001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.lang3; 018 019/** 020 * <p>An enum representing all the versions of the Java specification. 021 * This is intended to mirror available values from the 022 * <em>java.specification.version</em> System property. </p> 023 * 024 * @since 3.0 025 * @version $Id: JavaVersion.java 1654140 2015-01-23 08:41:18Z britter $ 026 */ 027public enum JavaVersion { 028 029 /** 030 * The Java version reported by Android. This is not an official Java version number. 031 */ 032 JAVA_0_9(1.5f, "0.9"), 033 034 /** 035 * Java 1.1. 036 */ 037 JAVA_1_1(1.1f, "1.1"), 038 039 /** 040 * Java 1.2. 041 */ 042 JAVA_1_2(1.2f, "1.2"), 043 044 /** 045 * Java 1.3. 046 */ 047 JAVA_1_3(1.3f, "1.3"), 048 049 /** 050 * Java 1.4. 051 */ 052 JAVA_1_4(1.4f, "1.4"), 053 054 /** 055 * Java 1.5. 056 */ 057 JAVA_1_5(1.5f, "1.5"), 058 059 /** 060 * Java 1.6. 061 */ 062 JAVA_1_6(1.6f, "1.6"), 063 064 /** 065 * Java 1.7. 066 */ 067 JAVA_1_7(1.7f, "1.7"), 068 069 /** 070 * Java 1.8. 071 */ 072 JAVA_1_8(1.8f, "1.8"), 073 074 /** 075 * Java 1.9. 076 */ 077 JAVA_1_9(1.9f, "1.9"), 078 079 /** 080 * Java 1.x, x > 9. Mainly introduced to avoid to break when a new version of Java is used. 081 */ 082 JAVA_RECENT(maxVersion(), Float.toString(maxVersion())); 083 084 /** 085 * The float value. 086 */ 087 private final float value; 088 /** 089 * The standard name. 090 */ 091 private final String name; 092 093 /** 094 * Constructor. 095 * 096 * @param value the float value 097 * @param name the standard name, not null 098 */ 099 JavaVersion(final float value, final String name) { 100 this.value = value; 101 this.name = name; 102 } 103 104 //----------------------------------------------------------------------- 105 /** 106 * <p>Whether this version of Java is at least the version of Java passed in.</p> 107 * 108 * <p>For example:<br> 109 * {@code myVersion.atLeast(JavaVersion.JAVA_1_4)}<p> 110 * 111 * @param requiredVersion the version to check against, not null 112 * @return true if this version is equal to or greater than the specified version 113 */ 114 public boolean atLeast(final JavaVersion requiredVersion) { 115 return this.value >= requiredVersion.value; 116 } 117 118 /** 119 * Transforms the given string with a Java version number to the 120 * corresponding constant of this enumeration class. This method is used 121 * internally. 122 * 123 * @param nom the Java version as string 124 * @return the corresponding enumeration constant or <b>null</b> if the 125 * version is unknown 126 */ 127 // helper for static importing 128 static JavaVersion getJavaVersion(final String nom) { 129 return get(nom); 130 } 131 132 /** 133 * Transforms the given string with a Java version number to the 134 * corresponding constant of this enumeration class. This method is used 135 * internally. 136 * 137 * @param nom the Java version as string 138 * @return the corresponding enumeration constant or <b>null</b> if the 139 * version is unknown 140 */ 141 static JavaVersion get(final String nom) { 142 if ("0.9".equals(nom)) { 143 return JAVA_0_9; 144 } else if ("1.1".equals(nom)) { 145 return JAVA_1_1; 146 } else if ("1.2".equals(nom)) { 147 return JAVA_1_2; 148 } else if ("1.3".equals(nom)) { 149 return JAVA_1_3; 150 } else if ("1.4".equals(nom)) { 151 return JAVA_1_4; 152 } else if ("1.5".equals(nom)) { 153 return JAVA_1_5; 154 } else if ("1.6".equals(nom)) { 155 return JAVA_1_6; 156 } else if ("1.7".equals(nom)) { 157 return JAVA_1_7; 158 } else if ("1.8".equals(nom)) { 159 return JAVA_1_8; 160 } else if ("1.9".equals(nom)) { 161 return JAVA_1_9; 162 } 163 if (nom == null) { 164 return null; 165 } 166 final float v = toFloatVersion(nom); 167 if ((v - 1.) < 1.) { // then we need to check decimals > .9 168 final int firstComma = Math.max(nom.indexOf('.'), nom.indexOf(',')); 169 final int end = Math.max(nom.length(), nom.indexOf(',', firstComma)); 170 if (Float.parseFloat(nom.substring(firstComma + 1, end)) > .9f) { 171 return JAVA_RECENT; 172 } 173 } 174 return null; 175 } 176 177 //----------------------------------------------------------------------- 178 /** 179 * <p>The string value is overridden to return the standard name.</p> 180 * 181 * <p>For example, <code>"1.5"</code>.</p> 182 * 183 * @return the name, not null 184 */ 185 @Override 186 public String toString() { 187 return name; 188 } 189 190 /** 191 * Gets the Java Version from the system or 2.0 if the {@code java.version} system property is not set. 192 * 193 * @return the value of {@code java.version} system property or 2.0 if it is not set. 194 */ 195 private static float maxVersion() { 196 final float v = toFloatVersion(System.getProperty("java.version", "2.0")); 197 if (v > 0) { 198 return v; 199 } 200 return 2f; 201 } 202 203 /** 204 * Parses a float value from a String. 205 * 206 * @param value the String to parse. 207 * @return the float value represented by teh string or -1 if the given String can not be parsed. 208 */ 209 private static float toFloatVersion(final String value) { 210 final String[] toParse = value.split("\\."); 211 if (toParse.length >= 2) { 212 try { 213 return Float.parseFloat(toParse[0] + '.' + toParse[1]); 214 } catch (final NumberFormatException nfe) { 215 // no-op, let use default 216 } 217 } 218 return -1; 219 } 220}