/*
 * Copyright (C) 2008-2015 by Holger Arndt
 *
 * This file is part of the Universal Java Matrix Package (UJMP).
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership and licensing.
 *
 * UJMP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * UJMP 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with UJMP; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA  02110-1301  USA
 */

package org.ujmp.core.util;

import java.io.IOException;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

public abstract class NetworkUtil {

	public static final List getIPAddresses() throws SocketException {
		List ips = new ArrayList();
		Enumeration interfaces = NetworkInterface.getNetworkInterfaces();
		while (interfaces.hasMoreElements()) {
			NetworkInterface current = interfaces.nextElement();
			if (!current.isUp() || current.isLoopback() || current.isVirtual()) {
				continue;
			}
			Enumeration addresses = current.getInetAddresses();
			while (addresses.hasMoreElements()) {
				InetAddress currentAddress = addresses.nextElement();
				if (currentAddress.isLoopbackAddress()) {
					continue;
				}
				ips.add(currentAddress.getHostAddress());
			}
		}
		return ips;
	}

	public static int getRandomLocalPort() throws IOException {
		ServerSocket serverSocket = new ServerSocket(0);
		int port = serverSocket.getLocalPort();
		serverSocket.close();
		return port;
	}

	public static String getHostName(String address) {
		try {
			InetAddress addr = InetAddress.getByName(address);
			return addr.getHostName();
		} catch (UnknownHostException e) {
			return null;
		}
	}

}