1 /*
2 * Copyright (c) 2005, 2018, 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: to be determined changes
61 */
62
63 /**
64 * The original version.
65 *
66 * The language described in
67 * <cite>The Java™ Language Specification, First Edition</cite>.
68 */
69 RELEASE_0,
70
71 /**
72 * The version recognized by the Java Platform 1.1.
73 *
74 * The language is {@code RELEASE_0} augmented with nested classes as described in the 1.1 update to
75 * <cite>The Java™ Language Specification, First Edition</cite>.
76 */
77 RELEASE_1,
78
79 /**
80 * The version recognized by the Java 2 Platform, Standard Edition,
81 * v 1.2.
82 *
83 * The language described in
84 * <cite>The Java™ Language Specification,
85 * Second Edition</cite>, which includes the {@code
86 * strictfp} modifier.
87 */
88 RELEASE_2,
89
90 /**
91 * The version recognized by the Java 2 Platform, Standard Edition,
92 * v 1.3.
93 *
94 * No major changes from {@code RELEASE_2}.
95 */
96 RELEASE_3,
97
98 /**
99 * The version recognized by the Java 2 Platform, Standard Edition,
100 * v 1.4.
101 *
102 * Added a simple assertion facility.
103 */
104 RELEASE_4,
105
106 /**
107 * The version recognized by the Java 2 Platform, Standard
108 * Edition 5.0.
109 *
110 * The language described in
111 * <cite>The Java™ Language Specification,
112 * Third Edition</cite>. First release to support
113 * generics, annotations, autoboxing, var-args, enhanced {@code
114 * for} loop, and hexadecimal floating-point literals.
115 */
116 RELEASE_5,
117
118 /**
119 * The version recognized by the Java Platform, Standard Edition
120 * 6.
121 *
122 * No major changes from {@code RELEASE_5}.
123 */
124 RELEASE_6,
125
126 /**
127 * The version recognized by the Java Platform, Standard Edition
128 * 7.
129 *
130 * Additions in this release include, diamond syntax for
131 * constructors, {@code try}-with-resources, strings in switch,
132 * binary literals, and multi-catch.
133 * @since 1.7
134 */
135 RELEASE_7,
136
137 /**
138 * The version recognized by the Java Platform, Standard Edition
139 * 8.
140 *
141 * Additions in this release include lambda expressions and default methods.
142 * @since 1.8
143 */
144 RELEASE_8,
145
146 /**
147 * The version recognized by the Java Platform, Standard Edition
148 * 9.
149 *
150 * Additions in this release include modules and removal of a
151 * single underscore from the set of legal identifier names.
152 *
153 * @since 9
154 */
155 RELEASE_9,
156
157 /**
158 * The version recognized by the Java Platform, Standard Edition
159 * 10.
160 *
161 * Additions in this release include local-variable type inference
162 * ({@code var}).
163 *
164 * @since 10
165 */
166 RELEASE_10,
167
168 /**
169 * The version recognized by the Java Platform, Standard Edition
170 * 11.
171 *
172 * @since 11
173 */
174 RELEASE_11,
175
176 /**
177 * The version recognized by the Java Platform, Standard Edition
178 * 12.
179 *
180 * @since 12
181 */
182 RELEASE_12;
183
184 // Note that when adding constants for newer releases, the
185 // behavior of latest() and latestSupported() must be updated too.
186
187 /**
188 * Returns the latest source version that can be modeled.
189 *
190 * @return the latest source version that can be modeled
191 */
192 public static SourceVersion latest() {
193 return RELEASE_12;
194 }
195
196 private static final SourceVersion latestSupported = getLatestSupported();
197
198 private static SourceVersion getLatestSupported() {
199 try {
200 String specVersion = System.getProperty("java.specification.version");
201
202 switch (specVersion) {
203 case "12":
204 return RELEASE_12;
205 case "11":
206 return RELEASE_11;
207 case "10":
208 return RELEASE_10;
209 case "9":
210 return RELEASE_9;
211 case "1.8":
212 return RELEASE_8;
213 case "1.7":
214 return RELEASE_7;
215 case "1.6":
216 return RELEASE_6;
217 }
218 } catch (SecurityException se) {}
219
220 return RELEASE_5;
221 }
222
223 /**
224 * Returns the latest source version fully supported by the
225 * current execution environment. {@code RELEASE_5} or later must
226 * be returned.
227 *
228 * @return the latest source version that is fully supported
229 */
230 public static SourceVersion latestSupported() {
231 return latestSupported;
232 }
233
234 /**
235 * Returns whether or not {@code name} is a syntactically valid
236 * identifier (simple name) or keyword in the latest source
237 * version. The method returns {@code true} if the name consists
238 * of an initial character for which {@link
239 * Character#isJavaIdentifierStart(int)} returns {@code true},
240 * followed only by characters for which {@link
241 * Character#isJavaIdentifierPart(int)} returns {@code true}.
242 * This pattern matches regular identifiers, keywords, restricted
243 * keywords, and the literals {@code "true"}, {@code "false"},
244 * {@code "null"}, and {@code "var"}.
245 *
246 * The method returns {@code false} for all other strings.
247 *
248 * @param name the string to check
249 * @return {@code true} if this string is a
250 * syntactically valid identifier or keyword, {@code false}
251 * otherwise.
252 */
253 public static boolean isIdentifier(CharSequence name) {
254 String id = name.toString();
255
256 if (id.length() == 0) {
257 return false;
258 }
259 int cp = id.codePointAt(0);
260 if (!Character.isJavaIdentifierStart(cp)) {
261 return false;
262 }
263 for (int i = Character.charCount(cp);
264 i < id.length();
265 i += Character.charCount(cp)) {
266 cp = id.codePointAt(i);
267 if (!Character.isJavaIdentifierPart(cp)) {
268 return false;
269 }
270 }
271 return true;
272 }
273
274 /**
275 * Returns whether or not {@code name} is a syntactically valid
276 * qualified name in the latest source version. Unlike {@link
277 * #isIdentifier isIdentifier}, this method returns {@code false}
278 * for keywords, boolean literals, and the null literal.
279 *
280 * This method returns {@code true} for <i>restricted
281 * keywords</i> and {@code "var"}.
282 *
283 * @param name the string to check
284 * @return {@code true} if this string is a
285 * syntactically valid name, {@code false} otherwise.
286 * @jls 3.9 Keywords
287 * @jls 6.2 Names and Identifiers
288 */
289 public static boolean isName(CharSequence name) {
290 return isName(name, latest());
291 }
292
293 /**
294 * Returns whether or not {@code name} is a syntactically valid
295 * qualified name in the given source version. Unlike {@link
296 * #isIdentifier isIdentifier}, this method returns {@code false}
297 * for keywords, boolean literals, and the null literal.
298 *
299 * This method returns {@code true} for <i>restricted
300 * keywords</i> and {@code "var"}.
301 *
302 * @param name the string to check
303 * @param version the version to use
304 * @return {@code true} if this string is a
305 * syntactically valid name, {@code false} otherwise.
306 * @jls 3.9 Keywords
307 * @jls 6.2 Names and Identifiers
308 * @since 9
309 */
310 public static boolean isName(CharSequence name, SourceVersion version) {
311 String id = name.toString();
312
313 for(String s : id.split("\\.", -1)) {
314 if (!isIdentifier(s) || isKeyword(s, version))
315 return false;
316 }
317 return true;
318 }
319
320 /**
321 * Returns whether or not {@code s} is a keyword, boolean literal,
322 * or null literal in the latest source version.
323 * This method returns {@code false} for <i>restricted
324 * keywords</i> and {@code "var"}.
325 *
326 * @param s the string to check
327 * @return {@code true} if {@code s} is a keyword, or boolean
328 * literal, or null literal, {@code false} otherwise.
329 * @jls 3.9 Keywords
330 * @jls 3.10.3 Boolean Literals
331 * @jls 3.10.7 The Null Literal
332 */
333 public static boolean isKeyword(CharSequence s) {
334 return isKeyword(s, latest());
335 }
336
337 /**
338 * Returns whether or not {@code s} is a keyword, boolean literal,
339 * or null literal in the given source version.
340 * This method returns {@code false} for <i>restricted
341 * keywords</i> and {@code "var"}.
342 *
343 * @param s the string to check
344 * @param version the version to use
345 * @return {@code true} if {@code s} is a keyword, or boolean
346 * literal, or null literal, {@code false} otherwise.
347 * @jls 3.9 Keywords
348 * @jls 3.10.3 Boolean Literals
349 * @jls 3.10.7 The Null Literal
350 * @since 9
351 */
352 public static boolean isKeyword(CharSequence s, SourceVersion version) {
353 String id = s.toString();
354 switch(id) {
355 // A trip through history
356 case "strictfp":
357 return version.compareTo(RELEASE_2) >= 0;
358
359 case "assert":
360 return version.compareTo(RELEASE_4) >= 0;
361
362 case "enum":
363 return version.compareTo(RELEASE_5) >= 0;
364
365 case "_":
366 return version.compareTo(RELEASE_9) >= 0;
367
368 // Keywords common across versions
369
370 // Modifiers
371 case "public": case "protected": case "private":
372 case "abstract": case "static": case "final":
373 case "transient": case "volatile": case "synchronized":
374 case "native":
375
376 // Declarations
377 case "class": case "interface": case "extends":
378 case "package": case "throws": case "implements":
379
380 // Primitive types and void
381 case "boolean": case "byte": case "char":
382 case "short": case "int": case "long":
383 case "float": case "double":
384 case "void":
385
386 // Control flow
387 case "if": case "else":
388 case "try": case "catch": case "finally":
389 case "do": case "while":
390 case "for": case "continue":
391 case "switch": case "case": case "default":
392 case "break": case "throw": case "return":
393
394 // Other keywords
395 case "this": case "new": case "super":
396 case "import": case "instanceof":
397
398 // Forbidden!
399 case "goto": case "const":
400
401 // literals
402 case "null": case "true": case "false":
403 return true;
404
405 default:
406 return false;
407 }
408 }
409 }