primeclient.java

javaP2P技术内幕课程111213141516源代码

/*
 * Created by IntelliJ IDEA.
 * User: fsommers
 * Date: Apr 11, 2002
 * Time: 12:56:33 AM
 * To change template for new class use 
 * Code Style | Class Templates options (Tools | IDE Options).
 */
package primecruncher;

import net.jxta.document.StructuredTextDocument;

import javax.swing.*;
import java.awt.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

/**
 * A program that computes a list of prime numbers between two integers in a
 * distributed manner. It asynchronously discovers peers that advertise a
 * prime number searching service via a <code>ModuleSpecAdvertisement</code>.
 * When a user enters two integers, this program divides that list between all the
 * peers known to offer the prime searching functionality at the time. It then
 * opens a pipe to each such peer, and sends a message to each containing that peer's
 * segment boundary integers. That message also contains a <code>PipeAdvertisement</code>
 * to allow the prime seaching peer to send its response back to the requesting peer.
 * A prime searching peer computes the list of primes
 * between those boundary numbers, opens a pipe back to the requesting peer, and sends
 * a response message back, containing the computed list (as a comma-separated integer list).
 * The client peer waits for all peers to send back their responses, and it then
 * assembles the complete primes list from the partial results, and displays that list
 * back to the user.
 * This peer manages a cache of all known prime searching peers on the network. That list
 * is saved persistently.
 * For each
 * peer it finds, it periodically collects statistics about that peer. Statistics include the
 * peer's uptime, the number of message that peer processed, etc. It then scores each prime
 * searching peer according to those statistics. When a user submits a new search request,
 * the program favors peers with the best overall scores. When a request is distributed, this
 * peer will parcel out the complete list not equally, but according to the scores of the
 * intended target peers: Peers that perform better will receive a longer list, whereas
 * peers performing poorly will receive a shorter one.
 * When a message is sent to a peer, this peer notes the message that was sent, and the peer
 * to which the message was directed. When a response for a message is received, this peer
 * notes the time it took for the response to get back; it then takes that round-trip time,
 * plus the size of the list comprising that request to estimate the prime searching peer's
 * performance. That performance metrics is then taken into account at subsequent user
 * requests.
 * When a new requests is parcelled out, all known peers are utilized, regardless of their
 * performance metrics, if possible, to take advantage of parallelism.
 * When a message is sent out, there is no guarantee that an answer will be received. A time
 * boundary is set for how long to wait for a response. If a response is not received within
 * that boundary, the request will be discarded, and a new request for that list portion is
 * submitted to another peer. (HOW TO COMPUTE BOUNDARY?)
 * The <code>ResultListener</code> interface specifies a listener for prime results.
 * That listener is invoked when the results for a requested computation completes.
 */
public class PrimeClient extends JPanel implements ResultListener {


    //This object does the dispatching to other peers
    //It acts as a proxy for the prime cruching service
    private Dispatcher primeservice = null;

    private JTextArea results;
    private JTextArea status;

    /**
     * A graphical client for the prime-search service
     */
    public PrimeClient(Dispatcher disp) {
        primeservice = disp;
        buildGUI();
    }

    private void buildGUI() {

        setLayout(new BorderLayout());

        //top panel
        JPanel topPanel = new JPanel();
        topPanel.setLayout(new FlowLayout());
        final JTextField fromField = new JTextField(10);
        final JTextField toField = new JTextField(10);
        topPanel.add(new JLabel("From: "));
        topPanel.add(fromField);
        topPanel.add(new JLabel("To: "));
        topPanel.add(toField);

        status = new JTextArea(5, 20);
        results = new JTextArea(20, 20);
        JScrollPane scrollPane = new JScrollPane(results);
        JPanel centerPanel = new JPanel();
        centerPanel.setLayout(new BorderLayout());
        centerPanel.add(status, BorderLayout.NORTH);
        centerPanel.add(scrollPane, BorderLayout.CENTER);


       JButton goButton = new JButton("Go");
        JButton exitButton = new JButton("Exit");
        JPanel buttPanel = new JPanel();
        buttPanel.add(goButton);
        buttPanel.add(exitButton);



        add(topPanel, BorderLayout.NORTH);
        add(centerPanel, BorderLayout.CENTER);
        add(buttPanel, BorderLayout.SOUTH);

        goButton.addActionListener( new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String low = fromField.getText();
                String high = toField.getText();
                results.setText("");

                try {
                    int l = Integer.parseInt(low);
                    int h = Integer.parseInt(high);
                    primeservice.processPrimes(l, h, PrimeClient.this);
                } catch (NumberFormatException e1) {
                    status.setText("Wrong args");
                }
            }
        });

        exitButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });

    }

    private void displayResult(Result res) {
        results.append(res.toString());
    }

   public static void main(String[] args) {
       Dispatcher disp = new Dispatcher();
       PrimeClient app = new PrimeClient(disp);

       JFrame f = new JFrame("Prime cruncher");
       f.addWindowListener(new WindowAdapter() {
           public void windowClosing(WindowEvent e) {
               System.exit(0);

           }
       });
       f.getContentPane().add(app);
       f.pack();
       f.setVisible(true);
   }


     public void resultEvent(Result result) {
         displayResult(result);
    }

}