1   /*
    2    * $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0.1/httpcore/src/main/java/org/apache/http/protocol/RequestConnControl.java $
    3    * $Revision: 744532 $
    4    * $Date: 2009-02-14 18:12:18 +0100 (Sat, 14 Feb 2009) $
    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.HttpRequestInterceptor;
   39   
   40   /**
   41    * RequestConnControl is responsible for adding <code>Connection</code> header 
   42    * to the outgoing requests, which is essential for managing persistence of 
   43    * <code>HTTP/1.0</code> connections. This interceptor is recommended for 
   44    * client side protocol processors.
   45    *
   46    *
   47    * @version $Revision: 744532 $
   48    * 
   49    * @since 4.0
   50    */
   51   public class RequestConnControl implements HttpRequestInterceptor {
   52   
   53       public RequestConnControl() {
   54           super();
   55       }
   56       
   57       public void process(final HttpRequest request, final HttpContext context) 
   58               throws HttpException, IOException {
   59           if (request == null) {
   60               throw new IllegalArgumentException("HTTP request may not be null");
   61           }
   62           
   63           String method = request.getRequestLine().getMethod();
   64           if (method.equalsIgnoreCase("CONNECT")) {
   65               return;
   66           }
   67           
   68           if (!request.containsHeader(HTTP.CONN_DIRECTIVE)) {
   69               // Default policy is to keep connection alive
   70               // whenever possible
   71               request.addHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_KEEP_ALIVE);
   72           }
   73       }
   74       
   75   }