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 * 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 * 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 * @since 11
176 */
177 RELEASE_11;
178
179 // Note that when adding constants for newer releases, the
180 // behavior of latest() and latestSupported() must be updated too.
181
182 /**
183 * Returns the latest source version that can be modeled.
184 *
185 * @return the latest source version that can be modeled
186 */
187 public static SourceVersion latest() {
188 return RELEASE_11;
189 }
190
191 private static final SourceVersion latestSupported = getLatestSupported();
192
193 private static SourceVersion getLatestSupported() {
194 try {
195 String specVersion = System.getProperty("java.specification.version");
196
197 switch (specVersion) {
198 case "11":
199 return RELEASE_11;
200 case "10":
201 return RELEASE_10;
202 case "9":
203 return RELEASE_9;
204 case "1.8":
205 return RELEASE_8;
206 case "1.7":
207 return RELEASE_7;
208 case "1.6":
209 return RELEASE_6;
210 }
211 } catch (SecurityException se) {}
212
213 return RELEASE_5;
214 }
215
216 /**
217 * Returns the latest source version fully supported by the
218 * current execution environment. {@code RELEASE_5} or later must
219 * be returned.
220 *
221 * @return the latest source version that is fully supported
222 */
223 public static SourceVersion latestSupported() {
224 return latestSupported;
225 }
226
227 /**
228 * Returns whether or not {@code name} is a syntactically valid
229 * identifier (simple name) or keyword in the latest source
230 * version. The method returns {@code true} if the name consists
231 * of an initial character for which {@link
232 * Character#isJavaIdentifierStart(int)} returns {@code true},
233 * followed only by characters for which {@link
234 * Character#isJavaIdentifierPart(int)} returns {@code true}.
235 * This pattern matches regular identifiers, keywords, restricted
236 * keywords, and the literals {@code "true"}, {@code "false"}, and
237 * {@code "null"}.
238 * The method returns {@code false} for all other strings.
239 *
240 * @param name the string to check
241 * @return {@code true} if this string is a
242 * syntactically valid identifier or keyword, {@code false}
243 * otherwise.
244 */
245 public static boolean isIdentifier(CharSequence name) {
246 String id = name.toString();
247
248 if (id.length() == 0) {
249 return false;
250 }
251 int cp = id.codePointAt(0);
252 if (!Character.isJavaIdentifierStart(cp)) {
253 return false;
254 }
255 for (int i = Character.charCount(cp);
256 i < id.length();
257 i += Character.charCount(cp)) {
258 cp = id.codePointAt(i);
259 if (!Character.isJavaIdentifierPart(cp)) {
260 return false;
261 }
262 }
263 return true;
264 }
265
266 /**
267 * Returns whether or not {@code name} is a syntactically valid
268 * qualified name in the latest source version. Unlike {@link
269 * #isIdentifier isIdentifier}, this method returns {@code false}
270 * for keywords, boolean literals, and the null literal.
271 * This method returns {@code true} for <i>restricted
272 * keywords</i>.
273 *
274 * @param name the string to check
275 * @return {@code true} if this string is a
276 * syntactically valid name, {@code false} otherwise.
277 * @jls 3.9 Keywords
278 * @jls 6.2 Names and Identifiers
279 */
280 public static boolean isName(CharSequence name) {
281 return isName(name, latest());
282 }
283
284 /**
285 * Returns whether or not {@code name} is a syntactically valid
286 * qualified name in the given source version. Unlike {@link
287 * #isIdentifier isIdentifier}, this method returns {@code false}
288 * for keywords, boolean literals, and the null literal.
289 * This method returns {@code true} for <i>restricted
290 * keywords</i>.
291 *
292 * @param name the string to check
293 * @param version the version to use
294 * @return {@code true} if this string is a
295 * syntactically valid name, {@code false} otherwise.
296 * @jls 3.9 Keywords
297 * @jls 6.2 Names and Identifiers
298 * @since 9
299 */
300 public static boolean isName(CharSequence name, SourceVersion version) {
301 String id = name.toString();
302
303 for(String s : id.split("\\.", -1)) {
304 if (!isIdentifier(s) || isKeyword(s, version))
305 return false;
306 }
307 return true;
308 }
309
310 /**
311 * Returns whether or not {@code s} is a keyword, boolean literal,
312 * or null literal in the latest source version.
313 * This method returns {@code false} for <i>restricted
314 * keywords</i>.
315 *
316 * @param s the string to check
317 * @return {@code true} if {@code s} is a keyword, or boolean
318 * literal, or null literal, {@code false} otherwise.
319 * @jls 3.9 Keywords
320 * @jls 3.10.3 Boolean Literals
321 * @jls 3.10.7 The Null Literal
322 */
323 public static boolean isKeyword(CharSequence s) {
324 return isKeyword(s, latest());
325 }
326
327 /**
328 * Returns whether or not {@code s} is a keyword, boolean literal,
329 * or null literal in the given source version.
330 * This method returns {@code false} for <i>restricted
331 * keywords</i>.
332 *
333 * @param s the string to check
334 * @param version the version to use
335 * @return {@code true} if {@code s} is a keyword, or boolean
336 * literal, or null literal, {@code false} otherwise.
337 * @jls 3.9 Keywords
338 * @jls 3.10.3 Boolean Literals
339 * @jls 3.10.7 The Null Literal
340 * @since 9
341 */
342 public static boolean isKeyword(CharSequence s, SourceVersion version) {
343 String id = s.toString();
344 switch(id) {
345 // A trip through history
346 case "strictfp":
347 return version.compareTo(RELEASE_2) >= 0;
348
349 case "assert":
350 return version.compareTo(RELEASE_4) >= 0;
351
352 case "enum":
353 return version.compareTo(RELEASE_5) >= 0;
354
355 case "_":
356 return version.compareTo(RELEASE_9) >= 0;
357
358 // Keywords common across versions
359
360 // Modifiers
361 case "public": case "protected": case "private":
362 case "abstract": case "static": case "final":
363 case "transient": case "volatile": case "synchronized":
364 case "native":
365
366 // Declarations
367 case "class": case "interface": case "extends":
368 case "package": case "throws": case "implements":
369
370 // Primitive types and void
371 case "boolean": case "byte": case "char":
372 case "short": case "int": case "long":
373 case "float": case "double":
374 case "void":
375
376 // Control flow
377 case "if": case "else":
378 case "try": case "catch": case "finally":
379 case "do": case "while":
380 case "for": case "continue":
381 case "switch": case "case": case "default":
382 case "break": case "throw": case "return":
383
384 // Other keywords
385 case "this": case "new": case "super":
386 case "import": case "instanceof":
387
388 // Forbidden!
389 case "goto": case "const":
390
391 // literals
392 case "null": case "true": case "false":
393 return true;
394
395 default:
396 return false;
397 }
398 }
399 }