1 /*
2 * Copyright (c) 1996, 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
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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
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24 */
25
26 package java.lang.reflect;
27
28 import java.util.StringJoiner;
29
30 /**
31 * The Modifier class provides {@code static} methods and
32 * constants to decode class and member access modifiers. The sets of
33 * modifiers are represented as integers with distinct bit positions
34 * representing different modifiers. The values for the constants
35 * representing the modifiers are taken from the tables in sections 4.1, 4.4, 4.5, and 4.7 of
36 * <cite>The Java™ Virtual Machine Specification</cite>.
37 *
38 * @see Class#getModifiers()
39 * @see Member#getModifiers()
40 *
41 * @author Nakul Saraiya
42 * @author Kenneth Russell
43 * @since 1.1
44 */
45 public class Modifier {
46 /**
47 * Return {@code true} if the integer argument includes the
48 * {@code public} modifier, {@code false} otherwise.
49 *
50 * @param mod a set of modifiers
51 * @return {@code true} if {@code mod} includes the
52 * {@code public} modifier; {@code false} otherwise.
53 */
54 public static boolean isPublic(int mod) {
55 return (mod & PUBLIC) != 0;
56 }
57
58 /**
59 * Return {@code true} if the integer argument includes the
60 * {@code private} modifier, {@code false} otherwise.
61 *
62 * @param mod a set of modifiers
63 * @return {@code true} if {@code mod} includes the
64 * {@code private} modifier; {@code false} otherwise.
65 */
66 public static boolean isPrivate(int mod) {
67 return (mod & PRIVATE) != 0;
68 }
69
70 /**
71 * Return {@code true} if the integer argument includes the
72 * {@code protected} modifier, {@code false} otherwise.
73 *
74 * @param mod a set of modifiers
75 * @return {@code true} if {@code mod} includes the
76 * {@code protected} modifier; {@code false} otherwise.
77 */
78 public static boolean isProtected(int mod) {
79 return (mod & PROTECTED) != 0;
80 }
81
82 /**
83 * Return {@code true} if the integer argument includes the
84 * {@code static} modifier, {@code false} otherwise.
85 *
86 * @param mod a set of modifiers
87 * @return {@code true} if {@code mod} includes the
88 * {@code static} modifier; {@code false} otherwise.
89 */
90 public static boolean isStatic(int mod) {
91 return (mod & STATIC) != 0;
92 }
93
94 /**
95 * Return {@code true} if the integer argument includes the
96 * {@code final} modifier, {@code false} otherwise.
97 *
98 * @param mod a set of modifiers
99 * @return {@code true} if {@code mod} includes the
100 * {@code final} modifier; {@code false} otherwise.
101 */
102 public static boolean isFinal(int mod) {
103 return (mod & FINAL) != 0;
104 }
105
106 /**
107 * Return {@code true} if the integer argument includes the
108 * {@code synchronized} modifier, {@code false} otherwise.
109 *
110 * @param mod a set of modifiers
111 * @return {@code true} if {@code mod} includes the
112 * {@code synchronized} modifier; {@code false} otherwise.
113 */
114 public static boolean isSynchronized(int mod) {
115 return (mod & SYNCHRONIZED) != 0;
116 }
117
118 /**
119 * Return {@code true} if the integer argument includes the
120 * {@code volatile} modifier, {@code false} otherwise.
121 *
122 * @param mod a set of modifiers
123 * @return {@code true} if {@code mod} includes the
124 * {@code volatile} modifier; {@code false} otherwise.
125 */
126 public static boolean isVolatile(int mod) {
127 return (mod & VOLATILE) != 0;
128 }
129
130 /**
131 * Return {@code true} if the integer argument includes the
132 * {@code transient} modifier, {@code false} otherwise.
133 *
134 * @param mod a set of modifiers
135 * @return {@code true} if {@code mod} includes the
136 * {@code transient} modifier; {@code false} otherwise.
137 */
138 public static boolean isTransient(int mod) {
139 return (mod & TRANSIENT) != 0;
140 }
141
142 /**
143 * Return {@code true} if the integer argument includes the
144 * {@code native} modifier, {@code false} otherwise.
145 *
146 * @param mod a set of modifiers
147 * @return {@code true} if {@code mod} includes the
148 * {@code native} modifier; {@code false} otherwise.
149 */
150 public static boolean isNative(int mod) {
151 return (mod & NATIVE) != 0;
152 }
153
154 /**
155 * Return {@code true} if the integer argument includes the
156 * {@code interface} modifier, {@code false} otherwise.
157 *
158 * @param mod a set of modifiers
159 * @return {@code true} if {@code mod} includes the
160 * {@code interface} modifier; {@code false} otherwise.
161 */
162 public static boolean isInterface(int mod) {
163 return (mod & INTERFACE) != 0;
164 }
165
166 /**
167 * Return {@code true} if the integer argument includes the
168 * {@code abstract} modifier, {@code false} otherwise.
169 *
170 * @param mod a set of modifiers
171 * @return {@code true} if {@code mod} includes the
172 * {@code abstract} modifier; {@code false} otherwise.
173 */
174 public static boolean isAbstract(int mod) {
175 return (mod & ABSTRACT) != 0;
176 }
177
178 /**
179 * Return {@code true} if the integer argument includes the
180 * {@code strictfp} modifier, {@code false} otherwise.
181 *
182 * @param mod a set of modifiers
183 * @return {@code true} if {@code mod} includes the
184 * {@code strictfp} modifier; {@code false} otherwise.
185 */
186 public static boolean isStrict(int mod) {
187 return (mod & STRICT) != 0;
188 }
189
190 /**
191 * Return a string describing the access modifier flags in
192 * the specified modifier. For example:
193 * <blockquote><pre>
194 * public final synchronized strictfp
195 * </pre></blockquote>
196 * The modifier names are returned in an order consistent with the
197 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
198 * <cite>The Java™ Language Specification</cite>.
199 * The full modifier ordering used by this method is:
200 * <blockquote> {@code
201 * public protected private abstract static final transient
202 * volatile synchronized native strictfp
203 * interface } </blockquote>
204 * The {@code interface} modifier discussed in this class is
205 * not a true modifier in the Java language and it appears after
206 * all other modifiers listed by this method. This method may
207 * return a string of modifiers that are not valid modifiers of a
208 * Java entity; in other words, no checking is done on the
209 * possible validity of the combination of modifiers represented
210 * by the input.
211 *
212 * Note that to perform such checking for a known kind of entity,
213 * such as a constructor or method, first AND the argument of
214 * {@code toString} with the appropriate mask from a method like
215 * {@link #constructorModifiers} or {@link #methodModifiers}.
216 *
217 * @param mod a set of modifiers
218 * @return a string representation of the set of modifiers
219 * represented by {@code mod}
220 */
221 public static String toString(int mod) {
222 StringJoiner sj = new StringJoiner(" ");
223
224 if ((mod & PUBLIC) != 0) sj.add("public");
225 if ((mod & PROTECTED) != 0) sj.add("protected");
226 if ((mod & PRIVATE) != 0) sj.add("private");
227
228 /* Canonical order */
229 if ((mod & ABSTRACT) != 0) sj.add("abstract");
230 if ((mod & STATIC) != 0) sj.add("static");
231 if ((mod & FINAL) != 0) sj.add("final");
232 if ((mod & TRANSIENT) != 0) sj.add("transient");
233 if ((mod & VOLATILE) != 0) sj.add("volatile");
234 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
235 if ((mod & NATIVE) != 0) sj.add("native");
236 if ((mod & STRICT) != 0) sj.add("strictfp");
237 if ((mod & INTERFACE) != 0) sj.add("interface");
238
239 return sj.toString();
240 }
241
242 /*
243 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
244 * <cite>The Java™ Virtual Machine Specification</cite>
245 */
246
247 /**
248 * The {@code int} value representing the {@code public}
249 * modifier.
250 */
251 public static final int PUBLIC = 0x00000001;
252
253 /**
254 * The {@code int} value representing the {@code private}
255 * modifier.
256 */
257 public static final int PRIVATE = 0x00000002;
258
259 /**
260 * The {@code int} value representing the {@code protected}
261 * modifier.
262 */
263 public static final int PROTECTED = 0x00000004;
264
265 /**
266 * The {@code int} value representing the {@code static}
267 * modifier.
268 */
269 public static final int STATIC = 0x00000008;
270
271 /**
272 * The {@code int} value representing the {@code final}
273 * modifier.
274 */
275 public static final int FINAL = 0x00000010;
276
277 /**
278 * The {@code int} value representing the {@code synchronized}
279 * modifier.
280 */
281 public static final int SYNCHRONIZED = 0x00000020;
282
283 /**
284 * The {@code int} value representing the {@code volatile}
285 * modifier.
286 */
287 public static final int VOLATILE = 0x00000040;
288
289 /**
290 * The {@code int} value representing the {@code transient}
291 * modifier.
292 */
293 public static final int TRANSIENT = 0x00000080;
294
295 /**
296 * The {@code int} value representing the {@code native}
297 * modifier.
298 */
299 public static final int NATIVE = 0x00000100;
300
301 /**
302 * The {@code int} value representing the {@code interface}
303 * modifier.
304 */
305 public static final int INTERFACE = 0x00000200;
306
307 /**
308 * The {@code int} value representing the {@code abstract}
309 * modifier.
310 */
311 public static final int ABSTRACT = 0x00000400;
312
313 /**
314 * The {@code int} value representing the {@code strictfp}
315 * modifier.
316 */
317 public static final int STRICT = 0x00000800;
318
319 // Bits not (yet) exposed in the public API either because they
320 // have different meanings for fields and methods and there is no
321 // way to distinguish between the two in this class, or because
322 // they are not Java programming language keywords
323 static final int BRIDGE = 0x00000040;
324 static final int VARARGS = 0x00000080;
325 static final int SYNTHETIC = 0x00001000;
326 static final int ANNOTATION = 0x00002000;
327 static final int ENUM = 0x00004000;
328 static final int MANDATED = 0x00008000;
329 static boolean isSynthetic(int mod) {
330 return (mod & SYNTHETIC) != 0;
331 }
332
333 static boolean isMandated(int mod) {
334 return (mod & MANDATED) != 0;
335 }
336
337 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
338 // the sets of modifiers are not guaranteed to be constants
339 // across time and Java SE releases. Therefore, it would not be
340 // appropriate to expose an external interface to this information
341 // that would allow the values to be treated as Java-level
342 // constants since the values could be constant folded and updates
343 // to the sets of modifiers missed. Thus, the fooModifiers()
344 // methods return an unchanging values for a given release, but a
345 // value that can potentially change over time.
346
347 /**
348 * The Java source modifiers that can be applied to a class.
349 * @jls 8.1.1 Class Modifiers
350 */
351 private static final int CLASS_MODIFIERS =
352 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
353 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
354 Modifier.STRICT;
355
356 /**
357 * The Java source modifiers that can be applied to an interface.
358 * @jls 9.1.1 Interface Modifiers
359 */
360 private static final int INTERFACE_MODIFIERS =
361 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
362 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
363
364
365 /**
366 * The Java source modifiers that can be applied to a constructor.
367 * @jls 8.8.3 Constructor Modifiers
368 */
369 private static final int CONSTRUCTOR_MODIFIERS =
370 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
371
372 /**
373 * The Java source modifiers that can be applied to a method.
374 * @jls8.4.3 Method Modifiers
375 */
376 private static final int METHOD_MODIFIERS =
377 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
378 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
379 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
380
381 /**
382 * The Java source modifiers that can be applied to a field.
383 * @jls 8.3.1 Field Modifiers
384 */
385 private static final int FIELD_MODIFIERS =
386 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
387 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
388 Modifier.VOLATILE;
389
390 /**
391 * The Java source modifiers that can be applied to a method or constructor parameter.
392 * @jls 8.4.1 Formal Parameters
393 */
394 private static final int PARAMETER_MODIFIERS =
395 Modifier.FINAL;
396
397 /**
398 *
399 */
400 static final int ACCESS_MODIFIERS =
401 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
402
403 /**
404 * Return an {@code int} value OR-ing together the source language
405 * modifiers that can be applied to a class.
406 * @return an {@code int} value OR-ing together the source language
407 * modifiers that can be applied to a class.
408 *
409 * @jls 8.1.1 Class Modifiers
410 * @since 1.7
411 */
412 public static int classModifiers() {
413 return CLASS_MODIFIERS;
414 }
415
416 /**
417 * Return an {@code int} value OR-ing together the source language
418 * modifiers that can be applied to an interface.
419 * @return an {@code int} value OR-ing together the source language
420 * modifiers that can be applied to an interface.
421 *
422 * @jls 9.1.1 Interface Modifiers
423 * @since 1.7
424 */
425 public static int interfaceModifiers() {
426 return INTERFACE_MODIFIERS;
427 }
428
429 /**
430 * Return an {@code int} value OR-ing together the source language
431 * modifiers that can be applied to a constructor.
432 * @return an {@code int} value OR-ing together the source language
433 * modifiers that can be applied to a constructor.
434 *
435 * @jls 8.8.3 Constructor Modifiers
436 * @since 1.7
437 */
438 public static int constructorModifiers() {
439 return CONSTRUCTOR_MODIFIERS;
440 }
441
442 /**
443 * Return an {@code int} value OR-ing together the source language
444 * modifiers that can be applied to a method.
445 * @return an {@code int} value OR-ing together the source language
446 * modifiers that can be applied to a method.
447 *
448 * @jls 8.4.3 Method Modifiers
449 * @since 1.7
450 */
451 public static int methodModifiers() {
452 return METHOD_MODIFIERS;
453 }
454
455 /**
456 * Return an {@code int} value OR-ing together the source language
457 * modifiers that can be applied to a field.
458 * @return an {@code int} value OR-ing together the source language
459 * modifiers that can be applied to a field.
460 *
461 * @jls 8.3.1 Field Modifiers
462 * @since 1.7
463 */
464 public static int fieldModifiers() {
465 return FIELD_MODIFIERS;
466 }
467
468 /**
469 * Return an {@code int} value OR-ing together the source language
470 * modifiers that can be applied to a parameter.
471 * @return an {@code int} value OR-ing together the source language
472 * modifiers that can be applied to a parameter.
473 *
474 * @jls 8.4.1 Formal Parameters
475 * @since 1.8
476 */
477 public static int parameterModifiers() {
478 return PARAMETER_MODIFIERS;
479 }
480 }