content: /*
   * 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.activemq.transport.amqp.client.util;
  
  import java.io.IOException;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * Asynchronous Client Future class.
   */
  public class ClientFuture implements AsyncResult {
  
     private final AtomicBoolean completer = new AtomicBoolean();
     private final CountDownLatch latch = new CountDownLatch(1);
     private final ClientFutureSynchronization synchronization;
     private volatile Throwable error;
  
     public ClientFuture() {
        this(null);
     }
  
     public ClientFuture(ClientFutureSynchronization synchronization) {
        this.synchronization = synchronization;
     }
  
     @Override
     public boolean isComplete() {
        return latch.getCount() == 0;
     }
  
     @Override
     public void onFailure(Throwable result) {
        if (completer.compareAndSet(false, true)) {
           error = result;
           if (synchronization != null) {
              synchronization.onPendingFailure(error);
           }
           latch.countDown();
        }
     }
  
     @Override
     public void onSuccess() {
        if (completer.compareAndSet(false, true)) {
           if (synchronization != null) {
              synchronization.onPendingSuccess();
           }
           latch.countDown();
        }
     }
  
     /**
      * Timed wait for a response to a pending operation.
      *
      * @param amount The amount of time to wait before abandoning the wait.
      * @param unit   The unit to use for this wait period.
      * @throws IOException if an error occurs while waiting for the response.
      */
     public void sync(long amount, TimeUnit unit) throws IOException {
        try {
           latch.await(amount, unit);
        } catch (InterruptedException e) {
           Thread.interrupted();
           throw IOExceptionSupport.create(e);
        }
  
        failOnError();
     }
  
     /**
      * Waits for a response to some pending operation.
      *
      * @throws IOException if an error occurs while waiting for the response.
      */
     public void sync() throws IOException {
        try {
           latch.await();
        } catch (InterruptedException e) {
           Thread.interrupted();
           throw IOExceptionSupport.create(e);
        }
  
        failOnError();
     }
  
     private void failOnError() throws IOException {
        Throwable cause = error;
        if (cause != null) {
           throw IOExceptionSupport.create(cause);
        }
     }
  }
  