content: /*
   * Copyright (C) 2011 The Android Open Source Project
   *
   * 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 com.android.volley.mock;
  
  import com.android.volley.NetworkResponse;
  import com.android.volley.Request;
  import com.android.volley.Response;
  
  import java.util.concurrent.PriorityBlockingQueue;
  import java.util.concurrent.Semaphore;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  
  // TODO: the name of this class sucks
  @SuppressWarnings("serial")
  public class WaitableQueue extends PriorityBlockingQueue<Request<?>> {
      private final Request<?> mStopRequest = new MagicStopRequest();
      private final Semaphore mStopEvent = new Semaphore(0);
  
      // TODO: this isn't really "until empty" it's "until next call to take() after empty"
      public void waitUntilEmpty(long timeoutMillis)
              throws TimeoutException, InterruptedException {
          add(mStopRequest);
          if (!mStopEvent.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS)) {
              throw new TimeoutException();
          }
      }
  
      @Override
      public Request<?> take() throws InterruptedException {
          Request<?> item = super.take();
          if (item == mStopRequest) {
              mStopEvent.release();
              return take();
          }
          return item;
      }
  
      private static class MagicStopRequest extends Request<Object> {
          public MagicStopRequest() {
              super(Request.Method.GET, "", null);
          }
  
          @Override
          public Priority getPriority() {
              return Priority.LOW;
          }
  
          @Override
          protected Response<Object> parseNetworkResponse(NetworkResponse response) {
              return null;
          }
  
          @Override
          protected void deliverResponse(Object response) {
          }
      }
  }
  