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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  
28  package org.apache.http.impl.client;
29  
30  import org.apache.http.HttpResponse;
31  import org.apache.http.HttpStatus;
32  import org.apache.http.annotation.Immutable;
33  import org.apache.http.client.ServiceUnavailableRetryStrategy;
34  import org.apache.http.protocol.HttpContext;
35  import org.apache.http.util.Args;
36  
37  /**
38   * Default implementation of the {@link ServiceUnavailableRetryStrategy} interface.
39   * that retries <code>503</code> (Service Unavailable) responses for a fixed number of times
40   * at a fixed interval.
41   *
42   * @since 4.2
43   */
44  @Immutable
45  public class DefaultServiceUnavailableRetryStrategy implements ServiceUnavailableRetryStrategy {
46  
47      /**
48       * Maximum number of allowed retries if the server responds with a HTTP code
49       * in our retry code list. Default value is 1.
50       */
51      private final int maxRetries;
52  
53      /**
54       * Retry interval between subsequent requests, in milliseconds. Default
55       * value is 1 second.
56       */
57      private final long retryInterval;
58  
59      public DefaultServiceUnavailableRetryStrategy(final int maxRetries, final int retryInterval) {
60          super();
61          Args.positive(maxRetries, "Max retries");
62          Args.positive(retryInterval, "Retry interval");
63          this.maxRetries = maxRetries;
64          this.retryInterval = retryInterval;
65      }
66  
67      public DefaultServiceUnavailableRetryStrategy() {
68          this(1, 1000);
69      }
70  
71      @Override
72      public boolean retryRequest(final HttpResponse response, final int executionCount, final HttpContext context) {
73          return executionCount <= maxRetries &&
74              response.getStatusLine().getStatusCode() == HttpStatus.SC_SERVICE_UNAVAILABLE;
75      }
76  
77      @Override
78      public long getRetryInterval() {
79          return retryInterval;
80      }
81  
82  }