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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 java.util.concurrent.ArrayBlockingQueue;
30  import java.util.concurrent.ExecutorService;
31  import java.util.concurrent.ThreadPoolExecutor;
32  import java.util.concurrent.TimeUnit;
33  
34  import org.apache.http.annotation.Contract;
35  import org.apache.http.annotation.ThreadingBehavior;
36  import org.apache.http.util.Args;
37  
38  /**
39   * Immediately schedules any incoming validation request. Relies on
40   * {@link CacheConfig} to configure the used {@link java.util.concurrent.ThreadPoolExecutor}.
41   *
42   * @since 4.3
43   */
44  @Contract(threading = ThreadingBehavior.SAFE)
45  public class ImmediateSchedulingStrategy implements SchedulingStrategy {
46  
47      private final ExecutorService executor;
48  
49      /**
50       * Uses a {@link java.util.concurrent.ThreadPoolExecutor} which is configured according to the
51       * given {@link CacheConfig}.
52       * @param cacheConfig specifies thread pool settings. See
53       * {@link CacheConfig#getAsynchronousWorkersMax()},
54       * {@link CacheConfig#getAsynchronousWorkersCore()},
55       * {@link CacheConfig#getAsynchronousWorkerIdleLifetimeSecs()},
56       * and {@link CacheConfig#getRevalidationQueueSize()}.
57       */
58      public ImmediateSchedulingStrategy(final CacheConfig cacheConfig) {
59          this(new ThreadPoolExecutor(
60                  cacheConfig.getAsynchronousWorkersCore(),
61                  cacheConfig.getAsynchronousWorkersMax(),
62                  cacheConfig.getAsynchronousWorkerIdleLifetimeSecs(),
63                  TimeUnit.SECONDS,
64                  new ArrayBlockingQueue<Runnable>(cacheConfig.getRevalidationQueueSize()))
65          );
66      }
67  
68      ImmediateSchedulingStrategy(final ExecutorService executor) {
69          this.executor = executor;
70      }
71  
72      @Override
73      public void schedule(final AsynchronousValidationRequest revalidationRequest) {
74          Args.notNull(revalidationRequest, "AsynchronousValidationRequest");
75          executor.execute(revalidationRequest);
76      }
77  
78      @Override
79      public void close() {
80          executor.shutdown();
81      }
82  
83      /**
84       * Visible for testing.
85       */
86      void awaitTermination(final long timeout, final TimeUnit unit) throws InterruptedException {
87          executor.awaitTermination(timeout, unit);
88      }
89  }