1 /*
2 * Copyright (c) 1996, 2024, 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
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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 *
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23 * questions.
24 */
25
26 package java.lang.reflect;
27
28 import jdk.internal.javac.PreviewFeature;
29
30 import java.util.StringJoiner;
31
32 /**
33 * The Modifier class provides {@code static} methods and
34 * constants to decode class and member access modifiers.
35 * The {@link AccessFlag} class should be used instead of this class.
36 * The sets of modifiers are represented as integers with non-distinct bit positions
37 * representing different modifiers. The values for the constants
38 * representing the modifiers are taken from the tables in sections
39 * {@jvms 4.1}, {@jvms 4.4}, {@jvms 4.5}, and {@jvms 4.7} of
40 * <cite>The Java Virtual Machine Specification</cite>.
41 *
42 * @see Class#accessFlags()
43 * @see Member#accessFlags()
44 * @see Class#getModifiers()
45 * @see Member#getModifiers()
46 *
47 * @author Nakul Saraiya
48 * @author Kenneth Russell
49 * @since 1.1
50 */
51 public class Modifier {
52 /**
53 * Do not call.
54 */
55 private Modifier() {throw new AssertionError();}
56
57
58 /**
59 * Return {@code true} if the integer argument includes the
60 * {@code public} modifier, {@code false} otherwise.
61 *
62 * @param mod a set of modifiers
63 * @return {@code true} if {@code mod} includes the
64 * {@code public} modifier; {@code false} otherwise.
65 */
66 public static boolean isPublic(int mod) {
67 return (mod & PUBLIC) != 0;
68 }
69
70 /**
71 * Return {@code true} if the integer argument includes the
72 * {@code private} modifier, {@code false} otherwise.
73 *
74 * @param mod a set of modifiers
75 * @return {@code true} if {@code mod} includes the
76 * {@code private} modifier; {@code false} otherwise.
77 */
78 public static boolean isPrivate(int mod) {
79 return (mod & PRIVATE) != 0;
80 }
81
82 /**
83 * Return {@code true} if the integer argument includes the
84 * {@code protected} modifier, {@code false} otherwise.
85 *
86 * @param mod a set of modifiers
87 * @return {@code true} if {@code mod} includes the
88 * {@code protected} modifier; {@code false} otherwise.
89 */
90 public static boolean isProtected(int mod) {
91 return (mod & PROTECTED) != 0;
92 }
93
94 /**
95 * Return {@code true} if the integer argument includes the
96 * {@code static} modifier, {@code false} otherwise.
97 *
98 * @param mod a set of modifiers
99 * @return {@code true} if {@code mod} includes the
100 * {@code static} modifier; {@code false} otherwise.
101 */
102 public static boolean isStatic(int mod) {
103 return (mod & STATIC) != 0;
104 }
105
106 /**
107 * Return {@code true} if the integer argument includes the
108 * {@code final} modifier, {@code false} otherwise.
109 *
110 * @param mod a set of modifiers
111 * @return {@code true} if {@code mod} includes the
112 * {@code final} modifier; {@code false} otherwise.
113 */
114 public static boolean isFinal(int mod) {
115 return (mod & FINAL) != 0;
116 }
117
118 /**
119 * Return {@code true} if the integer argument includes the
120 * {@code synchronized} modifier, {@code false} otherwise.
121 *
122 * @apiNote {@code isSynchronized} should only be called with the modifiers
123 * of a {@linkplain Method#getModifiers() method}.
124 *
125 * @param mod a set of modifiers
126 * @return {@code true} if {@code mod} includes the
127 * {@code synchronized} modifier; {@code false} otherwise.
128 */
129 public static boolean isSynchronized(int mod) {
130 return (mod & SYNCHRONIZED) != 0;
131 }
132
133 /**
134 * Return {@code true} if the integer argument includes the
135 * {@code identity} modifier, {@code false} otherwise.
136 *
137 * @apiNote {@code isIdentity} should only be called with the modifiers
138 * of a {@linkplain Class#getModifiers() class}.
139 *
140 * @param mod a set of modifiers
141 * @return {@code true} if {@code mod} includes the
142 * {@code identity} modifier; {@code false} otherwise.
143 */
144 public static boolean isIdentity(int mod) {
145 return (mod & IDENTITY) != 0;
146 }
147
148 /**
149 * Return {@code true} if the integer argument includes the
150 * {@code volatile} modifier, {@code false} otherwise.
151 *
152 * @param mod a set of modifiers
153 * @return {@code true} if {@code mod} includes the
154 * {@code volatile} modifier; {@code false} otherwise.
155 */
156 public static boolean isVolatile(int mod) {
157 return (mod & VOLATILE) != 0;
158 }
159
160 /**
161 * Return {@code true} if the integer argument includes the
162 * {@code transient} modifier, {@code false} otherwise.
163 *
164 * @param mod a set of modifiers
165 * @return {@code true} if {@code mod} includes the
166 * {@code transient} modifier; {@code false} otherwise.
167 */
168 public static boolean isTransient(int mod) {
169 return (mod & TRANSIENT) != 0;
170 }
171
172 /**
173 * Return {@code true} if the integer argument includes the
174 * {@code native} modifier, {@code false} otherwise.
175 *
176 * @param mod a set of modifiers
177 * @return {@code true} if {@code mod} includes the
178 * {@code native} modifier; {@code false} otherwise.
179 */
180 public static boolean isNative(int mod) {
181 return (mod & NATIVE) != 0;
182 }
183
184 /**
185 * Return {@code true} if the integer argument includes the
186 * {@code interface} modifier, {@code false} otherwise.
187 *
188 * @param mod a set of modifiers
189 * @return {@code true} if {@code mod} includes the
190 * {@code interface} modifier; {@code false} otherwise.
191 */
192 public static boolean isInterface(int mod) {
193 return (mod & INTERFACE) != 0;
194 }
195
196 /**
197 * Return {@code true} if the integer argument includes the
198 * {@code abstract} modifier, {@code false} otherwise.
199 *
200 * @param mod a set of modifiers
201 * @return {@code true} if {@code mod} includes the
202 * {@code abstract} modifier; {@code false} otherwise.
203 */
204 public static boolean isAbstract(int mod) {
205 return (mod & ABSTRACT) != 0;
206 }
207
208 /**
209 * Return {@code true} if the integer argument includes the
210 * {@code strictfp} modifier, {@code false} otherwise.
211 *
212 * @param mod a set of modifiers
213 * @return {@code true} if {@code mod} includes the
214 * {@code strictfp} modifier; {@code false} otherwise.
215 */
216 public static boolean isStrict(int mod) {
217 return (mod & STRICT) != 0;
218 }
219
220 /**
221 * Return a string describing the access modifier flags in
222 * the specified modifier. For example:
223 * <blockquote><pre>
224 * public final synchronized strictfp
225 * </pre></blockquote>
226 * The modifier names are returned in an order consistent with the
227 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
228 * <cite>The Java Language Specification</cite>.
229 * The full modifier ordering used by this method is:
230 * <blockquote> {@code
231 * public protected private abstract static final transient
232 * volatile synchronized native strictfp
233 * interface } </blockquote>
234 * The {@code interface} modifier discussed in this class is
235 * not a true modifier in the Java language and it appears after
236 * all other modifiers listed by this method. This method may
237 * return a string of modifiers that are not valid modifiers of a
238 * Java entity; in other words, no checking is done on the
239 * possible validity of the combination of modifiers represented
240 * by the input.
241 *
242 * Note that to perform such checking for a known kind of entity,
243 * such as a constructor or method, first AND the argument of
244 * {@code toString} with the appropriate mask from a method like
245 * {@link #constructorModifiers} or {@link #methodModifiers}.
246 *
247 * @param mod a set of modifiers
248 * @return a string representation of the set of modifiers
249 * represented by {@code mod}
250 */
251 public static String toString(int mod) {
252 StringJoiner sj = new StringJoiner(" ");
253
254 if ((mod & PUBLIC) != 0) sj.add("public");
255 if ((mod & PROTECTED) != 0) sj.add("protected");
256 if ((mod & PRIVATE) != 0) sj.add("private");
257
258 /* Canonical order */
259 if ((mod & ABSTRACT) != 0) sj.add("abstract");
260 if ((mod & STATIC) != 0) sj.add("static");
261 if ((mod & FINAL) != 0) sj.add("final");
262 if ((mod & TRANSIENT) != 0) sj.add("transient");
263 if ((mod & VOLATILE) != 0) sj.add("volatile");
264 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
265 if ((mod & NATIVE) != 0) sj.add("native");
266 if ((mod & STRICT) != 0) sj.add("strictfp");
267 if ((mod & INTERFACE) != 0) sj.add("interface");
268
269 return sj.toString();
270 }
271
272 /*
273 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
274 * <cite>The Java Virtual Machine Specification</cite>
275 */
276
277 /**
278 * The {@code int} value representing the {@code public}
279 * modifier.
280 * @see AccessFlag#PUBLIC
281 */
282 public static final int PUBLIC = 0x00000001;
283
284 /**
285 * The {@code int} value representing the {@code private}
286 * modifier.
287 * @see AccessFlag#PRIVATE
288 */
289 public static final int PRIVATE = 0x00000002;
290
291 /**
292 * The {@code int} value representing the {@code protected}
293 * modifier.
294 * @see AccessFlag#PROTECTED
295 */
296 public static final int PROTECTED = 0x00000004;
297
298 /**
299 * The {@code int} value representing the {@code static}
300 * modifier.
301 * @see AccessFlag#STATIC
302 */
303 public static final int STATIC = 0x00000008;
304
305 /**
306 * The {@code int} value representing the {@code final}
307 * modifier.
308 * @see AccessFlag#FINAL
309 */
310 public static final int FINAL = 0x00000010;
311
312 /**
313 * The {@code int} value representing the {@code synchronized}
314 * modifier.
315 * @see AccessFlag#SYNCHRONIZED
316 */
317 public static final int SYNCHRONIZED = 0x00000020;
318
319 /**
320 * The {@code int} value representing the {@code ACC_IDENTITY}
321 * modifier.
322 */
323 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS)
324 public static final int IDENTITY = 0x00000020;
325
326 /**
327 * The {@code int} value representing the {@code volatile}
328 * modifier.
329 * @see AccessFlag#VOLATILE
330 */
331 public static final int VOLATILE = 0x00000040;
332
333 /**
334 * The {@code int} value representing the {@code transient}
335 * modifier.
336 * @see AccessFlag#TRANSIENT
337 */
338 public static final int TRANSIENT = 0x00000080;
339
340 /**
341 * The {@code int} value representing the {@code native}
342 * modifier.
343 * @see AccessFlag#NATIVE
344 */
345 public static final int NATIVE = 0x00000100;
346
347 /**
348 * The {@code int} value representing the {@code interface}
349 * modifier.
350 * @see AccessFlag#INTERFACE
351 */
352 public static final int INTERFACE = 0x00000200;
353
354 /**
355 * The {@code int} value representing the {@code abstract}
356 * modifier.
357 * @see AccessFlag#ABSTRACT
358 */
359 public static final int ABSTRACT = 0x00000400;
360
361 /**
362 * The {@code int} value representing the {@code strictfp}
363 * modifier.
364 * @see AccessFlag#STRICT
365 */
366 public static final int STRICT = 0x00000800;
367
368 // Bits not (yet) exposed in the public API either because they
369 // have different meanings for fields and methods and there is no
370 // way to distinguish between the two in this class, or because
371 // they are not Java programming language keywords
372 static final int BRIDGE = 0x00000040;
373 static final int VARARGS = 0x00000080;
374 static final int SYNTHETIC = 0x00001000;
375 static final int ANNOTATION = 0x00002000;
376 static final int ENUM = 0x00004000;
377 static final int MANDATED = 0x00008000;
378 static boolean isSynthetic(int mod) {
379 return (mod & SYNTHETIC) != 0;
380 }
381
382 static boolean isMandated(int mod) {
383 return (mod & MANDATED) != 0;
384 }
385
386 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
387 // the sets of modifiers are not guaranteed to be constants
388 // across time and Java SE releases. Therefore, it would not be
389 // appropriate to expose an external interface to this information
390 // that would allow the values to be treated as Java-level
391 // constants since the values could be constant folded and updates
392 // to the sets of modifiers missed. Thus, the fooModifiers()
393 // methods return an unchanging values for a given release, but a
394 // value that can potentially change over time.
395
396 /**
397 * The Java source modifiers that can be applied to a class.
398 * @jls 8.1.1 Class Modifiers
399 */
400 private static final int CLASS_MODIFIERS =
401 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
402 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
403 Modifier.IDENTITY | Modifier.STRICT;
404
405 /**
406 * The Java source modifiers that can be applied to an interface.
407 * @jls 9.1.1 Interface Modifiers
408 */
409 private static final int INTERFACE_MODIFIERS =
410 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
411 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
412
413
414 /**
415 * The Java source modifiers that can be applied to a constructor.
416 * @jls 8.8.3 Constructor Modifiers
417 */
418 private static final int CONSTRUCTOR_MODIFIERS =
419 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
420
421 /**
422 * The Java source modifiers that can be applied to a method.
423 * @jls 8.4.3 Method Modifiers
424 */
425 private static final int METHOD_MODIFIERS =
426 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
427 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
428 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
429
430 /**
431 * The Java source modifiers that can be applied to a field.
432 * @jls 8.3.1 Field Modifiers
433 */
434 private static final int FIELD_MODIFIERS =
435 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
436 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
437 Modifier.VOLATILE;
438
439 /**
440 * The Java source modifiers that can be applied to a method or constructor parameter.
441 * @jls 8.4.1 Formal Parameters
442 */
443 private static final int PARAMETER_MODIFIERS =
444 Modifier.FINAL;
445
446 static final int ACCESS_MODIFIERS =
447 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
448
449 /**
450 * Return an {@code int} value OR-ing together the source language
451 * modifiers that can be applied to a class.
452 * @return an {@code int} value OR-ing together the source language
453 * modifiers that can be applied to a class.
454 *
455 * @jls 8.1.1 Class Modifiers
456 * @since 1.7
457 */
458 public static int classModifiers() {
459 return CLASS_MODIFIERS;
460 }
461
462 /**
463 * Return an {@code int} value OR-ing together the source language
464 * modifiers that can be applied to an interface.
465 * @return an {@code int} value OR-ing together the source language
466 * modifiers that can be applied to an interface.
467 *
468 * @jls 9.1.1 Interface Modifiers
469 * @since 1.7
470 */
471 public static int interfaceModifiers() {
472 return INTERFACE_MODIFIERS;
473 }
474
475 /**
476 * Return an {@code int} value OR-ing together the source language
477 * modifiers that can be applied to a constructor.
478 * @return an {@code int} value OR-ing together the source language
479 * modifiers that can be applied to a constructor.
480 *
481 * @jls 8.8.3 Constructor Modifiers
482 * @since 1.7
483 */
484 public static int constructorModifiers() {
485 return CONSTRUCTOR_MODIFIERS;
486 }
487
488 /**
489 * Return an {@code int} value OR-ing together the source language
490 * modifiers that can be applied to a method.
491 * @return an {@code int} value OR-ing together the source language
492 * modifiers that can be applied to a method.
493 *
494 * @jls 8.4.3 Method Modifiers
495 * @since 1.7
496 */
497 public static int methodModifiers() {
498 return METHOD_MODIFIERS;
499 }
500
501 /**
502 * Return an {@code int} value OR-ing together the source language
503 * modifiers that can be applied to a field.
504 * @return an {@code int} value OR-ing together the source language
505 * modifiers that can be applied to a field.
506 *
507 * @jls 8.3.1 Field Modifiers
508 * @since 1.7
509 */
510 public static int fieldModifiers() {
511 return FIELD_MODIFIERS;
512 }
513
514 /**
515 * Return an {@code int} value OR-ing together the source language
516 * modifiers that can be applied to a parameter.
517 * @return an {@code int} value OR-ing together the source language
518 * modifiers that can be applied to a parameter.
519 *
520 * @jls 8.4.1 Formal Parameters
521 * @since 1.8
522 */
523 public static int parameterModifiers() {
524 return PARAMETER_MODIFIERS;
525 }
526 }