001    /*
002     * SonarQube, open source software quality management tool.
003     * Copyright (C) 2008-2014 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * SonarQube is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * SonarQube is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public License
017     * along with this program; if not, write to the Free Software Foundation,
018     * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
019     */
020    package org.sonar.process;
021    
022    import org.apache.commons.io.IOUtils;
023    
024    import java.net.ServerSocket;
025    
026    public class NetworkUtils {
027    
028      private NetworkUtils() {
029        // only static stuff
030      }
031    
032      /**
033       * Get an unused port
034       */
035      public static int freePort() {
036        ServerSocket s = null;
037        try {
038          s = new ServerSocket(0);
039          return s.getLocalPort();
040        } catch (Exception e) {
041          throw new IllegalStateException("Can not find an open network port", e);
042        } finally {
043          IOUtils.closeQuietly(s);
044        }
045      }
046    }