// 儅儖僠僉儍僗僩僷働僢僩庴怣僾儘僌儔儉Mlisten.java
// 偙偺僾儘僌儔儉偼,儅儖僠僉儍僗僩僷働僢僩傪庴怣偟傑偡
// 巊偄曽java Mlisten [儅儖僠僉儍僗僩傾僪儗僗] [億乕僩斣崋]

// 儔僀僽儔儕偺棙梡
import java.net.*;
import java.io.*;

// Mlisten僋儔僗
public class Mlisten {
	// 張棟偺杮懱
	public static void main(String[] arg){
		String multicastAddress = "224.0.0.1" ;
				// 儅儖僠僉儍僗僩傾僪儗僗224.0.0.1偼,
				// 儖乕僞傪墇偊側偄応崌偺傾僪儗僗偱偡
		int port = 6000 ;
				// 僠儍僢僩梡偺億乕僩斣崋,巜掕偑側偗傟偽6000 斣偲偟傑偡
		byte[] buff = new byte[1024] ;
		if(arg.length >= 1) multicastAddress = arg[0] ;
		if(arg.length >= 2) port = Integer.parseInt(arg[1]) ;
		try{
			InetAddress chatgroup
				= InetAddress.getByName(multicastAddress) ;
			MulticastSocket soc = new MulticastSocket(port) ;
			soc.joinGroup(chatgroup) ;
			while(true){
				DatagramPacket recv
					= new DatagramPacket(buff,buff.length) ;
				soc.receive(recv) ;
				if(recv.getLength() > 0){
					System.out.write(buff,0,recv.getLength()) ;
				}
			}
		}catch(Exception e){
			e.printStackTrace() ;
			System.exit(1) ;
		}
	}
}