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1   /*
2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/oac.hc3x/trunk/src/java/org/apache/commons/httpclient/DefaultHttpMethodRetryHandler.java $
3    * $Revision: 1425331 $
4    * $Date: 2012-12-22 19:29:41 +0100 (Sat, 22 Dec 2012) $
5    *
6    * ====================================================================
7    *
8    *  Licensed to the Apache Software Foundation (ASF) under one or more
9    *  contributor license agreements.  See the NOTICE file distributed with
10   *  this work for additional information regarding copyright ownership.
11   *  The ASF licenses this file to You under the Apache License, Version 2.0
12   *  (the "License"); you may not use this file except in compliance with
13   *  the License.  You may obtain a copy of the License at
14   *
15   *      http://www.apache.org/licenses/LICENSE-2.0
16   *
17   *  Unless required by applicable law or agreed to in writing, software
18   *  distributed under the License is distributed on an "AS IS" BASIS,
19   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20   *  See the License for the specific language governing permissions and
21   *  limitations under the License.
22   * ====================================================================
23   *
24   * This software consists of voluntary contributions made by many
25   * individuals on behalf of the Apache Software Foundation.  For more
26   * information on the Apache Software Foundation, please see
27   * <http://www.apache.org/>.
28   *
29   */
30  
31  package org.apache.commons.httpclient;
32  
33  import java.io.IOException;
34  import java.io.InterruptedIOException;
35  import java.net.NoRouteToHostException;
36  import java.net.UnknownHostException;
37  
38  /***
39   * The default {@link HttpMethodRetryHandler} used by {@link HttpMethod}s.
40   * 
41   * @author Michael Becke
42   * @author <a href="mailto:oleg -at- ural.ru">Oleg Kalnichevski</a>
43   */
44  public class DefaultHttpMethodRetryHandler implements HttpMethodRetryHandler {
45  
46  
47  	private static Class SSL_HANDSHAKE_EXCEPTION = null;
48  	
49  	static {
50  		try {
51  			SSL_HANDSHAKE_EXCEPTION = Class.forName("javax.net.ssl.SSLHandshakeException");
52  		} catch (ClassNotFoundException ignore) {			
53  		}
54  	}
55  	/*** the number of times a method will be retried */
56      private int retryCount;
57      
58      /*** Whether or not methods that have successfully sent their request will be retried */
59      private boolean requestSentRetryEnabled;
60      
61      /***
62       * Creates a new DefaultHttpMethodRetryHandler.
63       * @param retryCount the number of times a method will be retried
64       * @param requestSentRetryEnabled if true, methods that have successfully sent their request will be retried
65       */
66      public DefaultHttpMethodRetryHandler(int retryCount, boolean requestSentRetryEnabled) {
67          super();
68          this.retryCount = retryCount;
69          this.requestSentRetryEnabled = requestSentRetryEnabled;
70      }
71      
72      /***
73       * Creates a new DefaultHttpMethodRetryHandler that retries up to 3 times
74       * but does not retry methods that have successfully sent their requests.
75       */
76      public DefaultHttpMethodRetryHandler() {
77          this(3, false);
78      }
79      /*** 
80       * Used <code>retryCount</code> and <code>requestSentRetryEnabled</code> to determine
81       * if the given method should be retried.
82       * 
83       * @see HttpMethodRetryHandler#retryMethod(HttpMethod, IOException, int)
84       */
85      public boolean retryMethod(
86          final HttpMethod method, 
87          final IOException exception, 
88          int executionCount) {
89          if (method == null) {
90              throw new IllegalArgumentException("HTTP method may not be null");
91          }
92          if (exception == null) {
93              throw new IllegalArgumentException("Exception parameter may not be null");
94          }
95          // HttpMethod interface is the WORST thing ever done to HttpClient
96          if (method instanceof HttpMethodBase) {
97          	if (((HttpMethodBase)method).isAborted()) {
98                  return false;
99          	}
100         }
101         if (executionCount > this.retryCount) {
102             // Do not retry if over max retry count
103             return false;
104         }
105         if (exception instanceof NoHttpResponseException) {
106             // Retry if the server dropped connection on us
107             return true;
108         }
109         if (exception instanceof InterruptedIOException) {
110             // Timeout
111             return false;
112         }
113         if (exception instanceof UnknownHostException) {
114             // Unknown host
115             return false;
116         }
117         if (exception instanceof NoRouteToHostException) {
118             // Host unreachable
119             return false;
120         }
121         if (SSL_HANDSHAKE_EXCEPTION != null && SSL_HANDSHAKE_EXCEPTION.isInstance(exception)) {
122             // SSL handshake exception
123             return false;
124         }
125         if (!method.isRequestSent() || this.requestSentRetryEnabled) {
126             // Retry if the request has not been sent fully or
127             // if it's OK to retry methods that have been sent
128             return true;
129         }
130         // otherwise do not retry
131         return false;
132     }
133     
134     /***
135      * @return <code>true</code> if this handler will retry methods that have 
136      * successfully sent their request, <code>false</code> otherwise
137      */
138     public boolean isRequestSentRetryEnabled() {
139         return requestSentRetryEnabled;
140     }
141 
142     /***
143      * @return the maximum number of times a method will be retried
144      */
145     public int getRetryCount() {
146         return retryCount;
147     }
148 }