jade2/src/BookBuyerAgent.java

package jadelab2;

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
{
	private BookBuyerGui myGui;
	private String targetBookTitle;

	private int budget = 128;

	//list of found sellers
	private AID[] sellerAgents;

	protected void setup()
	{
		targetBookTitle = "";
		System.out.println("Hello! " + getAID().getLocalName() + " is ready for the purchase order.");
		myGui = new BookBuyerGui(this);
		myGui.display();
		//time interval for buyer for sending subsequent CFP
		//as a CLI argument
		int interval = 20000;
		Object[] args = getArguments();
		if (args != null && args.length > 0) interval = Integer.parseInt(args[0].toString());
		addBehaviour(new TickerBehaviour(this, interval)
		{
			protected void onTick()
			{
				//search only if the purchase task was ordered
				if (!targetBookTitle.equals(""))
				{
					System.out.println(getAID().getLocalName() + ": I'm looking for " + targetBookTitle);
					//update a list of known sellers (DF)
					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(getAID().getLocalName() + ": the following sellers have been found");
						sellerAgents = new AID[result.length];
						for (int i = 0; i < result.length; ++i)
						{
							sellerAgents[i] = result[i].getName();
							System.out.println(sellerAgents[i].getLocalName());
						}
					}
					catch (FIPAException fe)
					{
						fe.printStackTrace();
					}

					myAgent.addBehaviour(new RequestPerformer());
				}
			}
		});
	}

	//invoked from GUI, when purchase was ordered
	public void lookForTitle(final String title)
	{
		addBehaviour(new OneShotBehaviour()
		{
			public void action()
			{
				targetBookTitle = title;
				System.out.println(getAID().getLocalName() + ": purchase order for " + targetBookTitle + " accepted");
			}
		});
	}

	protected void takeDown()
	{
		myGui.dispose();
		System.out.println("Buyer agent " + getAID().getLocalName() + " terminated.");
	}

	private class RequestPerformer extends Behaviour
	{
		private AID bestSeller;
		private int bestPrice;
		private int repliesCnt = 0;
		private MessageTemplate mt;
		private int step = 0;

		public void action()
		{
			switch (step)
			{
				case 0:
					//call for proposal (CFP) to found 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);
					mt = MessageTemplate.and(MessageTemplate.MatchConversationId("book-trade"),
					MessageTemplate.MatchInReplyTo(cfp.getReplyWith()));
					step = 1;
					break;
					case 1:
					//collect proposals
					ACLMessage reply = myAgent.receive(mt);
					if (reply != null)
					{
						if (reply.getPerformative() == ACLMessage.PROPOSE)
						{
							//proposal received
							int price = Integer.parseInt(reply.getContent());
							if (bestSeller == null || price < bestPrice)
							{
								//the best proposal as for now
								bestPrice = price;
								bestSeller = reply.getSender();
							}
						}
						repliesCnt++;
						if (repliesCnt >= sellerAgents.length)
						{
							//all proposals have been received
							step = 2; 
						}
					}
					else
					{
						block();
					}
					break;
				case 2:
					//best proposal consumption - purchase
					if(bestPrice > budget)
					{
						System.out.println(getAID().getLocalName() + ": Cannot buy: " + targetBookTitle + " for: " + bestPrice + ". It is more than budget: " + budget);
						step = 4;
						break;
					}
					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);
					mt = MessageTemplate.and(MessageTemplate.MatchConversationId("book-trade"),
					MessageTemplate.MatchInReplyTo(order.getReplyWith()));
					step = 3;
					break;
					case 3:      
					//seller confirms the transaction
					reply = myAgent.receive(mt);
					if (reply != null)
					{
						if (reply.getPerformative() == ACLMessage.INFORM)
						{
							//purchase succeeded
							System.out.println(getAID().getLocalName() + ": " + targetBookTitle + " purchased for " + bestPrice + " from " + reply.getSender().getLocalName());

							// Update budget
							budget = budget - bestPrice;
							System.out.println("Budget updated, left: " + budget);

							System.out.println(getAID().getLocalName() + ": waiting for the next purchase order.");
							targetBookTitle = "";
							//myAgent.doDelete();
						}
						else
						{
							System.out.println(getAID().getLocalName() + ": purchase has failed. " + targetBookTitle + " was sold in the meantime.");
						}
						step = 4;	//this state ends the purchase process
					}
					else
					{
						block();
					}
					break;
			}
		}

		public boolean done()
		{
			if (step == 2 && bestSeller == null)
			{
				System.out.println(getAID().getLocalName() + ": " + targetBookTitle + " is not on sale.");
			}
			//process terminates here if purchase has failed (title not on sale) or book was successfully bought 
			return ((step == 2 && bestSeller == null) || step == 4);
		}
	}

}