host.anzo.simon.PublishService Maven / Gradle / Ivy

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/*
 * Copyright (C) 2008 Alexander Christian . All rights reserved.
 *
 * This file is part of SIMON.
 *
 *   SIMON is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   SIMON is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with SIMON.  If not, see .
 */
package host.anzo.simon;

import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.SocketTimeoutException;
import java.util.List;

/**
 * TODO document me
 *
 * @author achr
 */
@Slf4j
public final class PublishService extends Thread {
	private MulticastSocket socket;
	private InetAddress groupAddress = InetAddress.getByName("239.1.2.3");
	private int groupPort = Simon.DEFAULT_PORT;
	private boolean shutdown;
	private List publishments;

	protected PublishService(List publishments) throws IOException {
		log.debug("preparing publish service");
		setName(Statics.PUBLISH_SERVICE_THREAD_NAME);
		socket = new MulticastSocket(groupPort);
		socket.joinGroup(groupAddress);
		socket.setSoTimeout(Statics.DEFAULT_SOCKET_TIMEOUT);
		this.publishments = publishments;
	}

	public void run() {
		log.debug("publish service up and running");
		while (!shutdown) {
			try {

				byte[] searchData = new byte[Statics.REQUEST_STRING.length()];
				DatagramPacket searchPacket = new DatagramPacket(searchData, searchData.length);
				socket.receive(searchPacket);

				InetAddress requestAddress = searchPacket.getAddress();
				int requestPort = searchPacket.getPort();
				String requestString = new String(searchPacket.getData());

				log.debug("got 'find server' request. requestHost=" + requestAddress + " requestPort=" + requestPort +
						" requestString=" + requestString);

				if (requestString.equals(Statics.REQUEST_STRING)) {

					// send answer pack to sender
					for (SimonPublication publishment : publishments) {
						log.debug("answering: " + publishment);
						byte[] answerData = publishment.toString().getBytes();
						DatagramPacket answerPacket = new DatagramPacket(answerData, answerData.length, requestAddress,
								groupPort - 1);
						socket.send(answerPacket);
					}
				}
			} catch (SocketTimeoutException e) {
				// do nothing on timeout
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		socket.close();
		log.debug("publish service terminated!");
	}

	protected void shutdown() {
		shutdown = true;
		log.debug("Shutting down the publish service now ...");
	}
}