DefaultHttpRequestRetryHandler.java revision 417f3b92ba4549b2f22340e3107d869d2b9c5bb8 
1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/impl/client/DefaultHttpRequestRetryHandler.java $
3 * $Revision: 652726 $
4 * $Date: 2008-05-01 18:16:51 -0700 (Thu, 01 May 2008) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with 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,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.impl.client;
33
34import java.io.IOException;
35import java.io.InterruptedIOException;
36import java.net.UnknownHostException;
37
38import javax.net.ssl.SSLHandshakeException;
39
40import org.apache.http.NoHttpResponseException;
41import org.apache.http.client.HttpRequestRetryHandler;
42import org.apache.http.protocol.HttpContext;
43import org.apache.http.protocol.ExecutionContext;
44
45/**
46 * The default {@link HttpRequestRetryHandler} used by request executors.
47 *
48 * @author Michael Becke
49 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
50 */
51public class DefaultHttpRequestRetryHandler implements HttpRequestRetryHandler {
52
53    /** the number of times a method will be retried */
54    private final int retryCount;
55
56    /** Whether or not methods that have successfully sent their request will be retried */
57    private final boolean requestSentRetryEnabled;
58
59    /**
60     * Default constructor
61     */
62    public DefaultHttpRequestRetryHandler(int retryCount, boolean requestSentRetryEnabled) {
63        super();
64        this.retryCount = retryCount;
65        this.requestSentRetryEnabled = requestSentRetryEnabled;
66    }
67
68    /**
69     * Default constructor
70     */
71    public DefaultHttpRequestRetryHandler() {
72        this(3, false);
73    }
74    /**
75     * Used <code>retryCount</code> and <code>requestSentRetryEnabled</code> to determine
76     * if the given method should be retried.
77     */
78    public boolean retryRequest(
79            final IOException exception,
80            int executionCount,
81            final HttpContext context) {
82        if (exception == null) {
83            throw new IllegalArgumentException("Exception parameter may not be null");
84        }
85        if (context == null) {
86            throw new IllegalArgumentException("HTTP context may not be null");
87        }
88        if (executionCount > this.retryCount) {
89            // Do not retry if over max retry count
90            return false;
91        }
92        if (exception instanceof NoHttpResponseException) {
93            // Retry if the server dropped connection on us
94            return true;
95        }
96        if (exception instanceof InterruptedIOException) {
97            // Timeout
98            return false;
99        }
100        if (exception instanceof UnknownHostException) {
101            // Unknown host
102            return false;
103        }
104        if (exception instanceof SSLHandshakeException) {
105            // SSL handshake exception
106            return false;
107        }
108        Boolean b = (Boolean)
109            context.getAttribute(ExecutionContext.HTTP_REQ_SENT);
110        boolean sent = (b != null && b.booleanValue());
111        if (!sent || this.requestSentRetryEnabled) {
112            // Retry if the request has not been sent fully or
113            // if it's OK to retry methods that have been sent
114            return true;
115        }
116        // otherwise do not retry
117        return false;
118    }
119
120    /**
121     * @return <code>true</code> if this handler will retry methods that have
122     * successfully sent their request, <code>false</code> otherwise
123     */
124    public boolean isRequestSentRetryEnabled() {
125        return requestSentRetryEnabled;
126    }
127
128    /**
129     * @return the maximum number of times a method will be retried
130     */
131    public int getRetryCount() {
132        return retryCount;
133    }
134}
135