/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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 org.apache.hadoop.hbase.net;
  
  import com.google.common.base.Supplier;
  import java.io.Closeable;
  import java.io.IOException;
  import java.net.InetAddress;
  import java.net.InetSocketAddress;
  import java.net.ServerSocket;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /**
   * Utility to generate a bound socket. Useful testing for BindException.
   * Use one of the Constructors to create an instance of this class. On creation it will have put
   * up a ServerSocket on a random port. Get the port it is bound to using {@link #getPort()}. In
   * your test, then try to start a Server using same port to generate a BindException. Call
   * {@link #close()} when done to shut down the Socket.
   */
  public final class BoundSocketMaker implements Closeable {
    private static final Log LOG = LogFactory.getLog(BoundSocketMaker.class);
    private final ServerSocket socket;
  
    private BoundSocketMaker() {
      this.socket = null;
    }
  
    public BoundSocketMaker(Supplier<Integer> randomPortMaker) {
      this(InetAddress.getLoopbackAddress().getHostName(), randomPortMaker);
    }
  
    public BoundSocketMaker(final String hostname, Supplier<Integer> randomPortMaker) {
      this.socket = get(hostname, randomPortMaker);
    }
  
    public int getPort() {
      return this.socket.getLocalPort();
    }
  
    /**
     * @return Returns a bound socket; be sure to close when done.
     */
    private ServerSocket get(String hostname, Supplier<Integer> randomPortMaker) {
      ServerSocket ss = null;
      int port = -1;
      while (true) {
        port = randomPortMaker.get();
        try {
          ss = new ServerSocket();
          ss.bind(new InetSocketAddress(hostname, port));
          break;
        } catch (IOException ioe) {
          LOG.warn("Failed bind", ioe);
          try {
            ss.close();
          } catch (IOException ioe2) {
            LOG.warn("FAILED CLOSE of failed bind socket", ioe2);
          }
        }
      }
      return ss;
    }
  
    @Override public void close() throws IOException {
      if (this.socket != null) {
        this.socket.close();
      }
    }
  }