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.protocol;
michael@0: 
michael@0: import java.util.HashMap;
michael@0: 
michael@0: /**
michael@0:  * HttpContext represents execution state of an HTTP process. It is a structure
michael@0:  * that can be used to map an attribute name to an attribute value. Internally
michael@0:  * HTTP context implementations are usually backed by a {@link HashMap}.
michael@0:  * <p>
michael@0:  * The primary purpose of the HTTP context is to facilitate information sharing
michael@0:  * among various  logically related components. HTTP context can be used
michael@0:  * to store a processing state for one message or several consecutive messages.
michael@0:  * Multiple logically related messages can participate in a logical session
michael@0:  * if the same context is reused between consecutive messages.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public interface HttpContext {
michael@0: 
michael@0:     /** The prefix reserved for use by HTTP components. "http." */
michael@0:     public static final String RESERVED_PREFIX  = "http.";
michael@0: 
michael@0:     /**
michael@0:      * Obtains attribute with the given name.
michael@0:      *
michael@0:      * @param id the attribute name.
michael@0:      * @return attribute value, or <code>null</code> if not set.
michael@0:      */
michael@0:     Object getAttribute(String id);
michael@0: 
michael@0:     /**
michael@0:      * Sets value of the attribute with the given name.
michael@0:      *
michael@0:      * @param id the attribute name.
michael@0:      * @param obj the attribute value.
michael@0:      */
michael@0:     void setAttribute(String id, Object obj);
michael@0: 
michael@0:     /**
michael@0:      * Removes attribute with the given name from the context.
michael@0:      *
michael@0:      * @param id the attribute name.
michael@0:      * @return attribute value, or <code>null</code> if not set.
michael@0:      */
michael@0:     Object removeAttribute(String id);
michael@0: 
michael@0: }