PortDetector.java

/*
 * Copyright © 2014 Cask Data, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package co.cask.cdap.common.utils;

import java.io.IOException;
import java.net.Socket;

/**
 * Class for help finding network ports.
 */
public class PortDetector {

  /**
   * Utility to find a free port to use for a server.
   *
   * @return a free port number
   * @throws java.io.IOException if any socket exception occurs
   */
  public static int findFreePort() throws IOException {
    Socket socket = new Socket();
    socket.bind(null);
    int port = socket.getLocalPort();
    socket.close();
    return port;
  }
}