peerlist.java

高级java2 大学教程(含源码,经典的Java学习教程

// PeerList.java
// Initializes ServiceManager, starts service discovery
// and lists all IM services in a window
package com.deitel.advjhtp1.jini.IM;

// Java core packages
import java.awt.*;
import java.awt.event.*;
import java.net.MalformedURLException;
import java.util.*;
import java.util.List;
import java.io.IOException;
import java.rmi.*;

// Java extension packages
import javax.swing.*;
import javax.swing.event.*;

// Jini core packages
import net.jini.core.lookup.ServiceItem;
import net.jini.core.lookup.ServiceTemplate;
import net.jini.lookup.*;
import net.jini.discovery.LookupDiscoveryManager;
import net.jini.lease.LeaseRenewalManager;
import net.jini.lookup.entry.Name;
import net.jini.core.entry.Entry;
import net.jini.core.discovery.LookupLocator;

// Deitel Packages
import com.deitel.advjhtp1.jini.IM.service.IMService;
import com.deitel.advjhtp1.jini.IM.client.IMPeerListener;

public class PeerList extends JFrame 
   implements ServiceDiscoveryListener {
    
   private DefaultListModel peers;
   private JList peerList;
   private List serviceItems;
   private ServiceDiscoveryManager serviceDiscoveryManager;
   private LookupCache cache;
   private IMServiceManager myManager;
   private LookupDiscoveryManager lookupDiscoveryManager;

   // initialize userName to anonymous
   private String userName = "anonymous";

   // method called when ServiceDiscoveryManager finds 
   // IM service adds service proxy to serviceItems
   // adds Service name to ListModel for JList
   public void serviceAdded( ServiceDiscoveryEvent event )
   {
      // get added serviceItem
      ServiceItem item = event.getPostEventServiceItem();  
      Entry attributes[] = item.attributeSets;

      // iterates through attributes to find name
      for( int i = 0; i < attributes.length; i++ )

         if ( attributes[ i ] instanceof Name ) {
            System.out.println( "Added: " + item );
            serviceItems.add( item.service );             
            peers.addElement(
               ( ( Name )attributes[ i ] ).name );
               break;
         }  
   } // end method serviceAdded

   // empty method ignores seviceChanged event
   public void serviceChanged( ServiceDiscoveryEvent event )
   {}

   // removes services from PeerList GUI and data structure
   // when serviceRemoved event occurs
   public void serviceRemoved( ServiceDiscoveryEvent event )
   {
      // getPreEvent because item has been removed
      // getPostEvent would return null
      ServiceItem item = event.getPreEventServiceItem();
      Entry attributes[ ] = item.attributeSets;

      // debug
      System.out.println( "Remove Event!" );

      // remove from arraylist and DefaultListModel
      int index = serviceItems.indexOf( item.service );

      // print name of person removed
      if ( index >= 0 )
      {
         System.out.println( "Removing from List:" + 
            serviceItems.remove( index ));

         System.out.println( "Removing from DefList" +  
            peers.elementAt( index ) );
      
         peers.removeElementAt( index );
      }
   } // end method ServiceRemoved

   // constructor
   public PeerList()
   {
      super( "Peer List" );
      
      System.setSecurityManager( new RMISecurityManager() );

      // get desired userName
      userName = JOptionPane.showInputDialog( 
         PeerList.this, "Please enter your name: " );

      // change title of window
      setTitle( userName + "'s Peer List Window" );

      // Init Lists
      serviceItems = new ArrayList();

      Container container = getContentPane();
      peers = new DefaultListModel();

      // init components
      peerList = new JList( peers );
      peerList.setVisibleRowCount( 5 );
      JButton connectButton = new JButton( "Connect" );

      // do not allow multiple selections
      peerList.setSelectionMode(
         ListSelectionModel.SINGLE_SELECTION );

      // set up event handler for connectButton
      connectButton.addActionListener(
         new ActionListener() {
          
            public void actionPerformed( ActionEvent event )
            {
               int itemIndex = peerList.getSelectedIndex();

               Object selectedService = 
                  serviceItems.get( itemIndex );
               IMService peerProxy = 
                  ( IMService )selectedService;

               // send info to remote peer
               // get RMI reference
               try {
               
                  // set up gui and my peerImpl
                  IMPeerListener gui = 
                     new IMPeerListener( userName );
                  IMPeerImpl me = 
                     new IMPeerImpl( userName );
                  me.addListener( gui );

                  // Connect myGui to remote IMPeer object
                  IMPeer myPeer = peerProxy.connect( me );
                  gui.addPeer( myPeer );
               }

               // connecting may cause RemoteException
               catch( RemoteException re ) {
                  JOptionPane.showMessageDialog
                     ( null, "Couldn't Connect" );
                  re.printStackTrace();
               }
            }   
         }
      ); // end connectButton actionListener

      // set up File menu
      JMenu fileMenu = new JMenu( "File" );
      fileMenu.setMnemonic( 'F' );

      // about Item
      JMenuItem aboutItem = new JMenuItem( "About..." );
      aboutItem.setMnemonic( 'A' );
      aboutItem.addActionListener( 
         new ActionListener() {
            public void actionPerformed( ActionEvent event )
            {
               JOptionPane.showMessageDialog( PeerList.this, 
               "Deitel Instant Messenger" ,
               "About", JOptionPane.PLAIN_MESSAGE );
            }
         }
      );
            
      fileMenu.add( aboutItem );

      // AddLocator item
      JMenuItem federateItem = 
         new JMenuItem( "Add Locators" );
      federateItem.setMnemonic( 'L' );
      federateItem.addActionListener(
         
         new ActionListener() {
            public void actionPerformed( ActionEvent event )
            {  
               // get LookupService url to be added
               String locator = 
                  JOptionPane.showInputDialog( 
                     PeerList.this, 
                     "Please enter locator in this" +
                     "form: jini://host:port/" );
                  
               try {
                  LookupLocator newLocator = 
                     new LookupLocator( locator );
                   
                  // make one element LookupLocator array
                  LookupLocator[] locators = { newLocator };

                  // because addLocators takes array
                  lookupDiscoveryManager.addLocators( locators );
               }
                   
               catch( MalformedURLException urlException) {
               
                  JOptionPane.showMessageDialog( 
                     PeerList.this, "invalid url" );
               }
            }
         }
      );
      fileMenu.add( federateItem );

      // set up JMenuBar and attach File menu
      JMenuBar menuBar = new JMenuBar();
      menuBar.add ( fileMenu );
      setJMenuBar( menuBar );

      // handow window closing event
      addWindowListener(
         new WindowAdapter(){
            public void windowClosing( WindowEvent w )
            {
               System.out.println( "CLOSING WINDOW" );
               
               // disconnects from lookup services
               myManager.logout();
               System.exit( 0 );
             }
         }
      );       

      // lay out GUI components     
      peerList.setFixedCellWidth( 100 );
      JPanel inputPanel = new JPanel();
      inputPanel.add( connectButton );

      container.add( new JScrollPane( peerList ) ,
         BorderLayout.NORTH );
      container.add( inputPanel, BorderLayout.SOUTH );

      setSize( 100, 170 );
      setVisible( true );

      // peer list displays only other IMServices
      Class[] types = new Class[] { IMService.class };
      ServiceTemplate IMTemplate = 
         new ServiceTemplate( null, types, null );

      // Initialize IMServiceManager, ServiceDiscoveryManager
      try {
         myManager = new IMServiceManager( userName );  

         // store LookupDiscoveryManager 
         // generated by IMServiceManager
         lookupDiscoveryManager = myManager.getDiscoveryManager();

         // ServiceDiscoveryManager uses lookupDiscoveryManager
         serviceDiscoveryManager = 
            new ServiceDiscoveryManager( lookupDiscoveryManager,
               null );

         // create a LookupCache
         cache = serviceDiscoveryManager.createLookupCache(
            IMTemplate, null, this );
      }
       
      // catch all exceptions and inform user of problem
      catch ( Exception managerException) {
         JOptionPane.showMessageDialog( null, 
            "Error initializing IMServiceManger" +
            "or ServiceDisoveryManager" );
         managerException.printStackTrace();
      }
   }
   
   public static void main( String args[] )
   {
      new PeerList();
   }
}

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