Event doesn't work in Java Jade

Question

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I have problem with event in Java. I have got two jade's class:

First class

import jade.core.Agent;
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;

import java.util.*;

public class BookSellerAgent extends Agent {
    // The catalogue of books for sale (maps the title of a book to its price)
    private Hashtable catalogue;
    // The GUI by means of which the user can add books in the catalogue
    private BookSellerGui myGui;

    // Put agent initializations here
    protected void setup() {
        // Create the catalogue
        catalogue = new Hashtable();

        // Create and show the GUI 
        myGui = new BookSellerGui(this);
        myGui.showGui();
        if(myGui.var==true)
            System.out.println("it is work");
        // Register the book-selling service in the yellow pages
        DFAgentDescription dfd = new DFAgentDescription();
        dfd.setName(getAID());
        ServiceDescription sd = new ServiceDescription();
        sd.setType("book-selling");
        sd.setName("JADE-book-trading");
        dfd.addServices(sd);
        try {
            DFService.register(this, dfd);
        }
        catch (FIPAException fe) {
            fe.printStackTrace();
        }

        // Add the behaviour serving queries from buyer agents
        addBehaviour(new OfferRequestsServer());

        // Add the behaviour serving purchase orders from buyer agents
        addBehaviour(new PurchaseOrdersServer());
    }

    // Put agent clean-up operations here
    protected void takeDown() {
        // Deregister from the yellow pages
        try {
            DFService.deregister(this);
        }
        catch (FIPAException fe) {
            fe.printStackTrace();
        }
        // Close the GUI
        myGui.dispose();
        // Printout a dismissal message
        System.out.println("Seller-agent "+getAID().getName()+" terminating.");
    }

    /**
     This is invoked by the GUI when the user adds a new book for sale
     */
    public void updateCatalogue(final String title, final int price) {
        addBehaviour(new OneShotBehaviour() {
            public void action() {
                catalogue.put(title, new Integer(price));
                System.out.println(title+" inserted into catalogue. Price = "+price);
            }
        } );
    }

    /**
       Inner class OfferRequestsServer.
       This is the behaviour used by Book-seller agents to serve incoming requests 
       for offer from buyer agents.
       If the requested book is in the local catalogue the seller agent replies 
       with a PROPOSE message specifying the price. Otherwise a REFUSE message is
       sent back.
     */
    private class OfferRequestsServer extends CyclicBehaviour {
        public void action() {
            MessageTemplate mt = MessageTemplate.MatchPerformative(ACLMessage.CFP);
            ACLMessage msg = myAgent.receive(mt);
            if (msg != null) {
                // CFP Message received. Process it
                String title = msg.getContent();
                ACLMessage reply = msg.createReply();

                Integer price = (Integer) catalogue.get(title);
                if (price != null) {
                    // The requested book is available for sale. Reply with the price
                    reply.setPerformative(ACLMessage.PROPOSE);
                    reply.setContent(String.valueOf(price.intValue()));
                }
                else {
                    // The requested book is NOT available for sale.
                    reply.setPerformative(ACLMessage.REFUSE);
                    reply.setContent("not-available");
                }
                myAgent.send(reply);
            }
            else {
                block();
            }
        }
    }  // End of inner class OfferRequestsServer

    /**
       Inner class PurchaseOrdersServer.
       This is the behaviour used by Book-seller agents to serve incoming 
       offer acceptances (i.e. purchase orders) from buyer agents.
       The seller agent removes the purchased book from its catalogue 
       and replies with an INFORM message to notify the buyer that the
       purchase has been sucesfully completed.
     */
    private class PurchaseOrdersServer extends CyclicBehaviour {
        public void action() {
            MessageTemplate mt = MessageTemplate.MatchPerformative(ACLMessage.ACCEPT_PROPOSAL);
            ACLMessage msg = myAgent.receive(mt);
            if (msg != null) {
                // ACCEPT_PROPOSAL Message received. Process it
                String title = msg.getContent();
                ACLMessage reply = msg.createReply();

                Integer price = (Integer) catalogue.remove(title);
                if (price != null) {
                    reply.setPerformative(ACLMessage.INFORM);
                    System.out.println(title+" sold to agent "+msg.getSender().getName());
                }
                else {
                    // The requested book has been sold to another buyer in the meanwhile .
                    reply.setPerformative(ACLMessage.FAILURE);
                    reply.setContent("not-available");
                }
                myAgent.send(reply);
            }
            else {
                block();
            }
        }
    }  // End of inner class OfferRequestsServer
}

Second class

import jade.core.AID;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
  @author Giovanni Caire - TILAB
 */
class BookSellerGui extends JFrame {    
        private BookSellerAgent myAgent;

    private JTextField titleField, priceField;
    boolean var;

    BookSellerGui(BookSellerAgent a) {
        super(a.getLocalName());

        myAgent = a;

        JPanel p = new JPanel();
        p.setLayout(new GridLayout(2, 2));
        p.add(new JLabel("Book title:"));
        titleField = new JTextField(15);
        p.add(titleField);
        p.add(new JLabel("Price:"));
        priceField = new JTextField(15);
        p.add(priceField);
        getContentPane().add(p, BorderLayout.CENTER);

        JButton addButton = new JButton("Add");
        addButton.addActionListener( new ActionListener() {
            public void actionPerformed(ActionEvent ev) {
                try {
                    String title = titleField.getText().trim();
                    String price = priceField.getText().trim();
                    myAgent.updateCatalogue(title, Integer.parseInt(price));
                    titleField.setText("");
                    priceField.setText("");
                    var=true;
                }
                catch (Exception e) {
                    JOptionPane.showMessageDialog(BookSellerGui.this, "Invalid values. "+e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE); 
                }
            }
        } );
        p = new JPanel();
        p.add(addButton);
        getContentPane().add(p, BorderLayout.SOUTH);

        // Make the agent terminate when the user closes 
        // the GUI using the button on the upper right corner   
        addWindowListener(new   WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                myAgent.doDelete();
            }
        } );

        setResizable(false);
    }

    public void showGui() {
        pack();
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        int centerX = (int)screenSize.getWidth() / 2;
        int centerY = (int)screenSize.getHeight() / 2;
        setLocation(centerX - getWidth() / 2, centerY - getHeight() / 2);
        super.setVisible(true);
    }   
}

Problem is that when I click Add in gui i want to view "it is work" . Why it doesn't work?

Answer 1

I don't know Jade but in your code, var is set to true when the add button is clicked. If you put a System.out.println("something") after the line var=true in the second class you will see that it happens as expected when you click the button.

If you change the first class like this:

if(myGui.var==true)
    System.out.println("it is work");
else
    System.out.println("Add button has not been pressed yet");

you will also see that var is still false when that condition is tested because you have not had time to click the add button yet.

The proper way to handle this would be to have the first class listen to the second class so that it gets alerted when the button is clicked and runs something appropriate when that happens.