//MulticastSendingThread是一個線程，它通過一個Multicast datagram來廣播消息。
package fish.server;

import java.io.*;
import java.net.*;

import fish.*;

public class MulticastSendingThread extends Thread {
	//消息數據
	private byte[] messageBytes;
	
	public MulticastSendingThread( byte[] bytes ) { 
		super( "MulticastSendingThread" );
		messageBytes = bytes; 
		}
	
	public void run() {
		//發送消息
		try {         
			//創建一個DatagramSocket來發送消息
			DatagramSocket socket = new DatagramSocket( 
					FishConstants.MULTICAST_SENDING_PORT );

			InetAddress group = InetAddress.getByName( 
					FishConstants.MULTICAST_ADDRESS );
      
			//創建一個包含消息的DatagramPacket
			DatagramPacket packet = new DatagramPacket( messageBytes, 
					messageBytes.length, group, FishConstants.MULTICAST_LISTENING_PORT );
			socket.send( packet );
			socket.close();
			} 
   
		catch ( IOException ioException ) { 
			ioException.printStackTrace();
			}
		} 
	
}