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 were in preview)
62 * 13: no changes (switch expressions and text blocks in preview)
63 * 14: TBD
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 * @since 14
203 */
204 RELEASE_14;
205
206 // Note that when adding constants for newer releases, the
207 // behavior of latest() and latestSupported() must be updated too.
208
209 /**
210 * Returns the latest source version that can be modeled.
211 *
212 * @return the latest source version that can be modeled
213 */
214 public static SourceVersion latest() {
215 return RELEASE_14;
216 }
217
218 private static final SourceVersion latestSupported = getLatestSupported();
219
220 /*
221 * The integer version to enum constant mapping implemented by
222 * this method assumes the JEP 322: "Time-Based Release
223 * Versioning" scheme is in effect. This scheme began in JDK
224 * 10. If the JDK versioning scheme is revised, this method may
225 * need to be updated accordingly.
226 */
227 private static SourceVersion getLatestSupported() {
228 int intVersion = Runtime.version().feature();
229 return (intVersion >= 11) ?
230 valueOf("RELEASE_" + Math.min(14, intVersion)):
231 RELEASE_10;
232 }
233
234 /**
235 * Returns the latest source version fully supported by the
236 * current execution environment. {@code RELEASE_9} or later must
237 * be returned.
238 *
239 * @apiNote This method is included alongside {@link latest} to
240 * allow identification of situations where the language model API
241 * is running on a platform version different than the latest
242 * version modeled by the API. One way that sort of situation can
243 * occur is if an IDE or similar tool is using the API to model
244 * source version <i>N</i> while running on platform version
245 * (<i>N</i> - 1). Running in this configuration is
246 * supported by the API. Running an API on platform versions
247 * earlier than (<i>N</i> - 1) or later than <i>N</i>
248 * may or may not work as an implementation detail. If an
249 * annotation processor was generating code to run under the
250 * current execution environment, the processor should only use
251 * platform features up to the {@code latestSupported} release,
252 * which may be earlier than the {@code latest} release.
253 *
254 * @return the latest source version that is fully supported
255 */
256 public static SourceVersion latestSupported() {
257 return latestSupported;
258 }
259
260 /**
261 * Returns whether or not {@code name} is a syntactically valid
262 * identifier (simple name) or keyword in the latest source
263 * version. The method returns {@code true} if the name consists
264 * of an initial character for which {@link
265 * Character#isJavaIdentifierStart(int)} returns {@code true},
266 * followed only by characters for which {@link
267 * Character#isJavaIdentifierPart(int)} returns {@code true}.
268 * This pattern matches regular identifiers, keywords, restricted
269 * keywords, restricted identifiers and the literals {@code "true"},
270 * {@code "false"}, {@code "null"}.
271 *
272 * The method returns {@code false} for all other strings.
273 *
274 * @param name the string to check
275 * @return {@code true} if this string is a
276 * syntactically valid identifier or keyword, {@code false}
277 * otherwise.
278 */
279 public static boolean isIdentifier(CharSequence name) {
280 String id = name.toString();
281
282 if (id.length() == 0) {
283 return false;
284 }
285 int cp = id.codePointAt(0);
286 if (!Character.isJavaIdentifierStart(cp)) {
287 return false;
288 }
289 for (int i = Character.charCount(cp);
290 i < id.length();
291 i += Character.charCount(cp)) {
292 cp = id.codePointAt(i);
293 if (!Character.isJavaIdentifierPart(cp)) {
294 return false;
295 }
296 }
297 return true;
298 }
299
300 /**
301 * Returns whether or not {@code name} is a syntactically valid
302 * qualified name in the latest source version. Unlike {@link
303 * #isIdentifier isIdentifier}, this method returns {@code false}
304 * for keywords, boolean literals, and the null literal.
305 *
306 * This method returns {@code true} for <i>restricted
307 * keywords</i> and <i>restricted identifiers</i>
308 *
309 * @param name the string to check
310 * @return {@code true} if this string is a
311 * syntactically valid name, {@code false} otherwise.
312 * @jls 3.9 Keywords
313 * @jls 6.2 Names and Identifiers
314 */
315 public static boolean isName(CharSequence name) {
316 return isName(name, latest());
317 }
318
319 /**
320 * Returns whether or not {@code name} is a syntactically valid
321 * qualified name in the given source version. Unlike {@link
322 * #isIdentifier isIdentifier}, this method returns {@code false}
323 * for keywords, boolean literals, and the null literal.
324 *
325 * This method returns {@code true} for <i>restricted
326 * keywords</i> and <i>restricted identifiers</i>
327 *
328 * @param name the string to check
329 * @param version the version to use
330 * @return {@code true} if this string is a
331 * syntactically valid name, {@code false} otherwise.
332 * @jls 3.9 Keywords
333 * @jls 6.2 Names and Identifiers
334 * @since 9
335 */
336 public static boolean isName(CharSequence name, SourceVersion version) {
337 String id = name.toString();
338
339 for(String s : id.split("\\.", -1)) {
340 if (!isIdentifier(s) || isKeyword(s, version))
341 return false;
342 }
343 return true;
344 }
345
346 /**
347 * Returns whether or not {@code s} is a keyword, boolean literal,
348 * or null literal in the latest source version.
349 * This method returns {@code false} for <i>restricted
350 * keywords</i> and <i>restricted identifiers</i>.
351 *
352 * @param s the string to check
353 * @return {@code true} if {@code s} is a keyword, or boolean
354 * literal, or null literal, {@code false} otherwise.
355 * @jls 3.9 Keywords
356 * @jls 3.10.3 Boolean Literals
357 * @jls 3.10.7 The Null Literal
358 */
359 public static boolean isKeyword(CharSequence s) {
360 return isKeyword(s, latest());
361 }
362
363 /**
364 * Returns whether or not {@code s} is a keyword, boolean literal,
365 * or null literal in the given source version.
366 * This method returns {@code false} for <i>restricted
367 * keywords</i> and <i>restricted identifiers</i>.
368 *
369 * @param s the string to check
370 * @param version the version to use
371 * @return {@code true} if {@code s} is a keyword, or boolean
372 * literal, or null literal, {@code false} otherwise.
373 * @jls 3.9 Keywords
374 * @jls 3.10.3 Boolean Literals
375 * @jls 3.10.7 The Null Literal
376 * @since 9
377 */
378 public static boolean isKeyword(CharSequence s, SourceVersion version) {
379 String id = s.toString();
380 switch(id) {
381 // A trip through history
382 case "strictfp":
383 return version.compareTo(RELEASE_2) >= 0;
384
385 case "assert":
386 return version.compareTo(RELEASE_4) >= 0;
387
388 case "enum":
389 return version.compareTo(RELEASE_5) >= 0;
390
391 case "_":
392 return version.compareTo(RELEASE_9) >= 0;
393
394 // Keywords common across versions
395
396 // Modifiers
397 case "public": case "protected": case "private":
398 case "abstract": case "static": case "final":
399 case "transient": case "volatile": case "synchronized":
400 case "native":
401
402 // Declarations
403 case "class": case "interface": case "extends":
404 case "package": case "throws": case "implements":
405
406 // Primitive types and void
407 case "boolean": case "byte": case "char":
408 case "short": case "int": case "long":
409 case "float": case "double":
410 case "void":
411
412 // Control flow
413 case "if": case "else":
414 case "try": case "catch": case "finally":
415 case "do": case "while":
416 case "for": case "continue":
417 case "switch": case "case": case "default":
418 case "break": case "throw": case "return":
419
420 // Other keywords
421 case "this": case "new": case "super":
422 case "import": case "instanceof":
423
424 // Forbidden!
425 case "goto": case "const":
426
427 // literals
428 case "null": case "true": case "false":
429 return true;
430
431 default:
432 return false;
433 }
434 }
435 }