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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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 * @apiNote
43 * Not all modifiers that are syntactic Java language modifiers are
44 * represented in this class, only those modifiers that <em>also</em>
45 * have a corresponding JVM {@linkplain AccessFlag access flag} are
46 * included. In particular, the {@code default} method modifier (JLS
47 * {@jls 9.4.3}) and the {@code value}, {@code sealed} and {@code non-sealed} class
48 * (JLS {@jls 8.1.1.2}) and interface (JLS {@jls 9.1.1.4}) modifiers
49 * are <em>not</em> represented in this class.
50 *
51 * @see Class#getModifiers()
52 * @see Member#getModifiers()
53 *
54 * @author Nakul Saraiya
55 * @author Kenneth Russell
56 * @since 1.1
57 */
58 public class Modifier {
59 /**
60 * Do not call.
61 */
62 private Modifier() {throw new AssertionError();}
63
64
65 /**
66 * Return {@code true} if the integer argument includes the
67 * {@code public} modifier, {@code false} otherwise.
68 *
69 * @param mod a set of modifiers
70 * @return {@code true} if {@code mod} includes the
71 * {@code public} modifier; {@code false} otherwise.
72 */
73 public static boolean isPublic(int mod) {
74 return (mod & PUBLIC) != 0;
75 }
76
77 /**
78 * Return {@code true} if the integer argument includes the
79 * {@code private} modifier, {@code false} otherwise.
80 *
81 * @param mod a set of modifiers
82 * @return {@code true} if {@code mod} includes the
83 * {@code private} modifier; {@code false} otherwise.
84 */
85 public static boolean isPrivate(int mod) {
86 return (mod & PRIVATE) != 0;
87 }
88
89 /**
90 * Return {@code true} if the integer argument includes the
91 * {@code protected} modifier, {@code false} otherwise.
92 *
93 * @param mod a set of modifiers
94 * @return {@code true} if {@code mod} includes the
95 * {@code protected} modifier; {@code false} otherwise.
96 */
97 public static boolean isProtected(int mod) {
98 return (mod & PROTECTED) != 0;
99 }
100
101 /**
102 * Return {@code true} if the integer argument includes the
103 * {@code static} modifier, {@code false} otherwise.
104 *
105 * @param mod a set of modifiers
106 * @return {@code true} if {@code mod} includes the
107 * {@code static} modifier; {@code false} otherwise.
108 */
109 public static boolean isStatic(int mod) {
110 return (mod & STATIC) != 0;
111 }
112
113 /**
114 * Return {@code true} if the integer argument includes the
115 * {@code final} modifier, {@code false} otherwise.
116 *
117 * @param mod a set of modifiers
118 * @return {@code true} if {@code mod} includes the
119 * {@code final} modifier; {@code false} otherwise.
120 */
121 public static boolean isFinal(int mod) {
122 return (mod & FINAL) != 0;
123 }
124
125 /**
126 * Return {@code true} if the integer argument includes the
127 * {@code synchronized} modifier, {@code false} otherwise.
128 *
129 * @apiNote {@code isSynchronized} should only be called with the modifiers
130 * of a {@linkplain Method#getModifiers() method}.
131 *
132 * @param mod a set of modifiers
133 * @return {@code true} if {@code mod} includes the
134 * {@code synchronized} modifier; {@code false} otherwise.
135 */
136 public static boolean isSynchronized(int mod) {
137 return (mod & SYNCHRONIZED) != 0;
138 }
139
140 /**
141 * Return {@code true} if the integer argument includes the
142 * {@code identity} modifier, {@code false} otherwise.
143 *
144 * @apiNote {@code isIdentity} should only be called with the modifiers
145 * of a {@linkplain Class#getModifiers() class}.
146 *
147 * @param mod a set of modifiers
148 * @return {@code true} if {@code mod} includes the
149 * {@code identity} modifier; {@code false} otherwise.
150 *
151 * @since Valhalla
152 */
153 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
154 public static boolean isIdentity(int mod) {
155 return (mod & IDENTITY) != 0;
156 }
157
158 /**
159 * Return {@code true} if the integer argument includes the
160 * {@code volatile} modifier, {@code false} otherwise.
161 *
162 * @param mod a set of modifiers
163 * @return {@code true} if {@code mod} includes the
164 * {@code volatile} modifier; {@code false} otherwise.
165 */
166 public static boolean isVolatile(int mod) {
167 return (mod & VOLATILE) != 0;
168 }
169
170 /**
171 * Return {@code true} if the integer argument includes the
172 * {@code transient} modifier, {@code false} otherwise.
173 *
174 * @param mod a set of modifiers
175 * @return {@code true} if {@code mod} includes the
176 * {@code transient} modifier; {@code false} otherwise.
177 */
178 public static boolean isTransient(int mod) {
179 return (mod & TRANSIENT) != 0;
180 }
181
182 /**
183 * Return {@code true} if the integer argument includes the
184 * {@code native} modifier, {@code false} otherwise.
185 *
186 * @param mod a set of modifiers
187 * @return {@code true} if {@code mod} includes the
188 * {@code native} modifier; {@code false} otherwise.
189 */
190 public static boolean isNative(int mod) {
191 return (mod & NATIVE) != 0;
192 }
193
194 /**
195 * Return {@code true} if the integer argument includes the
196 * {@code interface} modifier, {@code false} otherwise.
197 *
198 * @param mod a set of modifiers
199 * @return {@code true} if {@code mod} includes the
200 * {@code interface} modifier; {@code false} otherwise.
201 */
202 public static boolean isInterface(int mod) {
203 return (mod & INTERFACE) != 0;
204 }
205
206 /**
207 * Return {@code true} if the integer argument includes the
208 * {@code abstract} modifier, {@code false} otherwise.
209 *
210 * @param mod a set of modifiers
211 * @return {@code true} if {@code mod} includes the
212 * {@code abstract} modifier; {@code false} otherwise.
213 */
214 public static boolean isAbstract(int mod) {
215 return (mod & ABSTRACT) != 0;
216 }
217
218 /**
219 * Return {@code true} if the integer argument includes the
220 * {@code strictfp} modifier, {@code false} otherwise.
221 *
222 * @param mod a set of modifiers
223 * @return {@code true} if {@code mod} includes the
224 * {@code strictfp} modifier; {@code false} otherwise.
225 */
226 public static boolean isStrict(int mod) {
227 return (mod & STRICT) != 0;
228 }
229
230 /**
231 * Return a string describing the access modifier flags in
232 * the specified modifier. For example:
233 * <blockquote><pre>
234 * public final synchronized
235 * </pre></blockquote>
236 * The modifier names are returned in an order consistent with the
237 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
238 * <cite>The Java Language Specification</cite>.
239 * The full modifier ordering used by this method is:
240 * <blockquote> {@code
241 * public protected private abstract static final transient
242 * volatile synchronized native strictfp
243 * interface } </blockquote>
244 *
245 * The {@code interface} modifier discussed in this class is
246 * not a true modifier in the Java language and it appears after
247 * all other modifiers listed by this method. This method may
248 * return a string of modifiers that are not valid modifiers of a
249 * Java entity; in other words, no checking is done on the
250 * possible validity of the combination of modifiers represented
251 * by the input.
252 *
253 * Note that to perform such checking for a known kind of entity,
254 * such as a constructor or method, first AND the argument of
255 * {@code toString} with the appropriate mask from a method like
256 * {@link #constructorModifiers} or {@link #methodModifiers}.
257 *
258 * @apiNote
259 * To make a high-fidelity representation of the Java source
260 * modifiers of a class or member, source-level modifiers that do
261 * <em>not</em> have a constant in this class should be included
262 * and appear in an order consistent with the full recommended
263 * ordering for that kind of declaration as given in <cite>The
264 * Java Language Specification</cite>. For example, for a
265 * {@linkplain Method#toGenericString() method} the "{@link
266 * Method#isDefault() default}" modifier is ordered immediately
267 * before "{@code static}" (JLS {@jls 9.4}). For a {@linkplain
268 * Class#toGenericString() class object}, the "{@link
269 * Class#isSealed() sealed}" or {@code "non-sealed"} modifier is
270 * ordered immediately after "{@code final}" for a class (JLS
271 * {@jls 8.1.1}) and immediately after "{@code static}" for an
272 * interface (JLS {@jls 9.1.1}).
273 *
274 * @param mod a set of modifiers
275 * @return a string representation of the set of modifiers
276 * represented by {@code mod}
277 */
278 public static String toString(int mod) {
279 StringJoiner sj = new StringJoiner(" ");
280
281 if ((mod & PUBLIC) != 0) sj.add("public");
282 if ((mod & PROTECTED) != 0) sj.add("protected");
283 if ((mod & PRIVATE) != 0) sj.add("private");
284
285 /* Canonical order */
286 if ((mod & ABSTRACT) != 0) sj.add("abstract");
287 if ((mod & STATIC) != 0) sj.add("static");
288 if ((mod & FINAL) != 0) sj.add("final");
289 if ((mod & TRANSIENT) != 0) sj.add("transient");
290 if ((mod & VOLATILE) != 0) sj.add("volatile");
291 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
292 if ((mod & NATIVE) != 0) sj.add("native");
293 if ((mod & STRICT) != 0) sj.add("strictfp");
294 if ((mod & INTERFACE) != 0) sj.add("interface");
295
296 return sj.toString();
297 }
298
299 /*
300 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
301 * <cite>The Java Virtual Machine Specification</cite>
302 */
303
304 /**
305 * The {@code int} value representing the {@code public}
306 * modifier.
307 * @see AccessFlag#PUBLIC
308 */
309 public static final int PUBLIC = 0x00000001;
310
311 /**
312 * The {@code int} value representing the {@code private}
313 * modifier.
314 * @see AccessFlag#PRIVATE
315 */
316 public static final int PRIVATE = 0x00000002;
317
318 /**
319 * The {@code int} value representing the {@code protected}
320 * modifier.
321 * @see AccessFlag#PROTECTED
322 */
323 public static final int PROTECTED = 0x00000004;
324
325 /**
326 * The {@code int} value representing the {@code static}
327 * modifier.
328 * @see AccessFlag#STATIC
329 */
330 public static final int STATIC = 0x00000008;
331
332 /**
333 * The {@code int} value representing the {@code final}
334 * modifier.
335 * @see AccessFlag#FINAL
336 */
337 public static final int FINAL = 0x00000010;
338
339 /**
340 * The {@code int} value representing the {@code synchronized}
341 * modifier.
342 * @see AccessFlag#SYNCHRONIZED
343 */
344 public static final int SYNCHRONIZED = 0x00000020;
345
346 /**
347 * The {@code int} value representing the {@code ACC_IDENTITY}
348 * modifier.
349 *
350 * @since Valhalla
351 */
352 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
353 public static final int IDENTITY = 0x00000020;
354
355 /**
356 * The {@code int} value representing the {@code volatile}
357 * modifier.
358 * @see AccessFlag#VOLATILE
359 */
360 public static final int VOLATILE = 0x00000040;
361
362 /**
363 * The {@code int} value representing the {@code transient}
364 * modifier.
365 * @see AccessFlag#TRANSIENT
366 */
367 public static final int TRANSIENT = 0x00000080;
368
369 /**
370 * The {@code int} value representing the {@code native}
371 * modifier.
372 * @see AccessFlag#NATIVE
373 */
374 public static final int NATIVE = 0x00000100;
375
376 /**
377 * The {@code int} value representing the {@code interface}
378 * modifier.
379 * @see AccessFlag#INTERFACE
380 */
381 public static final int INTERFACE = 0x00000200;
382
383 /**
384 * The {@code int} value representing the {@code abstract}
385 * modifier.
386 * @see AccessFlag#ABSTRACT
387 */
388 public static final int ABSTRACT = 0x00000400;
389
390 /**
391 * The {@code int} value representing the {@code strictfp}
392 * modifier.
393 * @see AccessFlag#STRICT and AccessFlag#STRICT_FIELD
394 */
395 public static final int STRICT = 0x00000800;
396
397 // Bits not (yet) exposed in the public API either because they
398 // have different meanings for fields and methods and there is no
399 // way to distinguish between the two in this class, or because
400 // they are not Java programming language keywords
401 static final int BRIDGE = 0x00000040;
402 static final int VARARGS = 0x00000080;
403 static final int SYNTHETIC = 0x00001000;
404 static final int ANNOTATION = 0x00002000;
405 static final int ENUM = 0x00004000;
406 static final int MANDATED = 0x00008000;
407 static boolean isSynthetic(int mod) {
408 return (mod & SYNTHETIC) != 0;
409 }
410
411 static boolean isMandated(int mod) {
412 return (mod & MANDATED) != 0;
413 }
414
415 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
416 // the sets of modifiers are not guaranteed to be constants
417 // across time and Java SE releases. Therefore, it would not be
418 // appropriate to expose an external interface to this information
419 // that would allow the values to be treated as Java-level
420 // constants since the values could be constant folded and updates
421 // to the sets of modifiers missed. Thus, the fooModifiers()
422 // methods return an unchanging values for a given release, but a
423 // value that can potentially change over time.
424
425 /**
426 * The Java source modifiers that can be applied to a class.
427 * @jls 8.1.1 Class Modifiers
428 */
429 private static final int CLASS_MODIFIERS =
430 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
431 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
432 Modifier.IDENTITY | Modifier.STRICT;
433
434 /**
435 * The Java source modifiers that can be applied to an interface.
436 * @jls 9.1.1 Interface Modifiers
437 */
438 private static final int INTERFACE_MODIFIERS =
439 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
440 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
441
442
443 /**
444 * The Java source modifiers that can be applied to a constructor.
445 * @jls 8.8.3 Constructor Modifiers
446 */
447 private static final int CONSTRUCTOR_MODIFIERS =
448 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
449
450 /**
451 * The Java source modifiers that can be applied to a method.
452 * @jls 8.4.3 Method Modifiers
453 */
454 private static final int METHOD_MODIFIERS =
455 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
456 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
457 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
458
459 /**
460 * The Java source modifiers that can be applied to a field.
461 * @jls 8.3.1 Field Modifiers
462 */
463 private static final int FIELD_MODIFIERS =
464 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
465 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
466 Modifier.VOLATILE | Modifier.STRICT;
467
468 /**
469 * The Java source modifiers that can be applied to a method or constructor parameter.
470 * @jls 8.4.1 Formal Parameters
471 */
472 private static final int PARAMETER_MODIFIERS =
473 Modifier.FINAL;
474
475 static final int ACCESS_MODIFIERS =
476 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
477
478 /**
479 * Return an {@code int} value OR-ing together the source language
480 * modifiers that can be applied to a class.
481 * @return an {@code int} value OR-ing together the source language
482 * modifiers that can be applied to a class.
483 *
484 * @jls 8.1.1 Class Modifiers
485 * @since 1.7
486 */
487 public static int classModifiers() {
488 return CLASS_MODIFIERS;
489 }
490
491 /**
492 * Return an {@code int} value OR-ing together the source language
493 * modifiers that can be applied to an interface.
494 * @return an {@code int} value OR-ing together the source language
495 * modifiers that can be applied to an interface.
496 *
497 * @jls 9.1.1 Interface Modifiers
498 * @since 1.7
499 */
500 public static int interfaceModifiers() {
501 return INTERFACE_MODIFIERS;
502 }
503
504 /**
505 * Return an {@code int} value OR-ing together the source language
506 * modifiers that can be applied to a constructor.
507 * @return an {@code int} value OR-ing together the source language
508 * modifiers that can be applied to a constructor.
509 *
510 * @jls 8.8.3 Constructor Modifiers
511 * @since 1.7
512 */
513 public static int constructorModifiers() {
514 return CONSTRUCTOR_MODIFIERS;
515 }
516
517 /**
518 * Return an {@code int} value OR-ing together the source language
519 * modifiers that can be applied to a method.
520 * @return an {@code int} value OR-ing together the source language
521 * modifiers that can be applied to a method.
522 *
523 * @jls 8.4.3 Method Modifiers
524 * @since 1.7
525 */
526 public static int methodModifiers() {
527 return METHOD_MODIFIERS;
528 }
529
530 /**
531 * Return an {@code int} value OR-ing together the source language
532 * modifiers that can be applied to a field.
533 * @return an {@code int} value OR-ing together the source language
534 * modifiers that can be applied to a field.
535 *
536 * @jls 8.3.1 Field Modifiers
537 * @since 1.7
538 */
539 public static int fieldModifiers() {
540 return FIELD_MODIFIERS;
541 }
542
543 /**
544 * Return an {@code int} value OR-ing together the source language
545 * modifiers that can be applied to a parameter.
546 * @return an {@code int} value OR-ing together the source language
547 * modifiers that can be applied to a parameter.
548 *
549 * @jls 8.4.1 Formal Parameters
550 * @since 1.8
551 */
552 public static int parameterModifiers() {
553 return PARAMETER_MODIFIERS;
554 }
555 }