1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.hc.core5.http.protocol;
29
30 import org.apache.hc.core5.http.ProtocolVersion;
31
32 /**
33 * HttpContext represents execution state of an HTTP process. It is a structure
34 * that can be used to map an attribute name to an attribute value.
35 * <p>
36 * The primary purpose of the HTTP context is to facilitate information sharing
37 * among various logically related components. HTTP context can be used
38 * to store a processing state for one message or several consecutive messages.
39 * Multiple logically related messages can participate in a logical session
40 * if the same context is reused between consecutive messages.
41 * </p>
42 * <p>
43 * IMPORTANT: Please note HTTP context implementation, even when thread safe,
44 * may not be used concurrently by multiple threads, as the context may contain
45 * thread unsafe attributes.
46 * </p>
47 *
48 * @since 4.0
49 */
50 public interface HttpContext {
51
52 /** The prefix reserved for use by HTTP components. "http." */
53 String RESERVED_PREFIX = "http.";
54
55 /**
56 * Returns protocol version used in this context.
57 *
58 * @since 5.0
59 */
60 ProtocolVersion getProtocolVersion();
61
62 /**
63 * Sets protocol version used in this context.
64 *
65 * @since 5.0
66 */
67 void setProtocolVersion(ProtocolVersion version);
68
69 /**
70 * Obtains attribute with the given name.
71 *
72 * @param id the attribute name.
73 * @return attribute value, or {@code null} if not set.
74 */
75 Object getAttribute(String id);
76
77 /**
78 * Sets value of the attribute with the given name.
79 *
80 * @param id the attribute name.
81 * @param obj the attribute value.
82 * @return the previous value associated with <code>id</code>, or
83 * {@code null} if there was no mapping for <code>id</code>.
84 */
85 Object setAttribute(String id, Object obj);
86
87 /**
88 * Removes attribute with the given name from the context.
89 *
90 * @param id the attribute name.
91 * @return attribute value, or {@code null} if not set.
92 */
93 Object removeAttribute(String id);
94
95 }