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; 029 030import java.io.Serializable; 031 032import org.apache.http.annotation.ThreadingBehavior; 033import org.apache.http.annotation.Contract; 034import org.apache.http.util.Args; 035 036/** 037 * Represents a protocol version. The "major.minor" numbering 038 * scheme is used to indicate versions of the protocol. 039 * <p> 040 * This class defines a protocol version as a combination of 041 * protocol name, major version number, and minor version number. 042 * Note that {@link #equals} and {@link #hashCode} are defined as 043 * final here, they cannot be overridden in derived classes. 044 * </p> 045 * 046 * @since 4.0 047 */ 048@Contract(threading = ThreadingBehavior.IMMUTABLE) 049public class ProtocolVersion implements Serializable, Cloneable { 050 051 private static final long serialVersionUID = 8950662842175091068L; 052 053 054 /** Name of the protocol. */ 055 protected final String protocol; 056 057 /** Major version number of the protocol */ 058 protected final int major; 059 060 /** Minor version number of the protocol */ 061 protected final int minor; 062 063 064 /** 065 * Create a protocol version designator. 066 * 067 * @param protocol the name of the protocol, for example "HTTP" 068 * @param major the major version number of the protocol 069 * @param minor the minor version number of the protocol 070 */ 071 public ProtocolVersion(final String protocol, final int major, final int minor) { 072 this.protocol = Args.notNull(protocol, "Protocol name"); 073 this.major = Args.notNegative(major, "Protocol minor version"); 074 this.minor = Args.notNegative(minor, "Protocol minor version"); 075 } 076 077 /** 078 * Returns the name of the protocol. 079 * 080 * @return the protocol name 081 */ 082 public final String getProtocol() { 083 return protocol; 084 } 085 086 /** 087 * Returns the major version number of the protocol. 088 * 089 * @return the major version number. 090 */ 091 public final int getMajor() { 092 return major; 093 } 094 095 /** 096 * Returns the minor version number of the HTTP protocol. 097 * 098 * @return the minor version number. 099 */ 100 public final int getMinor() { 101 return minor; 102 } 103 104 105 /** 106 * Obtains a specific version of this protocol. 107 * This can be used by derived classes to instantiate themselves instead 108 * of the base class, and to define constants for commonly used versions. 109 * <p> 110 * The default implementation in this class returns {@code this} 111 * if the version matches, and creates a new {@link ProtocolVersion} 112 * otherwise. 113 * </p> 114 * 115 * @param major the major version 116 * @param minor the minor version 117 * 118 * @return a protocol version with the same protocol name 119 * and the argument version 120 */ 121 public ProtocolVersion forVersion(final int major, final int minor) { 122 123 if ((major == this.major) && (minor == this.minor)) { 124 return this; 125 } 126 127 // argument checking is done in the constructor 128 return new ProtocolVersion(this.protocol, major, minor); 129 } 130 131 132 /** 133 * Obtains a hash code consistent with {@link #equals}. 134 * 135 * @return the hashcode of this protocol version 136 */ 137 @Override 138 public final int hashCode() { 139 return this.protocol.hashCode() ^ (this.major * 100000) ^ this.minor; 140 } 141 142 143 /** 144 * Checks equality of this protocol version with an object. 145 * The object is equal if it is a protocl version with the same 146 * protocol name, major version number, and minor version number. 147 * The specific class of the object is <i>not</i> relevant, 148 * instances of derived classes with identical attributes are 149 * equal to instances of the base class and vice versa. 150 * 151 * @param obj the object to compare with 152 * 153 * @return {@code true} if the argument is the same protocol version, 154 * {@code false} otherwise 155 */ 156 @Override 157 public final boolean equals(final Object obj) { 158 if (this == obj) { 159 return true; 160 } 161 if (!(obj instanceof ProtocolVersion)) { 162 return false; 163 } 164 final ProtocolVersion that = (ProtocolVersion) obj; 165 166 return ((this.protocol.equals(that.protocol)) && 167 (this.major == that.major) && 168 (this.minor == that.minor)); 169 } 170 171 172 /** 173 * Checks whether this protocol can be compared to another one. 174 * Only protocol versions with the same protocol name can be 175 * {@link #compareToVersion compared}. 176 * 177 * @param that the protocol version to consider 178 * 179 * @return {@code true} if {@link #compareToVersion compareToVersion} 180 * can be called with the argument, {@code false} otherwise 181 */ 182 public boolean isComparable(final ProtocolVersion that) { 183 return (that != null) && this.protocol.equals(that.protocol); 184 } 185 186 187 /** 188 * Compares this protocol version with another one. 189 * Only protocol versions with the same protocol name can be compared. 190 * This method does <i>not</i> define a total ordering, as it would be 191 * required for {@link java.lang.Comparable}. 192 * 193 * @param that the protocol version to compare with 194 * 195 * @return a negative integer, zero, or a positive integer 196 * as this version is less than, equal to, or greater than 197 * the argument version. 198 * 199 * @throws IllegalArgumentException 200 * if the argument has a different protocol name than this object, 201 * or if the argument is {@code null} 202 */ 203 public int compareToVersion(final ProtocolVersion that) { 204 Args.notNull(that, "Protocol version"); 205 Args.check(this.protocol.equals(that.protocol), 206 "Versions for different protocols cannot be compared: %s %s", this, that); 207 int delta = getMajor() - that.getMajor(); 208 if (delta == 0) { 209 delta = getMinor() - that.getMinor(); 210 } 211 return delta; 212 } 213 214 215 /** 216 * Tests if this protocol version is greater or equal to the given one. 217 * 218 * @param version the version against which to check this version 219 * 220 * @return {@code true} if this protocol version is 221 * {@link #isComparable comparable} to the argument 222 * and {@link #compareToVersion compares} as greater or equal, 223 * {@code false} otherwise 224 */ 225 public final boolean greaterEquals(final ProtocolVersion version) { 226 return isComparable(version) && (compareToVersion(version) >= 0); 227 } 228 229 230 /** 231 * Tests if this protocol version is less or equal to the given one. 232 * 233 * @param version the version against which to check this version 234 * 235 * @return {@code true} if this protocol version is 236 * {@link #isComparable comparable} to the argument 237 * and {@link #compareToVersion compares} as less or equal, 238 * {@code false} otherwise 239 */ 240 public final boolean lessEquals(final ProtocolVersion version) { 241 return isComparable(version) && (compareToVersion(version) <= 0); 242 } 243 244 245 /** 246 * Converts this protocol version to a string. 247 * 248 * @return a protocol version string, like "HTTP/1.1" 249 */ 250 @Override 251 public String toString() { 252 final StringBuilder buffer = new StringBuilder(); 253 buffer.append(this.protocol); 254 buffer.append('/'); 255 buffer.append(Integer.toString(this.major)); 256 buffer.append('.'); 257 buffer.append(Integer.toString(this.minor)); 258 return buffer.toString(); 259 } 260 261 @Override 262 public Object clone() throws CloneNotSupportedException { 263 return super.clone(); 264 } 265 266}