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      1 /*
      2  * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/protocol/RequestDate.java $
      3  * $Revision: 555989 $
      4  * $Date: 2007-07-13 06:33:39 -0700 (Fri, 13 Jul 2007) $
      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 
     32 package org.apache.http.protocol;
     33 
     34 import java.io.IOException;
     35 
     36 import org.apache.http.HttpException;
     37 import org.apache.http.HttpRequest;
     38 import org.apache.http.HttpEntityEnclosingRequest;
     39 import org.apache.http.HttpRequestInterceptor;
     40 
     41 /**
     42  * A request interceptor that adds a Date header.
     43  * For use on the client side.
     44  *
     45  * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
     46  *
     47  * @version $Revision: 555989 $
     48  *
     49  * @since 4.0
     50  */
     51 public class RequestDate implements HttpRequestInterceptor {
     52 
     53     private static final HttpDateGenerator DATE_GENERATOR = new HttpDateGenerator();
     54 
     55     public RequestDate() {
     56         super();
     57     }
     58 
     59     public void process(final HttpRequest request, final HttpContext context)
     60             throws HttpException, IOException {
     61         if (request == null) {
     62             throw new IllegalArgumentException
     63                 ("HTTP request may not be null.");
     64         }
     65         if ((request instanceof HttpEntityEnclosingRequest) &&
     66             !request.containsHeader(HTTP.DATE_HEADER)) {
     67             String httpdate = DATE_GENERATOR.getCurrentDate();
     68             request.setHeader(HTTP.DATE_HEADER, httpdate);
     69         }
     70     }
     71 
     72 }
     73