michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib;
michael@0: 
michael@0: import java.io.IOException;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.protocol.HttpContext;
michael@0: 
michael@0: /**
michael@0:  * HTTP protocol interceptor is a routine that implements a specific aspect of
michael@0:  * the HTTP protocol. Usually protocol interceptors are expected to act upon
michael@0:  * one specific header or a group of related headers of the incoming message
michael@0:  * or populate the outgoing message with one specific header or a group of
michael@0:  * related headers.
michael@0:  * <p>
michael@0:  *  Protocol Interceptors can also manipulate content entities enclosed with messages.
michael@0:  * Usually this is accomplished by using the 'Decorator' pattern where a wrapper
michael@0:  * entity class is used to decorate the original entity.
michael@0:  * <p>
michael@0:  * Protocol interceptors must be implemented as thread-safe. Similarly to
michael@0:  * servlets, protocol interceptors should not use instance variables unless
michael@0:  * access to those variables is synchronized.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public interface HttpRequestInterceptor {
michael@0: 
michael@0:     /**
michael@0:      * Processes a request.
michael@0:      * On the client side, this step is performed before the request is
michael@0:      * sent to the server. On the server side, this step is performed
michael@0:      * on incoming messages before the message body is evaluated.
michael@0:      *
michael@0:      * @param request   the request to preprocess
michael@0:      * @param context   the context for the request
michael@0:      *
michael@0:      * @throws HttpException in case of an HTTP protocol violation
michael@0:      * @throws IOException in case of an I/O error
michael@0:      */
michael@0:     void process(HttpRequest request, HttpContext context)
michael@0:         throws HttpException, IOException;
michael@0: 
michael@0: }