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: to-be-determined changes
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 * @since 10
161 */
162 RELEASE_10;
163
164 // Note that when adding constants for newer releases, the
165 // behavior of latest() and latestSupported() must be updated too.
166
167 /**
168 * Returns the latest source version that can be modeled.
169 *
170 * @return the latest source version that can be modeled
171 */
172 public static SourceVersion latest() {
173 return RELEASE_10;
174 }
175
176 private static final SourceVersion latestSupported = getLatestSupported();
177
178 private static SourceVersion getLatestSupported() {
179 try {
180 String specVersion = System.getProperty("java.specification.version");
181
182 switch (specVersion) {
183 case "10":
184 return RELEASE_10;
185 case "9":
186 case "1.9":
187 return RELEASE_9;
188 case "1.8":
189 return RELEASE_8;
190 case "1.7":
191 return RELEASE_7;
192 case "1.6":
193 return RELEASE_6;
194 }
195 } catch (SecurityException se) {}
196
197 return RELEASE_5;
198 }
199
200 /**
201 * Returns the latest source version fully supported by the
202 * current execution environment. {@code RELEASE_5} or later must
203 * be returned.
204 *
205 * @return the latest source version that is fully supported
206 */
207 public static SourceVersion latestSupported() {
208 return latestSupported;
209 }
210
211 /**
212 * Returns whether or not {@code name} is a syntactically valid
213 * identifier (simple name) or keyword in the latest source
214 * version. The method returns {@code true} if the name consists
215 * of an initial character for which {@link
216 * Character#isJavaIdentifierStart(int)} returns {@code true},
217 * followed only by characters for which {@link
218 * Character#isJavaIdentifierPart(int)} returns {@code true}.
219 * This pattern matches regular identifiers, keywords, restricted
220 * keywords, and the literals {@code "true"}, {@code "false"}, and
221 * {@code "null"}.
222 * The method returns {@code false} for all other strings.
223 *
224 * @param name the string to check
225 * @return {@code true} if this string is a
226 * syntactically valid identifier or keyword, {@code false}
227 * otherwise.
228 */
229 public static boolean isIdentifier(CharSequence name) {
230 String id = name.toString();
231
232 if (id.length() == 0) {
233 return false;
234 }
235 int cp = id.codePointAt(0);
236 if (!Character.isJavaIdentifierStart(cp)) {
237 return false;
238 }
239 for (int i = Character.charCount(cp);
240 i < id.length();
241 i += Character.charCount(cp)) {
242 cp = id.codePointAt(i);
243 if (!Character.isJavaIdentifierPart(cp)) {
244 return false;
245 }
246 }
247 return true;
248 }
249
250 /**
251 * Returns whether or not {@code name} is a syntactically valid
252 * qualified name in the latest source version. Unlike {@link
253 * #isIdentifier isIdentifier}, this method returns {@code false}
254 * for keywords, boolean literals, and the null literal.
255 * This method returns {@code true} for <i>restricted
256 * keywords</i>.
257 *
258 * @param name the string to check
259 * @return {@code true} if this string is a
260 * syntactically valid name, {@code false} otherwise.
261 * @jls 3.9 Keywords
262 * @jls 6.2 Names and Identifiers
263 */
264 public static boolean isName(CharSequence name) {
265 return isName(name, latest());
266 }
267
268 /**
269 * Returns whether or not {@code name} is a syntactically valid
270 * qualified name in the given source version. Unlike {@link
271 * #isIdentifier isIdentifier}, this method returns {@code false}
272 * for keywords, boolean literals, and the null literal.
273 * This method returns {@code true} for <i>restricted
274 * keywords</i>.
275 *
276 * @param name the string to check
277 * @param version the version to use
278 * @return {@code true} if this string is a
279 * syntactically valid name, {@code false} otherwise.
280 * @jls 3.9 Keywords
281 * @jls 6.2 Names and Identifiers
282 * @since 9
283 */
284 public static boolean isName(CharSequence name, SourceVersion version) {
285 String id = name.toString();
286
287 for(String s : id.split("\\.", -1)) {
288 if (!isIdentifier(s) || isKeyword(s, version))
289 return false;
290 }
291 return true;
292 }
293
294 /**
295 * Returns whether or not {@code s} is a keyword, boolean literal,
296 * or null literal in the latest source version.
297 * This method returns {@code false} for <i>restricted
298 * keywords</i>.
299 *
300 * @param s the string to check
301 * @return {@code true} if {@code s} is a keyword, or boolean
302 * literal, or null literal, {@code false} otherwise.
303 * @jls 3.9 Keywords
304 * @jls 3.10.3 Boolean Literals
305 * @jls 3.10.7 The Null Literal
306 */
307 public static boolean isKeyword(CharSequence s) {
308 return isKeyword(s, latest());
309 }
310
311 /**
312 * Returns whether or not {@code s} is a keyword, boolean literal,
313 * or null literal in the given source version.
314 * This method returns {@code false} for <i>restricted
315 * keywords</i>.
316 *
317 * @param s the string to check
318 * @param version the version to use
319 * @return {@code true} if {@code s} is a keyword, or boolean
320 * literal, or null literal, {@code false} otherwise.
321 * @jls 3.9 Keywords
322 * @jls 3.10.3 Boolean Literals
323 * @jls 3.10.7 The Null Literal
324 * @since 9
325 */
326 public static boolean isKeyword(CharSequence s, SourceVersion version) {
327 String id = s.toString();
328 switch(id) {
329 // A trip through history
330 case "strictfp":
331 return version.compareTo(RELEASE_2) >= 0;
332
333 case "assert":
334 return version.compareTo(RELEASE_4) >= 0;
335
336 case "enum":
337 return version.compareTo(RELEASE_5) >= 0;
338
339 case "_":
340 return version.compareTo(RELEASE_9) >= 0;
341
342 // Keywords common across versions
343
344 // Modifiers
345 case "public": case "protected": case "private":
346 case "abstract": case "static": case "final":
347 case "transient": case "volatile": case "synchronized":
348 case "native":
349
350 // Declarations
351 case "class": case "interface": case "extends":
352 case "package": case "throws": case "implements":
353
354 // Primitive types and void
355 case "boolean": case "byte": case "char":
356 case "short": case "int": case "long":
357 case "float": case "double":
358 case "void":
359
360 // Control flow
361 case "if": case "else":
362 case "try": case "catch": case "finally":
363 case "do": case "while":
364 case "for": case "continue":
365 case "switch": case "case": case "default":
366 case "break": case "throw": case "return":
367
368 // Other keywords
369 case "this": case "new": case "super":
370 case "import": case "instanceof":
371
372 // Forbidden!
373 case "goto": case "const":
374
375 // literals
376 case "null": case "true": case "false":
377 return true;
378
379 default:
380 return false;
381 }
382 }
383 }