1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
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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).
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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
36 * {@jvms 4.1}, {@jvms 4.4}, {@jvms 4.5}, and {@jvms 4.7} of
37 * <cite>The Java Virtual Machine Specification</cite>.
38 *
39 * @apiNote
40 * Not all modifiers that are syntactic Java language modifiers are
41 * represented in this class, only those modifiers that <em>also</em>
42 * have a corresponding JVM {@linkplain AccessFlag access flag} are
43 * included. In particular the {@code default} method modifier (JLS
44 * {@jls 9.4.3}) and the {@code sealed} and {@code non-sealed} class
45 * (JLS {@jls 8.1.1.2}) and interface (JLS {@jls 9.1.1.4}) modifiers
46 * are <em>not</em> represented in this class.
47 *
48 * @see Class#getModifiers()
49 * @see Member#getModifiers()
50 *
51 * @author Nakul Saraiya
52 * @author Kenneth Russell
53 * @since 1.1
54 */
55 public class Modifier {
56 /**
57 * Do not call.
58 */
59 private Modifier() {throw new AssertionError();}
60
61
62 /**
63 * Return {@code true} if the integer argument includes the
64 * {@code public} modifier, {@code false} otherwise.
65 *
66 * @param mod a set of modifiers
67 * @return {@code true} if {@code mod} includes the
68 * {@code public} modifier; {@code false} otherwise.
69 */
70 public static boolean isPublic(int mod) {
71 return (mod & PUBLIC) != 0;
72 }
73
74 /**
75 * Return {@code true} if the integer argument includes the
76 * {@code private} modifier, {@code false} otherwise.
77 *
78 * @param mod a set of modifiers
79 * @return {@code true} if {@code mod} includes the
80 * {@code private} modifier; {@code false} otherwise.
81 */
82 public static boolean isPrivate(int mod) {
83 return (mod & PRIVATE) != 0;
84 }
85
86 /**
87 * Return {@code true} if the integer argument includes the
88 * {@code protected} modifier, {@code false} otherwise.
89 *
90 * @param mod a set of modifiers
91 * @return {@code true} if {@code mod} includes the
92 * {@code protected} modifier; {@code false} otherwise.
93 */
94 public static boolean isProtected(int mod) {
95 return (mod & PROTECTED) != 0;
96 }
97
98 /**
99 * Return {@code true} if the integer argument includes the
100 * {@code static} modifier, {@code false} otherwise.
101 *
102 * @param mod a set of modifiers
103 * @return {@code true} if {@code mod} includes the
104 * {@code static} modifier; {@code false} otherwise.
105 */
106 public static boolean isStatic(int mod) {
107 return (mod & STATIC) != 0;
108 }
109
110 /**
111 * Return {@code true} if the integer argument includes the
112 * {@code final} modifier, {@code false} otherwise.
113 *
114 * @param mod a set of modifiers
115 * @return {@code true} if {@code mod} includes the
116 * {@code final} modifier; {@code false} otherwise.
117 */
118 public static boolean isFinal(int mod) {
119 return (mod & FINAL) != 0;
120 }
121
122 /**
123 * Return {@code true} if the integer argument includes the
124 * {@code synchronized} modifier, {@code false} otherwise.
125 *
126 * @param mod a set of modifiers
127 * @return {@code true} if {@code mod} includes the
128 * {@code synchronized} modifier; {@code false} otherwise.
129 */
130 public static boolean isSynchronized(int mod) {
131 return (mod & SYNCHRONIZED) != 0;
132 }
133
134 /**
135 * Return {@code true} if the integer argument includes the
136 * {@code volatile} modifier, {@code false} otherwise.
137 *
138 * @param mod a set of modifiers
139 * @return {@code true} if {@code mod} includes the
140 * {@code volatile} modifier; {@code false} otherwise.
141 */
142 public static boolean isVolatile(int mod) {
143 return (mod & VOLATILE) != 0;
144 }
145
146 /**
147 * Return {@code true} if the integer argument includes the
148 * {@code transient} modifier, {@code false} otherwise.
149 *
150 * @param mod a set of modifiers
151 * @return {@code true} if {@code mod} includes the
152 * {@code transient} modifier; {@code false} otherwise.
153 */
154 public static boolean isTransient(int mod) {
155 return (mod & TRANSIENT) != 0;
156 }
157
158 /**
159 * Return {@code true} if the integer argument includes the
160 * {@code native} modifier, {@code false} otherwise.
161 *
162 * @param mod a set of modifiers
163 * @return {@code true} if {@code mod} includes the
164 * {@code native} modifier; {@code false} otherwise.
165 */
166 public static boolean isNative(int mod) {
167 return (mod & NATIVE) != 0;
168 }
169
170 /**
171 * Return {@code true} if the integer argument includes the
172 * {@code interface} modifier, {@code false} otherwise.
173 *
174 * @param mod a set of modifiers
175 * @return {@code true} if {@code mod} includes the
176 * {@code interface} modifier; {@code false} otherwise.
177 */
178 public static boolean isInterface(int mod) {
179 return (mod & INTERFACE) != 0;
180 }
181
182 /**
183 * Return {@code true} if the integer argument includes the
184 * {@code abstract} modifier, {@code false} otherwise.
185 *
186 * @param mod a set of modifiers
187 * @return {@code true} if {@code mod} includes the
188 * {@code abstract} modifier; {@code false} otherwise.
189 */
190 public static boolean isAbstract(int mod) {
191 return (mod & ABSTRACT) != 0;
192 }
193
194 /**
195 * Return {@code true} if the integer argument includes the
196 * {@code strictfp} modifier, {@code false} otherwise.
197 *
198 * @param mod a set of modifiers
199 * @return {@code true} if {@code mod} includes the
200 * {@code strictfp} modifier; {@code false} otherwise.
201 */
202 public static boolean isStrict(int mod) {
203 return (mod & STRICT) != 0;
204 }
205
206 /**
207 * Return a string describing the access modifier flags in
208 * the specified modifier. For example:
209 * <blockquote><pre>
210 * public final synchronized strictfp
211 * </pre></blockquote>
212 * The modifier names are returned in an order consistent with the
213 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
214 * <cite>The Java Language Specification</cite>.
215 * The full modifier ordering used by this method is:
216 * <blockquote> {@code
217 * public protected private abstract static final transient
218 * volatile synchronized native strictfp
219 * interface } </blockquote>
220 *
221 * The {@code interface} modifier discussed in this class is
222 * not a true modifier in the Java language and it appears after
223 * all other modifiers listed by this method. This method may
224 * return a string of modifiers that are not valid modifiers of a
225 * Java entity; in other words, no checking is done on the
226 * possible validity of the combination of modifiers represented
227 * by the input.
228 *
229 * Note that to perform such checking for a known kind of entity,
230 * such as a constructor or method, first AND the argument of
231 * {@code toString} with the appropriate mask from a method like
232 * {@link #constructorModifiers} or {@link #methodModifiers}.
233 *
234 * @apiNote
235 * To make a high-fidelity representation of the Java source
236 * modifiers of a class or member, source-level modifiers that do
237 * <em>not</em> have a constant in this class should be included
238 * and appear in an order consistent with the full recommended
239 * ordering for that kind of declaration as given in <cite>The
240 * Java Language Specification</cite>. For example, for a
241 * {@linkplain Method#toGenericString() method} the "{@link
242 * Method#isDefault() default}" modifier is ordered immediately
243 * before "{@code static}" (JLS {@jls 9.4}). For a {@linkplain
244 * Class#toGenericString() class object}, the "{@link
245 * Class#isSealed() sealed}" or {@code "non-sealed"} modifier is
246 * ordered immediately after "{@code final}" for a class (JLS
247 * {@jls 8.1.1}) and immediately after "{@code static}" for an
248 * interface (JLS {@jls 9.1.1}).
249 *
250 * @param mod a set of modifiers
251 * @return a string representation of the set of modifiers
252 * represented by {@code mod}
253 */
254 public static String toString(int mod) {
255 StringJoiner sj = new StringJoiner(" ");
256
257 if ((mod & PUBLIC) != 0) sj.add("public");
258 if ((mod & PROTECTED) != 0) sj.add("protected");
259 if ((mod & PRIVATE) != 0) sj.add("private");
260
261 /* Canonical order */
262 if ((mod & ABSTRACT) != 0) sj.add("abstract");
263 if ((mod & STATIC) != 0) sj.add("static");
264 if ((mod & FINAL) != 0) sj.add("final");
265 if ((mod & TRANSIENT) != 0) sj.add("transient");
266 if ((mod & VOLATILE) != 0) sj.add("volatile");
267 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
268 if ((mod & NATIVE) != 0) sj.add("native");
269 if ((mod & STRICT) != 0) sj.add("strictfp");
270 if ((mod & INTERFACE) != 0) sj.add("interface");
271
272 return sj.toString();
273 }
274
275 /*
276 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
277 * <cite>The Java Virtual Machine Specification</cite>
278 */
279
280 /**
281 * The {@code int} value representing the {@code public}
282 * modifier.
283 * @see AccessFlag#PUBLIC
284 */
285 public static final int PUBLIC = 0x00000001;
286
287 /**
288 * The {@code int} value representing the {@code private}
289 * modifier.
290 * @see AccessFlag#PRIVATE
291 */
292 public static final int PRIVATE = 0x00000002;
293
294 /**
295 * The {@code int} value representing the {@code protected}
296 * modifier.
297 * @see AccessFlag#PROTECTED
298 */
299 public static final int PROTECTED = 0x00000004;
300
301 /**
302 * The {@code int} value representing the {@code static}
303 * modifier.
304 * @see AccessFlag#STATIC
305 */
306 public static final int STATIC = 0x00000008;
307
308 /**
309 * The {@code int} value representing the {@code final}
310 * modifier.
311 * @see AccessFlag#FINAL
312 */
313 public static final int FINAL = 0x00000010;
314
315 /**
316 * The {@code int} value representing the {@code synchronized}
317 * modifier.
318 * @see AccessFlag#SYNCHRONIZED
319 */
320 public static final int SYNCHRONIZED = 0x00000020;
321
322 /**
323 * The {@code int} value representing the {@code volatile}
324 * modifier.
325 * @see AccessFlag#VOLATILE
326 */
327 public static final int VOLATILE = 0x00000040;
328
329 /**
330 * The {@code int} value representing the {@code transient}
331 * modifier.
332 * @see AccessFlag#TRANSIENT
333 */
334 public static final int TRANSIENT = 0x00000080;
335
336 /**
337 * The {@code int} value representing the {@code native}
338 * modifier.
339 * @see AccessFlag#NATIVE
340 */
341 public static final int NATIVE = 0x00000100;
342
343 /**
344 * The {@code int} value representing the {@code interface}
345 * modifier.
346 * @see AccessFlag#INTERFACE
347 */
348 public static final int INTERFACE = 0x00000200;
349
350 /**
351 * The {@code int} value representing the {@code abstract}
352 * modifier.
353 * @see AccessFlag#ABSTRACT
354 */
355 public static final int ABSTRACT = 0x00000400;
356
357 /**
358 * The {@code int} value representing the {@code strictfp}
359 * modifier.
360 * @see AccessFlag#STRICT
361 */
362 public static final int STRICT = 0x00000800;
363
364 // Bits not (yet) exposed in the public API either because they
365 // have different meanings for fields and methods and there is no
366 // way to distinguish between the two in this class, or because
367 // they are not Java programming language keywords
368 static final int BRIDGE = 0x00000040;
369 static final int VARARGS = 0x00000080;
370 static final int SYNTHETIC = 0x00001000;
371 static final int ANNOTATION = 0x00002000;
372 static final int ENUM = 0x00004000;
373 static final int MANDATED = 0x00008000;
374 static boolean isSynthetic(int mod) {
375 return (mod & SYNTHETIC) != 0;
376 }
377
378 static boolean isMandated(int mod) {
379 return (mod & MANDATED) != 0;
380 }
381
382 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
383 // the sets of modifiers are not guaranteed to be constants
384 // across time and Java SE releases. Therefore, it would not be
385 // appropriate to expose an external interface to this information
386 // that would allow the values to be treated as Java-level
387 // constants since the values could be constant folded and updates
388 // to the sets of modifiers missed. Thus, the fooModifiers()
389 // methods return an unchanging values for a given release, but a
390 // value that can potentially change over time.
391
392 /**
393 * The Java source modifiers that can be applied to a class.
394 * @jls 8.1.1 Class Modifiers
395 */
396 private static final int CLASS_MODIFIERS =
397 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
398 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
399 Modifier.STRICT;
400
401 /**
402 * The Java source modifiers that can be applied to an interface.
403 * @jls 9.1.1 Interface Modifiers
404 */
405 private static final int INTERFACE_MODIFIERS =
406 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
407 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
408
409
410 /**
411 * The Java source modifiers that can be applied to a constructor.
412 * @jls 8.8.3 Constructor Modifiers
413 */
414 private static final int CONSTRUCTOR_MODIFIERS =
415 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
416
417 /**
418 * The Java source modifiers that can be applied to a method.
419 * @jls 8.4.3 Method Modifiers
420 */
421 private static final int METHOD_MODIFIERS =
422 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
423 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
424 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
425
426 /**
427 * The Java source modifiers that can be applied to a field.
428 * @jls 8.3.1 Field Modifiers
429 */
430 private static final int FIELD_MODIFIERS =
431 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
432 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
433 Modifier.VOLATILE;
434
435 /**
436 * The Java source modifiers that can be applied to a method or constructor parameter.
437 * @jls 8.4.1 Formal Parameters
438 */
439 private static final int PARAMETER_MODIFIERS =
440 Modifier.FINAL;
441
442 static final int ACCESS_MODIFIERS =
443 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
444
445 /**
446 * Return an {@code int} value OR-ing together the source language
447 * modifiers that can be applied to a class.
448 * @return an {@code int} value OR-ing together the source language
449 * modifiers that can be applied to a class.
450 *
451 * @jls 8.1.1 Class Modifiers
452 * @since 1.7
453 */
454 public static int classModifiers() {
455 return CLASS_MODIFIERS;
456 }
457
458 /**
459 * Return an {@code int} value OR-ing together the source language
460 * modifiers that can be applied to an interface.
461 * @return an {@code int} value OR-ing together the source language
462 * modifiers that can be applied to an interface.
463 *
464 * @jls 9.1.1 Interface Modifiers
465 * @since 1.7
466 */
467 public static int interfaceModifiers() {
468 return INTERFACE_MODIFIERS;
469 }
470
471 /**
472 * Return an {@code int} value OR-ing together the source language
473 * modifiers that can be applied to a constructor.
474 * @return an {@code int} value OR-ing together the source language
475 * modifiers that can be applied to a constructor.
476 *
477 * @jls 8.8.3 Constructor Modifiers
478 * @since 1.7
479 */
480 public static int constructorModifiers() {
481 return CONSTRUCTOR_MODIFIERS;
482 }
483
484 /**
485 * Return an {@code int} value OR-ing together the source language
486 * modifiers that can be applied to a method.
487 * @return an {@code int} value OR-ing together the source language
488 * modifiers that can be applied to a method.
489 *
490 * @jls 8.4.3 Method Modifiers
491 * @since 1.7
492 */
493 public static int methodModifiers() {
494 return METHOD_MODIFIERS;
495 }
496
497 /**
498 * Return an {@code int} value OR-ing together the source language
499 * modifiers that can be applied to a field.
500 * @return an {@code int} value OR-ing together the source language
501 * modifiers that can be applied to a field.
502 *
503 * @jls 8.3.1 Field Modifiers
504 * @since 1.7
505 */
506 public static int fieldModifiers() {
507 return FIELD_MODIFIERS;
508 }
509
510 /**
511 * Return an {@code int} value OR-ing together the source language
512 * modifiers that can be applied to a parameter.
513 * @return an {@code int} value OR-ing together the source language
514 * modifiers that can be applied to a parameter.
515 *
516 * @jls 8.4.1 Formal Parameters
517 * @since 1.8
518 */
519 public static int parameterModifiers() {
520 return PARAMETER_MODIFIERS;
521 }
522 }