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1   /**
2    * Licensed to jclouds, Inc. (jclouds) under one or more
3    * contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  jclouds licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.jclouds.http;
20  
21  /**
22   * Indicate whether a request should be retried after a server error response (HTTP status code >=
23   * 500) based on the request's replayable status and the number of attempts already performed.
24   * 
25   * @author James Murty
26   */
27  public interface HttpRetryHandler {
28     public static final HttpRetryHandler ALWAYS_RETRY = new HttpRetryHandler() {
29        public boolean shouldRetryRequest(HttpCommand command, HttpResponse response) {
30           return true;
31        }
32  
33        @Override
34        public String toString() {
35           return "ALWAYS_RETRY";
36        }
37     };
38  
39     public static final HttpRetryHandler NEVER_RETRY = new HttpRetryHandler() {
40        public boolean shouldRetryRequest(HttpCommand command, HttpResponse response) {
41           return false;
42        }
43  
44        @Override
45        public String toString() {
46           return "NEVER_RETRY";
47        }
48     };
49  
50     /**
51      * Return true if the command should be retried. This method should only be invoked when the
52      * response has failed with a HTTP 5xx error indicating a server-side error.
53      */
54     boolean shouldRetryRequest(HttpCommand command, HttpResponse response);
55  }