/*
 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/protocol/ResponseServer.java $
 * $Revision: 576073 $
 * $Date: 2007-09-16 03:53:13 -0700 (Sun, 16 Sep 2007) $
 *
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.protocol;

import java.io.IOException;

import org.apache.http.HttpException;
import org.apache.http.HttpResponse;
import org.apache.http.HttpResponseInterceptor;
import org.apache.http.params.CoreProtocolPNames;

/**
 * A response interceptor that adds a Server header.
 * For use on the server side.
 *
 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
 *
 * @version $Revision: 576073 $
 * 
 * @since 4.0
 */
public class ResponseServer implements HttpResponseInterceptor {

    public ResponseServer() {
        super();
    }

    public void process(final HttpResponse response, final HttpContext context) 
            throws HttpException, IOException {
        if (response == null) {
            throw new IllegalArgumentException("HTTP request may not be null");
        }
        if (!response.containsHeader(HTTP.SERVER_HEADER)) {
            String s = (String) response.getParams().getParameter(
                    CoreProtocolPNames.ORIGIN_SERVER);
            if (s != null) {
                response.addHeader(HTTP.SERVER_HEADER, s);
            }
        }
    }
    
}