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.http;
29
30 import org.apache.http.annotation.Contract;
31 import org.apache.http.annotation.ThreadingBehavior;
32
33 /**
34 * Represents an HTTP version. HTTP uses a "major.minor" numbering
35 * scheme to indicate versions of the protocol.
36 * <p>
37 * The version of an HTTP message is indicated by an HTTP-Version field
38 * in the first line of the message.
39 * </p>
40 * <pre>
41 * HTTP-Version = "HTTP" "/" 1*DIGIT "." 1*DIGIT
42 * </pre>
43 *
44 * @since 4.0
45 */
46 @Contract(threading = ThreadingBehavior.IMMUTABLE)
47 public final class HttpVersion extends ProtocolVersion {
48
49 private static final long serialVersionUID = -5856653513894415344L;
50
51 /** The protocol name. */
52 public static final String HTTP = "HTTP";
53
54 /** HTTP protocol version 0.9 */
55 public static final HttpVersion HTTP_0_9 = new HttpVersion(0, 9);
56
57 /** HTTP protocol version 1.0 */
58 public static final HttpVersion HTTP_1_0 = new HttpVersion(1, 0);
59
60 /** HTTP protocol version 1.1 */
61 public static final HttpVersion HTTP_1_1 = new HttpVersion(1, 1);
62
63
64 /**
65 * Create an HTTP protocol version designator.
66 *
67 * @param major the major version number of the HTTP protocol
68 * @param minor the minor version number of the HTTP protocol
69 *
70 * @throws IllegalArgumentException if either major or minor version number is negative
71 */
72 public HttpVersion(final int major, final int minor) {
73 super(HTTP, major, minor);
74 }
75
76
77 /**
78 * Obtains a specific HTTP version.
79 *
80 * @param major the major version
81 * @param minor the minor version
82 *
83 * @return an instance of {@link HttpVersion} with the argument version
84 */
85 @Override
86 public ProtocolVersion forVersion(final int major, final int minor) {
87
88 if ((major == this.major) && (minor == this.minor)) {
89 return this;
90 }
91
92 if (major == 1) {
93 if (minor == 0) {
94 return HTTP_1_0;
95 }
96 if (minor == 1) {
97 return HTTP_1_1;
98 }
99 }
100 if ((major == 0) && (minor == 9)) {
101 return HTTP_0_9;
102 }
103
104 // argument checking is done in the constructor
105 return new HttpVersion(major, minor);
106 }
107
108 }
109