View Javadoc

1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  package org.apache.http.impl.client.cache;
28  
29  import org.apache.http.annotation.ThreadSafe;
30  import org.apache.http.util.Args;
31  
32  import java.util.concurrent.ArrayBlockingQueue;
33  import java.util.concurrent.ExecutorService;
34  import java.util.concurrent.ThreadPoolExecutor;
35  import java.util.concurrent.TimeUnit;
36  
37  /**
38   * Immediately schedules any incoming validation request. Relies on
39   * {@link CacheConfig} to configure the used {@link java.util.concurrent.ThreadPoolExecutor}.
40   *
41   * @since 4.3
42   */
43  @ThreadSafe
44  public class ImmediateSchedulingStrategy implements SchedulingStrategy {
45  
46      private final ExecutorService executor;
47  
48      /**
49       * Uses a {@link java.util.concurrent.ThreadPoolExecutor} which is configured according to the
50       * given {@link CacheConfig}.
51       * @param cacheConfig specifies thread pool settings. See
52       * {@link CacheConfig#getAsynchronousWorkersMax()},
53       * {@link CacheConfig#getAsynchronousWorkersCore()},
54       * {@link CacheConfig#getAsynchronousWorkerIdleLifetimeSecs()},
55       * and {@link CacheConfig#getRevalidationQueueSize()}.
56       */
57      public ImmediateSchedulingStrategy(final CacheConfig cacheConfig) {
58          this(new ThreadPoolExecutor(
59                  cacheConfig.getAsynchronousWorkersCore(),
60                  cacheConfig.getAsynchronousWorkersMax(),
61                  cacheConfig.getAsynchronousWorkerIdleLifetimeSecs(),
62                  TimeUnit.SECONDS,
63                  new ArrayBlockingQueue<Runnable>(cacheConfig.getRevalidationQueueSize()))
64          );
65      }
66  
67      ImmediateSchedulingStrategy(final ExecutorService executor) {
68          this.executor = executor;
69      }
70  
71      @Override
72      public void schedule(final AsynchronousValidationRequest revalidationRequest) {
73          Args.notNull(revalidationRequest, "AsynchronousValidationRequest");
74          executor.execute(revalidationRequest);
75      }
76  
77      @Override
78      public void close() {
79          executor.shutdown();
80      }
81  
82      /**
83       * Visible for testing.
84       */
85      void awaitTermination(final long timeout, final TimeUnit unit) throws InterruptedException {
86          executor.awaitTermination(timeout, unit);
87      }
88  }