1 /* 2 * Copyright (c) 2005, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package javax.lang.model; 27 28 import java.util.Collections; 29 import java.util.Set; 30 import java.util.HashSet; 31 32 /** 33 * Source versions of the Java™ programming language. 34 * 35 * See the appropriate edition of 36 * <cite>The Java™ Language Specification</cite> 37 * for information about a particular source version. 38 * 39 * <p>Note that additional source version constants will be added to 40 * model future releases of the language. 41 * 42 * @author Joseph D. Darcy 43 * @author Scott Seligman 44 * @author Peter von der Ahé 45 * @since 1.6 46 */ 47 public enum SourceVersion { 48 /* 49 * Summary of language evolution 50 * 1.1: nested classes 51 * 1.2: strictfp 52 * 1.3: no changes 53 * 1.4: assert 54 * 1.5: annotations, generics, autoboxing, var-args... 55 * 1.6: no changes 56 * 1.7: diamond syntax, try-with-resources, etc. 57 * 1.8: lambda expressions and default methods 58 * 9: modules, small cleanups to 1.7 and 1.8 changes 59 * 10: local-variable type inference (var) 60 */ 61 62 /** 63 * The original version. 64 * 65 * The language described in 66 * <cite>The Java™ Language Specification, First Edition</cite>. 67 */ 68 RELEASE_0, 69 70 /** 71 * The version recognized by the Java Platform 1.1. 72 * 73 * The language is {@code RELEASE_0} augmented with nested classes as described in the 1.1 update to 74 * <cite>The Java™ Language Specification, First Edition</cite>. 75 */ 76 RELEASE_1, 77 78 /** 79 * The version recognized by the Java 2 Platform, Standard Edition, 80 * v 1.2. 81 * 82 * The language described in 83 * <cite>The Java™ Language Specification, 84 * Second Edition</cite>, which includes the {@code 85 * strictfp} modifier. 86 */ 87 RELEASE_2, 88 89 /** 90 * The version recognized by the Java 2 Platform, Standard Edition, 91 * v 1.3. 92 * 93 * No major changes from {@code RELEASE_2}. 94 */ 95 RELEASE_3, 96 97 /** 98 * The version recognized by the Java 2 Platform, Standard Edition, 99 * v 1.4. 100 * 101 * Added a simple assertion facility. 102 */ 103 RELEASE_4, 104 105 /** 106 * The version recognized by the Java 2 Platform, Standard 107 * Edition 5.0. 108 * 109 * The language described in 110 * <cite>The Java™ Language Specification, 111 * Third Edition</cite>. First release to support 112 * generics, annotations, autoboxing, var-args, enhanced {@code 113 * for} loop, and hexadecimal floating-point literals. 114 */ 115 RELEASE_5, 116 117 /** 118 * The version recognized by the Java Platform, Standard Edition 119 * 6. 120 * 121 * No major changes from {@code RELEASE_5}. 122 */ 123 RELEASE_6, 124 125 /** 126 * The version recognized by the Java Platform, Standard Edition 127 * 7. 128 * 129 * Additions in this release include, diamond syntax for 130 * constructors, {@code try}-with-resources, strings in switch, 131 * binary literals, and multi-catch. 132 * @since 1.7 133 */ 134 RELEASE_7, 135 136 /** 137 * The version recognized by the Java Platform, Standard Edition 138 * 8. 139 * 140 * Additions in this release include lambda expressions and default methods. 141 * @since 1.8 142 */ 143 RELEASE_8, 144 145 /** 146 * The version recognized by the Java Platform, Standard Edition 147 * 9. 148 * 149 * Additions in this release include modules and removal of a 150 * single underscore from the set of legal identifier names. 151 * 152 * @since 9 153 */ 154 RELEASE_9, 155 156 /** 157 * The version recognized by the Java Platform, Standard Edition 158 * 10. 159 * 160 * Additions in this release include local-variable type inference 161 * ({@code var}). 162 * 163 * @since 10 164 */ 165 RELEASE_10; 166 167 // Note that when adding constants for newer releases, the 168 // behavior of latest() and latestSupported() must be updated too. 169 170 /** 171 * Returns the latest source version that can be modeled. 172 * 173 * @return the latest source version that can be modeled 174 */ 175 public static SourceVersion latest() { 176 return RELEASE_10; 177 } 178 179 private static final SourceVersion latestSupported = getLatestSupported(); 180 181 private static SourceVersion getLatestSupported() { 182 try { 183 String specVersion = System.getProperty("java.specification.version"); 184 185 switch (specVersion) { 186 case "10": 187 return RELEASE_10; 188 case "9": 189 return RELEASE_9; 190 case "1.8": 191 return RELEASE_8; 192 case "1.7": 193 return RELEASE_7; 194 case "1.6": 195 return RELEASE_6; 196 } 197 } catch (SecurityException se) {} 198 199 return RELEASE_5; 200 } 201 202 /** 203 * Returns the latest source version fully supported by the 204 * current execution environment. {@code RELEASE_5} or later must 205 * be returned. 206 * 207 * @return the latest source version that is fully supported 208 */ 209 public static SourceVersion latestSupported() { 210 return latestSupported; 211 } 212 213 /** 214 * Returns whether or not {@code name} is a syntactically valid 215 * identifier (simple name) or keyword in the latest source 216 * version. The method returns {@code true} if the name consists 217 * of an initial character for which {@link 218 * Character#isJavaIdentifierStart(int)} returns {@code true}, 219 * followed only by characters for which {@link 220 * Character#isJavaIdentifierPart(int)} returns {@code true}. 221 * This pattern matches regular identifiers, keywords, restricted 222 * keywords, and the literals {@code "true"}, {@code "false"}, and 223 * {@code "null"}. 224 * The method returns {@code false} for all other strings. 225 * 226 * @param name the string to check 227 * @return {@code true} if this string is a 228 * syntactically valid identifier or keyword, {@code false} 229 * otherwise. 230 */ 231 public static boolean isIdentifier(CharSequence name) { 232 String id = name.toString(); 233 234 if (id.length() == 0) { 235 return false; 236 } 237 int cp = id.codePointAt(0); 238 if (!Character.isJavaIdentifierStart(cp)) { 239 return false; 240 } 241 for (int i = Character.charCount(cp); 242 i < id.length(); 243 i += Character.charCount(cp)) { 244 cp = id.codePointAt(i); 245 if (!Character.isJavaIdentifierPart(cp)) { 246 return false; 247 } 248 } 249 return true; 250 } 251 252 /** 253 * Returns whether or not {@code name} is a syntactically valid 254 * qualified name in the latest source version. Unlike {@link 255 * #isIdentifier isIdentifier}, this method returns {@code false} 256 * for keywords, boolean literals, and the null literal. 257 * This method returns {@code true} for <i>restricted 258 * keywords</i>. 259 * 260 * @param name the string to check 261 * @return {@code true} if this string is a 262 * syntactically valid name, {@code false} otherwise. 263 * @jls 3.9 Keywords 264 * @jls 6.2 Names and Identifiers 265 */ 266 public static boolean isName(CharSequence name) { 267 return isName(name, latest()); 268 } 269 270 /** 271 * Returns whether or not {@code name} is a syntactically valid 272 * qualified name in the given source version. Unlike {@link 273 * #isIdentifier isIdentifier}, this method returns {@code false} 274 * for keywords, boolean literals, and the null literal. 275 * This method returns {@code true} for <i>restricted 276 * keywords</i>. 277 * 278 * @param name the string to check 279 * @param version the version to use 280 * @return {@code true} if this string is a 281 * syntactically valid name, {@code false} otherwise. 282 * @jls 3.9 Keywords 283 * @jls 6.2 Names and Identifiers 284 * @since 9 285 */ 286 public static boolean isName(CharSequence name, SourceVersion version) { 287 String id = name.toString(); 288 289 for(String s : id.split("\\.", -1)) { 290 if (!isIdentifier(s) || isKeyword(s, version)) 291 return false; 292 } 293 return true; 294 } 295 296 /** 297 * Returns whether or not {@code s} is a keyword, boolean literal, 298 * or null literal in the latest source version. 299 * This method returns {@code false} for <i>restricted 300 * keywords</i>. 301 * 302 * @param s the string to check 303 * @return {@code true} if {@code s} is a keyword, or boolean 304 * literal, or null literal, {@code false} otherwise. 305 * @jls 3.9 Keywords 306 * @jls 3.10.3 Boolean Literals 307 * @jls 3.10.7 The Null Literal 308 */ 309 public static boolean isKeyword(CharSequence s) { 310 return isKeyword(s, latest()); 311 } 312 313 /** 314 * Returns whether or not {@code s} is a keyword, boolean literal, 315 * or null literal in the given source version. 316 * This method returns {@code false} for <i>restricted 317 * keywords</i>. 318 * 319 * @param s the string to check 320 * @param version the version to use 321 * @return {@code true} if {@code s} is a keyword, or boolean 322 * literal, or null literal, {@code false} otherwise. 323 * @jls 3.9 Keywords 324 * @jls 3.10.3 Boolean Literals 325 * @jls 3.10.7 The Null Literal 326 * @since 9 327 */ 328 public static boolean isKeyword(CharSequence s, SourceVersion version) { 329 String id = s.toString(); 330 switch(id) { 331 // A trip through history 332 case "strictfp": 333 return version.compareTo(RELEASE_2) >= 0; 334 335 case "assert": 336 return version.compareTo(RELEASE_4) >= 0; 337 338 case "enum": 339 return version.compareTo(RELEASE_5) >= 0; 340 341 case "_": 342 return version.compareTo(RELEASE_9) >= 0; 343 344 // Keywords common across versions 345 346 // Modifiers 347 case "public": case "protected": case "private": 348 case "abstract": case "static": case "final": 349 case "transient": case "volatile": case "synchronized": 350 case "native": 351 352 // Declarations 353 case "class": case "interface": case "extends": 354 case "package": case "throws": case "implements": 355 356 // Primitive types and void 357 case "boolean": case "byte": case "char": 358 case "short": case "int": case "long": 359 case "float": case "double": 360 case "void": 361 362 // Control flow 363 case "if": case "else": 364 case "try": case "catch": case "finally": 365 case "do": case "while": 366 case "for": case "continue": 367 case "switch": case "case": case "default": 368 case "break": case "throw": case "return": 369 370 // Other keywords 371 case "this": case "new": case "super": 372 case "import": case "instanceof": 373 374 // Forbidden! 375 case "goto": case "const": 376 377 // literals 378 case "null": case "true": case "false": 379 return true; 380 381 default: 382 return false; 383 } 384 } 385 }