1 /*
2 * Copyright (c) 2005, 2016, 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 */
60
61 /**
62 * The original version.
63 *
64 * The language described in
65 * <cite>The Java™ Language Specification, First Edition</cite>.
66 */
67 RELEASE_0,
68
69 /**
70 * The version recognized by the Java Platform 1.1.
71 *
72 * The language is {@code RELEASE_0} augmented with nested classes as described in the 1.1 update to
73 * <cite>The Java™ Language Specification, First Edition</cite>.
74 */
75 RELEASE_1,
76
77 /**
78 * The version recognized by the Java 2 Platform, Standard Edition,
79 * v 1.2.
80 *
81 * The language described in
82 * <cite>The Java™ Language Specification,
83 * Second Edition</cite>, which includes the {@code
84 * strictfp} modifier.
85 */
86 RELEASE_2,
87
88 /**
89 * The version recognized by the Java 2 Platform, Standard Edition,
90 * v 1.3.
91 *
92 * No major changes from {@code RELEASE_2}.
93 */
94 RELEASE_3,
95
96 /**
97 * The version recognized by the Java 2 Platform, Standard Edition,
98 * v 1.4.
99 *
100 * Added a simple assertion facility.
101 */
102 RELEASE_4,
103
104 /**
105 * The version recognized by the Java 2 Platform, Standard
106 * Edition 5.0.
107 *
108 * The language described in
109 * <cite>The Java™ Language Specification,
110 * Third Edition</cite>. First release to support
111 * generics, annotations, autoboxing, var-args, enhanced {@code
112 * for} loop, and hexadecimal floating-point literals.
113 */
114 RELEASE_5,
115
116 /**
117 * The version recognized by the Java Platform, Standard Edition
118 * 6.
119 *
120 * No major changes from {@code RELEASE_5}.
121 */
122 RELEASE_6,
123
124 /**
125 * The version recognized by the Java Platform, Standard Edition
126 * 7.
127 *
128 * Additions in this release include, diamond syntax for
129 * constructors, {@code try}-with-resources, strings in switch,
130 * binary literals, and multi-catch.
131 * @since 1.7
132 */
133 RELEASE_7,
134
135 /**
136 * The version recognized by the Java Platform, Standard Edition
137 * 8.
138 *
139 * Additions in this release include lambda expressions and default methods.
140 * @since 1.8
141 */
142 RELEASE_8,
143
144 /**
145 * The version recognized by the Java Platform, Standard Edition
146 * 9.
147 *
148 * Additions in this release include modules and removal of a
149 * single underscore from the set of legal identifier names.
150 *
151 * @since 9
152 */
153 RELEASE_9;
154
155 // Note that when adding constants for newer releases, the
156 // behavior of latest() and latestSupported() must be updated too.
157
158 /**
159 * Returns the latest source version that can be modeled.
160 *
161 * @return the latest source version that can be modeled
162 */
163 public static SourceVersion latest() {
164 return RELEASE_9;
165 }
166
167 private static final SourceVersion latestSupported = getLatestSupported();
168
169 private static SourceVersion getLatestSupported() {
170 try {
171 String specVersion = System.getProperty("java.specification.version");
172
173 switch (specVersion) {
174 case "9":
175 case "1.9":
176 return RELEASE_9;
177 case "1.8":
178 return RELEASE_8;
179 case "1.7":
180 return RELEASE_7;
181 case "1.6":
182 return RELEASE_6;
183 }
184 } catch (SecurityException se) {}
185
186 return RELEASE_5;
187 }
188
189 /**
190 * Returns the latest source version fully supported by the
191 * current execution environment. {@code RELEASE_5} or later must
192 * be returned.
193 *
194 * @return the latest source version that is fully supported
195 */
196 public static SourceVersion latestSupported() {
197 return latestSupported;
198 }
199
200 /**
201 * Returns whether or not {@code name} is a syntactically valid
202 * identifier (simple name) or keyword in the latest source
203 * version. The method returns {@code true} if the name consists
204 * of an initial character for which {@link
205 * Character#isJavaIdentifierStart(int)} returns {@code true},
206 * followed only by characters for which {@link
207 * Character#isJavaIdentifierPart(int)} returns {@code true}.
208 * This pattern matches regular identifiers, keywords, and the
209 * literals {@code "true"}, {@code "false"}, and {@code "null"}.
210 * The method returns {@code false} for all other strings.
211 *
212 * @param name the string to check
213 * @return {@code true} if this string is a
214 * syntactically valid identifier or keyword, {@code false}
215 * otherwise.
216 */
217 public static boolean isIdentifier(CharSequence name) {
218 String id = name.toString();
219
220 if (id.length() == 0) {
221 return false;
222 }
223 int cp = id.codePointAt(0);
224 if (!Character.isJavaIdentifierStart(cp)) {
225 return false;
226 }
227 for (int i = Character.charCount(cp);
228 i < id.length();
229 i += Character.charCount(cp)) {
230 cp = id.codePointAt(i);
231 if (!Character.isJavaIdentifierPart(cp)) {
232 return false;
233 }
234 }
235 return true;
236 }
237
238 /**
239 * Returns whether or not {@code name} is a syntactically valid
240 * qualified name in the latest source version. Unlike {@link
241 * #isIdentifier isIdentifier}, this method returns {@code false}
242 * for keywords and literals.
243 *
244 * @param name the string to check
245 * @return {@code true} if this string is a
246 * syntactically valid name, {@code false} otherwise.
247 * @jls 6.2 Names and Identifiers
248 */
249 public static boolean isName(CharSequence name) {
250 return isName(name, latest());
251 }
252
253 /**
254 * Returns whether or not {@code name} is a syntactically valid
255 * qualified name in the given source version. Unlike {@link
256 * #isIdentifier isIdentifier}, this method returns {@code false}
257 * for keywords and literals.
258 *
259 * @param name the string to check
260 * @param version the version to use
261 * @return {@code true} if this string is a
262 * syntactically valid name, {@code false} otherwise.
263 * @jls 6.2 Names and Identifiers
264 * @since 9
265 */
266 public static boolean isName(CharSequence name, SourceVersion version) {
267 String id = name.toString();
268
269 for(String s : id.split("\\.", -1)) {
270 if (!isIdentifier(s) || isKeyword(s, version))
271 return false;
272 }
273 return true;
274 }
275
276 /**
277 * Returns whether or not {@code s} is a keyword or literal in the
278 * latest source version.
279 *
280 * @param s the string to check
281 * @return {@code true} if {@code s} is a keyword or literal, {@code false} otherwise.
282 */
283 public static boolean isKeyword(CharSequence s) {
284 return isKeyword(s, latest());
285 }
286
287 /**
288 * Returns whether or not {@code s} is a keyword or literal in the
289 * given source version.
290 *
291 * @param s the string to check
292 * @param version the version to use
293 * @return {@code true} if {@code s} is a keyword or literal, {@code false} otherwise.
294 * @since 9
295 */
296 public static boolean isKeyword(CharSequence s, SourceVersion version) {
297 String id = s.toString();
298 switch(id) {
299 // A trip through history
300 case "strictfp":
301 return version.compareTo(RELEASE_2) >= 0;
302
303 case "assert":
304 return version.compareTo(RELEASE_4) >= 0;
305
306 case "enum":
307 return version.compareTo(RELEASE_5) >= 0;
308
309 case "_":
310 return version.compareTo(RELEASE_9) >= 0;
311
312 // Keywords common across versions
313 case "abstract": case "continue": case "for": case "new":
314 case "switch": case "default": case "if": case "package":
315 case "synchronized": case "boolean": case "do": case "goto":
316 case "private": case "this": case "break": case "double":
317 case "implements": case "protected": case "throw": case "byte":
318 case "else": case "import": case "public": case "throws":
319 case "case": case "instanceof": case "return": case "transient":
320 case "catch": case "extends": case "int": case "short":
321 case "try": case "char": case "final": case "interface":
322 case "static": case "void": case "class": case "finally":
323 case "long": case "volatile": case "const": case "float":
324 case "native": case "super": case "while":
325 // literals
326 case "null": case "true": case "false":
327 return true;
328
329 default:
330 return false;
331 }
332 }
333 }