001/* 002 * ==================================================================== 003 * Licensed to the Apache Software Foundation (ASF) under one 004 * or more contributor license agreements. See the NOTICE file 005 * distributed with this work for additional information 006 * regarding copyright ownership. The ASF licenses this file 007 * to you under the Apache License, Version 2.0 (the 008 * "License"); you may not use this file except in compliance 009 * with the License. You may obtain a copy of the License at 010 * 011 * http://www.apache.org/licenses/LICENSE-2.0 012 * 013 * Unless required by applicable law or agreed to in writing, 014 * software distributed under the License is distributed on an 015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 016 * KIND, either express or implied. See the License for the 017 * specific language governing permissions and limitations 018 * under the License. 019 * ==================================================================== 020 * 021 * This software consists of voluntary contributions made by many 022 * individuals on behalf of the Apache Software Foundation. For more 023 * information on the Apache Software Foundation, please see 024 * <http://www.apache.org/>. 025 * 026 */ 027 028package org.apache.http.protocol; 029 030/** 031 * HttpContext represents execution state of an HTTP process. It is a structure 032 * that can be used to map an attribute name to an attribute value. 033 * <p> 034 * The primary purpose of the HTTP context is to facilitate information sharing 035 * among various logically related components. HTTP context can be used 036 * to store a processing state for one message or several consecutive messages. 037 * Multiple logically related messages can participate in a logical session 038 * if the same context is reused between consecutive messages. 039 * <p>/ 040 * IMPORTANT: Please note HTTP context implementation, even when thread safe, 041 * may not be used concurrently by multiple threads, as the context may contain 042 * thread unsafe attributes. 043 * 044 * @since 4.0 045 */ 046public interface HttpContext { 047 048 /** The prefix reserved for use by HTTP components. "http." */ 049 public static final String RESERVED_PREFIX = "http."; 050 051 /** 052 * Obtains attribute with the given name. 053 * 054 * @param id the attribute name. 055 * @return attribute value, or {@code null} if not set. 056 */ 057 Object getAttribute(String id); 058 059 /** 060 * Sets value of the attribute with the given name. 061 * 062 * @param id the attribute name. 063 * @param obj the attribute value. 064 */ 065 void setAttribute(String id, Object obj); 066 067 /** 068 * Removes attribute with the given name from the context. 069 * 070 * @param id the attribute name. 071 * @return attribute value, or {@code null} if not set. 072 */ 073 Object removeAttribute(String id); 074 075}