import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;
 
public class BroadCastWord extends Frame implements ActionListener
{   
   int port;                                        
   InetAddress group=null;                          
   MulticastSocket socket=null;                     
   Timer time=null;                                 
   FileDialog open=null;                            
   Button select,開始廣播,停止廣播;
   File file=null;                                  
   String FileDir=null,fileName=null;
   FileReader in=null;                              
   BufferedReader bufferIn=null;
   int   token=0;                                   
   TextArea 顯示正在播放內容,顯示已播放的內容;       
  public BroadCastWord()
  {
   super("單詞廣播系統");
   select=new Button("選擇要廣播的文件");
   開始廣播=new Button("開始廣播");
   開始廣播.setEnabled(false);
   停止廣播=new Button("停止廣播");
   select.addActionListener(this); 
   開始廣播.addActionListener(this); 
   停止廣播.addActionListener(this); 
   time=new Timer(2000,this);                       
   open=new FileDialog(this,"選擇要廣播的文件",FileDialog.LOAD);  
   顯示正在播放內容=new TextArea(10,10);
   顯示正在播放內容.setForeground(Color.blue); 
   顯示已播放的內容=new TextArea(10,10);
   Panel north=new Panel();
   north.add(select);
   north.add(開始廣播);
   north.add(停止廣播);
   add(north,BorderLayout.NORTH);
   Panel center=new Panel();
   center.setLayout(new GridLayout(1,2)); 
   center.add(顯示正在播放內容);
   center.add(顯示已播放的內容);
   add(center,BorderLayout.CENTER);
   validate();
   try 
      {
       port=5000;                                   
       group=InetAddress.getByName("239.255.0.0");  
       socket=new MulticastSocket(port);            
       socket.setTimeToLive(1);                     
       socket.joinGroup(group);                     
                                                   
      } 
  catch(Exception e)
       {
         System.out.println("Error: "+ e);          
       }
  setBounds(100,50,360,380);   
  setVisible(true);
  addWindowListener(new WindowAdapter()
                     { public void windowClosing(WindowEvent e)
                       { System.exit(0);
      	               }
      	             });
 }
 public void actionPerformed(ActionEvent e)
 {
   if(e.getSource()==select)
     {
      顯示已播放的內容.setText(null);
      open.setVisible(true);
      fileName=open.getFile();
      FileDir=open.getDirectory(); 
      if(fileName!=null)
       { 
         time.stop();                                                
         file=new File(FileDir,fileName);
         try
            {
               file=new File(FileDir,fileName);
               in=new FileReader(file);                      
               bufferIn=new BufferedReader(in);
               開始廣播.setEnabled(true);  
            }
         catch(IOException ee)
            {
            }
       }
     }
   else if(e.getSource()==開始廣播)
     {
        time.start();
     }
   else if(e.getSource()==time)
     {
       String s=null;
        try
            {  
              if(token==-1)
                 {
                   file=new File(FileDir,fileName);
                   in=new FileReader(file);                      
                   bufferIn=new BufferedReader(in);
                 }
              s=bufferIn.readLine();
              if(s!=null)
                {
                  token=0;
                  顯示正在播放內容.setText("正在廣播的內容:\n"+s);
                  顯示已播放的內容.append(s+"\n");
                  DatagramPacket packet=null;                               
                  byte data[]=s.getBytes(); 
                  packet=new DatagramPacket(data,data.length,group,port); 
                  socket.send(packet);                                      
                }
              else
                {
                  token=-1;
                }
            }
        catch(IOException ee)
            {
            }
     }
   else if(e.getSource()==停止廣播)
     {
       time.stop();
     }
 }
                                         
 public static void main(String[] args) 
   {
      BroadCastWord broad=new BroadCastWord();
   }
}