bookbuyeragent.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.bookTrading;

import jade.core.Agent;
import jade.core.AID;
import jade.core.behaviours.*;
import jade.lang.acl.ACLMessage;
import jade.lang.acl.MessageTemplate;
import jade.domain.DFService;
import jade.domain.FIPAException;
import jade.domain.FIPAAgentManagement.DFAgentDescription;
import jade.domain.FIPAAgentManagement.ServiceDescription;

public class BookBuyerAgent extends Agent {
  // The title of the book to buy
  private String targetBookTitle;
  // The list of known seller agents
  private AID[] sellerAgents;
  
  // Put agent initializations here
	protected void setup() {
	  // Printout a welcome message
	  System.out.println("Hallo! Buyer-agent "+getAID().getName()+" is ready.");
	    
	  // Get the title of the book to buy as a start-up argument
	  Object[] args = getArguments();
	  if (args != null && args.length > 0) {
	    targetBookTitle = (String) args[0];
	    System.out.println("Target book is "+targetBookTitle);
	
	    // Add a TickerBehaviour that schedules a request to seller agents every minute
	    addBehaviour(new TickerBehaviour(this, 60000) {
	      protected void onTick() {
			    System.out.println("Trying to buy "+targetBookTitle);
          // Update the list of seller agents
          DFAgentDescription template = new DFAgentDescription();
          ServiceDescription sd = new ServiceDescription();
          sd.setType("book-selling");
          template.addServices(sd);
          try {
          	DFAgentDescription[] result = DFService.search(myAgent, template); 
          	System.out.println("Found the following seller agents:");
            sellerAgents = new AID[result.length];
            for (int i = 0; i < result.length; ++i) {
              sellerAgents[i] = result[i].getName();
	          	System.out.println(sellerAgents[i].getName());
            }
          }
          catch (FIPAException fe) {
            fe.printStackTrace();
          }
          
          // Perform the request
	        myAgent.addBehaviour(new RequestPerformer());
	      }
	    } );
	  }
	  else {
	    // Make the agent terminate
	    System.out.println("No target book title specified");
	    doDelete();
	  }
	}

  // Put agent clean-up operations here
  protected void takeDown() {
    // Printout a dismissal message
    System.out.println("Buyer-agent "+getAID().getName()+" terminating.");
  }
  
	/**
	   Inner class RequestPerformer.
	   This is the behaviour used by Book-buyer agents to request seller 
	   agents the target book.
	 */
	private class RequestPerformer extends Behaviour {
	  private AID bestSeller; // The agent who provides the best offer 
	  private int bestPrice;  // The best offered price
	  private int repliesCnt = 0; // The counter of replies from seller agents
	  private MessageTemplate mt; // The template to receive replies
	  private int step = 0;
	
	  public void action() {
	    switch (step) {
	    case 0:
	      // Send the cfp to all sellers
	      ACLMessage cfp = new ACLMessage(ACLMessage.CFP);
	      for (int i = 0; i < sellerAgents.length; ++i) {
	        cfp.addReceiver(sellerAgents[i]);
	      } 
	      cfp.setContent(targetBookTitle);
	      cfp.setConversationId("book-trade");
	      cfp.setReplyWith("cfp"+System.currentTimeMillis()); // Unique value
	      myAgent.send(cfp);
	      // Prepare the template to get proposals
	      mt = MessageTemplate.and(MessageTemplate.MatchConversationId("book-trade"),
	                               MessageTemplate.MatchInReplyTo(cfp.getReplyWith()));
	      step = 1;
	      break;
	    case 1:
	      // Receive all proposals/refusals from seller agents
	      ACLMessage reply = myAgent.receive(mt);
	      if (reply != null) {
	        // Reply received
	        if (reply.getPerformative() == ACLMessage.PROPOSE) {
	          // This is an offer 
	          int price = Integer.parseInt(reply.getContent());
	          if (bestSeller == null || price < bestPrice) {
	            // This is the best offer at present
	            bestPrice = price;
	            bestSeller = reply.getSender();
	          }
	        }
	        repliesCnt++;
	        if (repliesCnt >= sellerAgents.length) {
	          // We received all replies
	          step = 2; 
	        }
	      }
	      else {
	        block();
	      }
	      break;
	    case 2:
	      // Send the purchase order to the seller that provided the best offer
	      ACLMessage order = new ACLMessage(ACLMessage.ACCEPT_PROPOSAL);
        order.addReceiver(bestSeller);
	      order.setContent(targetBookTitle);
	      order.setConversationId("book-trade");
	      order.setReplyWith("order"+System.currentTimeMillis());
	      myAgent.send(order);
	      // Prepare the template to get the purchase order reply
	      mt = MessageTemplate.and(MessageTemplate.MatchConversationId("book-trade"),
	                               MessageTemplate.MatchInReplyTo(order.getReplyWith()));
	      step = 3;
	      break;
	    case 3:      
	      // Receive the purchase order reply
	      reply = myAgent.receive(mt);
	      if (reply != null) {
	        // Purchase order reply received
	        if (reply.getPerformative() == ACLMessage.INFORM) {
	          // Purchase successful. We can terminate
	          System.out.println(targetBookTitle+" successfully purchased from agent "+reply.getSender().getName());
	          System.out.println("Price = "+bestPrice);
	          myAgent.doDelete();
	        }
	        else {
	          System.out.println("Attempt failed: requested book already sold.");
	        }
	        	
	        step = 4;
	      }
	      else {
	        block();
	      }
	      break;
	    }        
	  }
	
	  public boolean done() {
	  	if (step == 2 && bestSeller == null) {
	  		System.out.println("Attempt failed: "+targetBookTitle+" not available for sale");
	  	}
	    return ((step == 2 && bestSeller == null) || step == 4);
	  }
	}  // End of inner class RequestPerformer
}