1 /*
2 * Copyright (c) 2005, 2019, 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 * 11: local-variable syntax for lambda parameters
61 * 12: no changes (switch expressions in preview)
62 * 13: no changes (switch expressions and text blocks in preview)
63 * 14: switch expressions
64 */
65
66 /**
67 * The original version.
68 *
69 * The language described in
70 * <cite>The Java™ Language Specification, First Edition</cite>.
71 */
72 RELEASE_0,
73
74 /**
75 * The version recognized by the Java Platform 1.1.
76 *
77 * The language is {@code RELEASE_0} augmented with nested classes as described in the 1.1 update to
78 * <cite>The Java™ Language Specification, First Edition</cite>.
79 */
80 RELEASE_1,
81
82 /**
83 * The version recognized by the Java 2 Platform, Standard Edition,
84 * v 1.2.
85 *
86 * The language described in
87 * <cite>The Java™ Language Specification,
88 * Second Edition</cite>, which includes the {@code
89 * strictfp} modifier.
90 */
91 RELEASE_2,
92
93 /**
94 * The version recognized by the Java 2 Platform, Standard Edition,
95 * v 1.3.
96 *
97 * No major changes from {@code RELEASE_2}.
98 */
99 RELEASE_3,
100
101 /**
102 * The version recognized by the Java 2 Platform, Standard Edition,
103 * v 1.4.
104 *
105 * Added a simple assertion facility.
106 */
107 RELEASE_4,
108
109 /**
110 * The version recognized by the Java 2 Platform, Standard
111 * Edition 5.0.
112 *
113 * The language described in
114 * <cite>The Java™ Language Specification,
115 * Third Edition</cite>. First release to support
116 * generics, annotations, autoboxing, var-args, enhanced {@code
117 * for} loop, and hexadecimal floating-point literals.
118 */
119 RELEASE_5,
120
121 /**
122 * The version recognized by the Java Platform, Standard Edition
123 * 6.
124 *
125 * No major changes from {@code RELEASE_5}.
126 */
127 RELEASE_6,
128
129 /**
130 * The version recognized by the Java Platform, Standard Edition
131 * 7.
132 *
133 * Additions in this release include, diamond syntax for
134 * constructors, {@code try}-with-resources, strings in switch,
135 * binary literals, and multi-catch.
136 * @since 1.7
137 */
138 RELEASE_7,
139
140 /**
141 * The version recognized by the Java Platform, Standard Edition
142 * 8.
143 *
144 * Additions in this release include lambda expressions and default methods.
145 * @since 1.8
146 */
147 RELEASE_8,
148
149 /**
150 * The version recognized by the Java Platform, Standard Edition
151 * 9.
152 *
153 * Additions in this release include modules and removal of a
154 * single underscore from the set of legal identifier names.
155 *
156 * @since 9
157 */
158 RELEASE_9,
159
160 /**
161 * The version recognized by the Java Platform, Standard Edition
162 * 10.
163 *
164 * Additions in this release include local-variable type inference
165 * ({@code var}).
166 *
167 * @since 10
168 */
169 RELEASE_10,
170
171 /**
172 * The version recognized by the Java Platform, Standard Edition
173 * 11.
174 *
175 * Additions in this release include local-variable syntax for
176 * lambda parameters.
177 *
178 * @since 11
179 */
180 RELEASE_11,
181
182 /**
183 * The version recognized by the Java Platform, Standard Edition
184 * 12.
185 *
186 * @since 12
187 */
188 RELEASE_12,
189
190 /**
191 * The version recognized by the Java Platform, Standard Edition
192 * 13.
193 *
194 * @since 13
195 */
196 RELEASE_13,
197
198 /**
199 * The version recognized by the Java Platform, Standard Edition
200 * 14.
201 *
202 * Additions in this release include switch expressions.
203 *
204 * @since 14
205 */
206 RELEASE_14;
207
208 // Note that when adding constants for newer releases, the
209 // behavior of latest() and latestSupported() must be updated too.
210
211 /**
212 * Returns the latest source version that can be modeled.
213 *
214 * @return the latest source version that can be modeled
215 */
216 public static SourceVersion latest() {
217 return RELEASE_14;
218 }
219
220 private static final SourceVersion latestSupported = getLatestSupported();
221
222 /*
223 * The integer version to enum constant mapping implemented by
224 * this method assumes the JEP 322: "Time-Based Release
225 * Versioning" scheme is in effect. This scheme began in JDK
226 * 10. If the JDK versioning scheme is revised, this method may
227 * need to be updated accordingly.
228 */
229 private static SourceVersion getLatestSupported() {
230 int intVersion = Runtime.version().feature();
231 return (intVersion >= 11) ?
232 valueOf("RELEASE_" + Math.min(14, intVersion)):
233 RELEASE_10;
234 }
235
236 /**
237 * Returns the latest source version fully supported by the
238 * current execution environment. {@code RELEASE_9} or later must
239 * be returned.
240 *
241 * @apiNote This method is included alongside {@link latest} to
242 * allow identification of situations where the language model API
243 * is running on a platform version different than the latest
244 * version modeled by the API. One way that sort of situation can
245 * occur is if an IDE or similar tool is using the API to model
246 * source version <i>N</i> while running on platform version
247 * (<i>N</i> - 1). Running in this configuration is
248 * supported by the API. Running an API on platform versions
249 * earlier than (<i>N</i> - 1) or later than <i>N</i>
250 * may or may not work as an implementation detail. If an
251 * annotation processor was generating code to run under the
252 * current execution environment, the processor should only use
253 * platform features up to the {@code latestSupported} release,
254 * which may be earlier than the {@code latest} release.
255 *
256 * @return the latest source version that is fully supported
257 */
258 public static SourceVersion latestSupported() {
259 return latestSupported;
260 }
261
262 /**
263 * Returns whether or not {@code name} is a syntactically valid
264 * identifier (simple name) or keyword in the latest source
265 * version. The method returns {@code true} if the name consists
266 * of an initial character for which {@link
267 * Character#isJavaIdentifierStart(int)} returns {@code true},
268 * followed only by characters for which {@link
269 * Character#isJavaIdentifierPart(int)} returns {@code true}.
270 * This pattern matches regular identifiers, keywords, restricted
271 * keywords, restricted identifiers and the literals {@code "true"},
272 * {@code "false"}, {@code "null"}.
273 *
274 * The method returns {@code false} for all other strings.
275 *
276 * @param name the string to check
277 * @return {@code true} if this string is a
278 * syntactically valid identifier or keyword, {@code false}
279 * otherwise.
280 */
281 public static boolean isIdentifier(CharSequence name) {
282 String id = name.toString();
283
284 if (id.length() == 0) {
285 return false;
286 }
287 int cp = id.codePointAt(0);
288 if (!Character.isJavaIdentifierStart(cp)) {
289 return false;
290 }
291 for (int i = Character.charCount(cp);
292 i < id.length();
293 i += Character.charCount(cp)) {
294 cp = id.codePointAt(i);
295 if (!Character.isJavaIdentifierPart(cp)) {
296 return false;
297 }
298 }
299 return true;
300 }
301
302 /**
303 * Returns whether or not {@code name} is a syntactically valid
304 * qualified name in the latest source version. Unlike {@link
305 * #isIdentifier isIdentifier}, this method returns {@code false}
306 * for keywords, boolean literals, and the null literal.
307 *
308 * This method returns {@code true} for <i>restricted
309 * keywords</i> and <i>restricted identifiers</i>
310 *
311 * @param name the string to check
312 * @return {@code true} if this string is a
313 * syntactically valid name, {@code false} otherwise.
314 * @jls 3.9 Keywords
315 * @jls 6.2 Names and Identifiers
316 */
317 public static boolean isName(CharSequence name) {
318 return isName(name, latest());
319 }
320
321 /**
322 * Returns whether or not {@code name} is a syntactically valid
323 * qualified name in the given source version. Unlike {@link
324 * #isIdentifier isIdentifier}, this method returns {@code false}
325 * for keywords, boolean literals, and the null literal.
326 *
327 * This method returns {@code true} for <i>restricted
328 * keywords</i> and <i>restricted identifiers</i>
329 *
330 * @param name the string to check
331 * @param version the version to use
332 * @return {@code true} if this string is a
333 * syntactically valid name, {@code false} otherwise.
334 * @jls 3.9 Keywords
335 * @jls 6.2 Names and Identifiers
336 * @since 9
337 */
338 public static boolean isName(CharSequence name, SourceVersion version) {
339 String id = name.toString();
340
341 for(String s : id.split("\\.", -1)) {
342 if (!isIdentifier(s) || isKeyword(s, version))
343 return false;
344 }
345 return true;
346 }
347
348 /**
349 * Returns whether or not {@code s} is a keyword, boolean literal,
350 * or null literal in the latest source version.
351 * This method returns {@code false} for <i>restricted
352 * keywords</i> and <i>restricted identifiers</i>.
353 *
354 * @param s the string to check
355 * @return {@code true} if {@code s} is a keyword, or boolean
356 * literal, or null literal, {@code false} otherwise.
357 * @jls 3.9 Keywords
358 * @jls 3.10.3 Boolean Literals
359 * @jls 3.10.7 The Null Literal
360 */
361 public static boolean isKeyword(CharSequence s) {
362 return isKeyword(s, latest());
363 }
364
365 /**
366 * Returns whether or not {@code s} is a keyword, boolean literal,
367 * or null literal in the given source version.
368 * This method returns {@code false} for <i>restricted
369 * keywords</i> and <i>restricted identifiers</i>.
370 *
371 * @param s the string to check
372 * @param version the version to use
373 * @return {@code true} if {@code s} is a keyword, or boolean
374 * literal, or null literal, {@code false} otherwise.
375 * @jls 3.9 Keywords
376 * @jls 3.10.3 Boolean Literals
377 * @jls 3.10.7 The Null Literal
378 * @since 9
379 */
380 public static boolean isKeyword(CharSequence s, SourceVersion version) {
381 String id = s.toString();
382 switch(id) {
383 // A trip through history
384 case "strictfp":
385 return version.compareTo(RELEASE_2) >= 0;
386
387 case "assert":
388 return version.compareTo(RELEASE_4) >= 0;
389
390 case "enum":
391 return version.compareTo(RELEASE_5) >= 0;
392
393 case "_":
394 return version.compareTo(RELEASE_9) >= 0;
395
396 // Keywords common across versions
397
398 // Modifiers
399 case "public": case "protected": case "private":
400 case "abstract": case "static": case "final":
401 case "transient": case "volatile": case "synchronized":
402 case "native":
403
404 // Declarations
405 case "class": case "interface": case "extends":
406 case "package": case "throws": case "implements":
407
408 // Primitive types and void
409 case "boolean": case "byte": case "char":
410 case "short": case "int": case "long":
411 case "float": case "double":
412 case "void":
413
414 // Control flow
415 case "if": case "else":
416 case "try": case "catch": case "finally":
417 case "do": case "while":
418 case "for": case "continue":
419 case "switch": case "case": case "default":
420 case "break": case "throw": case "return":
421
422 // Other keywords
423 case "this": case "new": case "super":
424 case "import": case "instanceof":
425
426 // Forbidden!
427 case "goto": case "const":
428
429 // literals
430 case "null": case "true": case "false":
431 return true;
432
433 default:
434 return false;
435 }
436 }
437 }