	  			System.out.println();
		  	}
		  	catch (FIPAException fe) {
		  		fe.printStackTrace();
		  	}
			}
		} );
  } 
}