/*
 * Copyright 2012 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat 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 2, or (at your
 * option) any later version.
 *
 * Thermostat 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 Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */


package com.redhat.thermostat.test;

import java.net.BindException;

public class FreePortFinder {


    public static interface TryPort {
        void tryPort(int port) throws Exception;
    }

    private static final int MIN_PORT = 1024;
    private static final int MAX_PORT = 49151;

    private static volatile int nextPort = MAX_PORT;

    public static int findFreePort(TryPort tryPort) throws Exception {
        int port;
        while (true) {
            try {
                port = nextPort();
                tryPort.tryPort(port);
                break;
            } catch (BindException ex) {
                continue;
            }
        }
        return port;
    }

    private static int nextPort() {
        nextPort++;
        if (nextPort > MAX_PORT) {
            nextPort = MIN_PORT;
        }
        return nextPort;
    }
}