マルチキャスト通信検証用

MulticastNode.java

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;

/**
 * マルチキャスト通信検証用
 * 各ホストでjarを起動してマルチキャスト通信が可能か検証する。
 * $ java -jar multicast.jar [message]
 */
public class MulticastNode {
	private static final String ADDRESS = "228.0.0.4";
	private static final int PORT = 60000;
	private InetAddress group;
	private MulticastSocket sock;

	public static void main(String[] args) throws IOException {
		if (args.length == 0) {
			System.out.println("Need an argument string to send.");
			System.exit(1);
		}

		String msg = args[0];

		System.out.printf("Sending message: %s\n", msg);

		MulticastNode node = new MulticastNode();

		node.send(msg);
		node.receive();
	}

	public MulticastNode() throws IOException {
		group = InetAddress.getByName(ADDRESS);
		sock = new MulticastSocket(PORT);
		sock.joinGroup(group);
	}

	public void send(String msg) throws IOException {
		DatagramPacket hi = new DatagramPacket(msg.getBytes(),
				msg.length(),
				group,
				PORT);
		sock.send(hi);
	}

	public void receive() throws IOException {
		byte[] buf;

		while (true) {
			buf = new byte[1000];
			DatagramPacket recv = new DatagramPacket(buf, buf.length);
			sock.receive(recv);
			System.out.printf("Received: %s\n", new String(buf));
		}
	}
}