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    1   /*
    2    * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/DefaultHttpMethodRetryHandler.java,v 1.3 2004/12/20 11:47:46 olegk Exp $
    3    * $Revision: 480424 $
    4    * $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
    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 }