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
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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 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 /**
48 * Return {@code true} if the integer argument includes the
49 * {@code public} modifier, {@code false} otherwise.
50 *
51 * @param mod a set of modifiers
52 * @return {@code true} if {@code mod} includes the
53 * {@code public} modifier; {@code false} otherwise.
54 */
55 public static boolean isPublic(int mod) {
56 return (mod & PUBLIC) != 0;
57 }
58
59 /**
60 * Return {@code true} if the integer argument includes the
61 * {@code private} modifier, {@code false} otherwise.
62 *
63 * @param mod a set of modifiers
64 * @return {@code true} if {@code mod} includes the
65 * {@code private} modifier; {@code false} otherwise.
66 */
67 public static boolean isPrivate(int mod) {
68 return (mod & PRIVATE) != 0;
69 }
70
71 /**
72 * Return {@code true} if the integer argument includes the
73 * {@code protected} modifier, {@code false} otherwise.
74 *
75 * @param mod a set of modifiers
76 * @return {@code true} if {@code mod} includes the
77 * {@code protected} modifier; {@code false} otherwise.
78 */
79 public static boolean isProtected(int mod) {
80 return (mod & PROTECTED) != 0;
81 }
82
83 /**
84 * Return {@code true} if the integer argument includes the
85 * {@code static} modifier, {@code false} otherwise.
86 *
87 * @param mod a set of modifiers
88 * @return {@code true} if {@code mod} includes the
89 * {@code static} modifier; {@code false} otherwise.
90 */
91 public static boolean isStatic(int mod) {
92 return (mod & STATIC) != 0;
93 }
94
95 /**
96 * Return {@code true} if the integer argument includes the
97 * {@code final} modifier, {@code false} otherwise.
98 *
99 * @param mod a set of modifiers
100 * @return {@code true} if {@code mod} includes the
101 * {@code final} modifier; {@code false} otherwise.
102 */
103 public static boolean isFinal(int mod) {
104 return (mod & FINAL) != 0;
105 }
106
107 /**
108 * Return {@code true} if the integer argument includes the
109 * {@code synchronized} modifier, {@code false} otherwise.
110 *
111 * @param mod a set of modifiers
112 * @return {@code true} if {@code mod} includes the
113 * {@code synchronized} modifier; {@code false} otherwise.
114 */
115 public static boolean isSynchronized(int mod) {
116 return (mod & SYNCHRONIZED) != 0;
117 }
118
119 /**
120 * Return {@code true} if the integer argument includes the
121 * {@code volatile} modifier, {@code false} otherwise.
122 *
123 * @param mod a set of modifiers
124 * @return {@code true} if {@code mod} includes the
125 * {@code volatile} modifier; {@code false} otherwise.
126 */
127 public static boolean isVolatile(int mod) {
128 return (mod & VOLATILE) != 0;
129 }
130
131 /**
132 * Return {@code true} if the integer argument includes the
133 * {@code transient} modifier, {@code false} otherwise.
134 *
135 * @param mod a set of modifiers
136 * @return {@code true} if {@code mod} includes the
137 * {@code transient} modifier; {@code false} otherwise.
138 */
139 public static boolean isTransient(int mod) {
140 return (mod & TRANSIENT) != 0;
141 }
142
143 /**
144 * Return {@code true} if the integer argument includes the
145 * {@code native} modifier, {@code false} otherwise.
146 *
147 * @param mod a set of modifiers
148 * @return {@code true} if {@code mod} includes the
149 * {@code native} modifier; {@code false} otherwise.
150 */
151 public static boolean isNative(int mod) {
152 return (mod & NATIVE) != 0;
153 }
154
155 /**
156 * Return {@code true} if the integer argument includes the
157 * {@code interface} modifier, {@code false} otherwise.
158 *
159 * @param mod a set of modifiers
160 * @return {@code true} if {@code mod} includes the
161 * {@code interface} modifier; {@code false} otherwise.
162 */
163 public static boolean isInterface(int mod) {
164 return (mod & INTERFACE) != 0;
165 }
166
167 /**
168 * Return {@code true} if the integer argument includes the
169 * {@code abstract} modifier, {@code false} otherwise.
170 *
171 * @param mod a set of modifiers
172 * @return {@code true} if {@code mod} includes the
173 * {@code abstract} modifier; {@code false} otherwise.
174 */
175 public static boolean isAbstract(int mod) {
176 return (mod & ABSTRACT) != 0;
177 }
178
179 /**
180 * Return {@code true} if the integer argument includes the
181 * {@code strictfp} modifier, {@code false} otherwise.
182 *
183 * @param mod a set of modifiers
184 * @return {@code true} if {@code mod} includes the
185 * {@code strictfp} modifier; {@code false} otherwise.
186 */
187 public static boolean isStrict(int mod) {
188 return (mod & STRICT) != 0;
189 }
190
191 /**
192 * Return a string describing the access modifier flags in
193 * the specified modifier. For example:
194 * <blockquote><pre>
195 * public final synchronized strictfp
196 * </pre></blockquote>
197 * The modifier names are returned in an order consistent with the
198 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
199 * <cite>The Java™ Language Specification</cite>.
200 * The full modifier ordering used by this method is:
201 * <blockquote> {@code
202 * public protected private abstract static final transient
203 * volatile synchronized native strictfp
204 * interface } </blockquote>
205 * The {@code interface} modifier discussed in this class is
206 * not a true modifier in the Java language and it appears after
207 * all other modifiers listed by this method. This method may
208 * return a string of modifiers that are not valid modifiers of a
209 * Java entity; in other words, no checking is done on the
210 * possible validity of the combination of modifiers represented
211 * by the input.
212 *
213 * Note that to perform such checking for a known kind of entity,
214 * such as a constructor or method, first AND the argument of
215 * {@code toString} with the appropriate mask from a method like
216 * {@link #constructorModifiers} or {@link #methodModifiers}.
217 *
218 * @param mod a set of modifiers
219 * @return a string representation of the set of modifiers
220 * represented by {@code mod}
221 */
222 public static String toString(int mod) {
223 StringJoiner sj = new StringJoiner(" ");
224
225 if ((mod & PUBLIC) != 0) sj.add("public");
226 if ((mod & PROTECTED) != 0) sj.add("protected");
227 if ((mod & PRIVATE) != 0) sj.add("private");
228
229 /* Canonical order */
230 if ((mod & ABSTRACT) != 0) sj.add("abstract");
231 if ((mod & STATIC) != 0) sj.add("static");
232 if ((mod & FINAL) != 0) sj.add("final");
233 if ((mod & TRANSIENT) != 0) sj.add("transient");
234 if ((mod & VOLATILE) != 0) sj.add("volatile");
235 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
236 if ((mod & NATIVE) != 0) sj.add("native");
237 if ((mod & STRICT) != 0) sj.add("strictfp");
238 if ((mod & INTERFACE) != 0) sj.add("interface");
239
240 return sj.toString();
241 }
242
243 /*
244 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
245 * <cite>The Java™ Virtual Machine Specification</cite>
246 */
247
248 /**
249 * The {@code int} value representing the {@code public}
250 * modifier.
251 */
252 public static final int PUBLIC = 0x00000001;
253
254 /**
255 * The {@code int} value representing the {@code private}
256 * modifier.
257 */
258 public static final int PRIVATE = 0x00000002;
259
260 /**
261 * The {@code int} value representing the {@code protected}
262 * modifier.
263 */
264 public static final int PROTECTED = 0x00000004;
265
266 /**
267 * The {@code int} value representing the {@code static}
268 * modifier.
269 */
270 public static final int STATIC = 0x00000008;
271
272 /**
273 * The {@code int} value representing the {@code final}
274 * modifier.
275 */
276 public static final int FINAL = 0x00000010;
277
278 /**
279 * The {@code int} value representing the {@code synchronized}
280 * modifier.
281 */
282 public static final int SYNCHRONIZED = 0x00000020;
283
284 /**
285 * The {@code int} value representing the {@code volatile}
286 * modifier.
287 */
288 public static final int VOLATILE = 0x00000040;
289
290 /**
291 * The {@code int} value representing the {@code transient}
292 * modifier.
293 */
294 public static final int TRANSIENT = 0x00000080;
295
296 /**
297 * The {@code int} value representing the {@code native}
298 * modifier.
299 */
300 public static final int NATIVE = 0x00000100;
301
302 /**
303 * The {@code int} value representing the {@code interface}
304 * modifier.
305 */
306 public static final int INTERFACE = 0x00000200;
307
308 /**
309 * The {@code int} value representing the {@code abstract}
310 * modifier.
311 */
312 public static final int ABSTRACT = 0x00000400;
313
314 /**
315 * The {@code int} value representing the {@code strictfp}
316 * modifier.
317 */
318 public static final int STRICT = 0x00000800;
319
320 // Bits not (yet) exposed in the public API either because they
321 // have different meanings for fields and methods and there is no
322 // way to distinguish between the two in this class, or because
323 // they are not Java programming language keywords
324 static final int BRIDGE = 0x00000040;
325 static final int VARARGS = 0x00000080;
326 static final int SYNTHETIC = 0x00001000;
327 static final int ANNOTATION = 0x00002000;
328 static final int ENUM = 0x00004000;
329 static final int MANDATED = 0x00008000;
330 static boolean isSynthetic(int mod) {
331 return (mod & SYNTHETIC) != 0;
332 }
333
334 static boolean isMandated(int mod) {
335 return (mod & MANDATED) != 0;
336 }
337
338 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
339 // the sets of modifiers are not guaranteed to be constants
340 // across time and Java SE releases. Therefore, it would not be
341 // appropriate to expose an external interface to this information
342 // that would allow the values to be treated as Java-level
343 // constants since the values could be constant folded and updates
344 // to the sets of modifiers missed. Thus, the fooModifiers()
345 // methods return an unchanging values for a given release, but a
346 // value that can potentially change over time.
347
348 /**
349 * The Java source modifiers that can be applied to a class.
350 * @jls 8.1.1 Class Modifiers
351 */
352 private static final int CLASS_MODIFIERS =
353 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
354 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
355 Modifier.STRICT;
356
357 /**
358 * The Java source modifiers that can be applied to an interface.
359 * @jls 9.1.1 Interface Modifiers
360 */
361 private static final int INTERFACE_MODIFIERS =
362 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
363 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
364
365
366 /**
367 * The Java source modifiers that can be applied to a constructor.
368 * @jls 8.8.3 Constructor Modifiers
369 */
370 private static final int CONSTRUCTOR_MODIFIERS =
371 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
372
373 /**
374 * The Java source modifiers that can be applied to a method.
375 * @jls8.4.3 Method Modifiers
376 */
377 private static final int METHOD_MODIFIERS =
378 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
379 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
380 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
381
382 /**
383 * The Java source modifiers that can be applied to a field.
384 * @jls 8.3.1 Field Modifiers
385 */
386 private static final int FIELD_MODIFIERS =
387 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
388 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
389 Modifier.VOLATILE;
390
391 /**
392 * The Java source modifiers that can be applied to a method or constructor parameter.
393 * @jls 8.4.1 Formal Parameters
394 */
395 private static final int PARAMETER_MODIFIERS =
396 Modifier.FINAL;
397
398 /**
399 *
400 */
401 static final int ACCESS_MODIFIERS =
402 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
403
404 /**
405 * Return an {@code int} value OR-ing together the source language
406 * modifiers that can be applied to a class.
407 * @return an {@code int} value OR-ing together the source language
408 * modifiers that can be applied to a class.
409 *
410 * @jls 8.1.1 Class Modifiers
411 * @since 1.7
412 */
413 public static int classModifiers() {
414 return CLASS_MODIFIERS;
415 }
416
417 /**
418 * Return an {@code int} value OR-ing together the source language
419 * modifiers that can be applied to an interface.
420 * @return an {@code int} value OR-ing together the source language
421 * modifiers that can be applied to an interface.
422 *
423 * @jls 9.1.1 Interface Modifiers
424 * @since 1.7
425 */
426 public static int interfaceModifiers() {
427 return INTERFACE_MODIFIERS;
428 }
429
430 /**
431 * Return an {@code int} value OR-ing together the source language
432 * modifiers that can be applied to a constructor.
433 * @return an {@code int} value OR-ing together the source language
434 * modifiers that can be applied to a constructor.
435 *
436 * @jls 8.8.3 Constructor Modifiers
437 * @since 1.7
438 */
439 public static int constructorModifiers() {
440 return CONSTRUCTOR_MODIFIERS;
441 }
442
443 /**
444 * Return an {@code int} value OR-ing together the source language
445 * modifiers that can be applied to a method.
446 * @return an {@code int} value OR-ing together the source language
447 * modifiers that can be applied to a method.
448 *
449 * @jls 8.4.3 Method Modifiers
450 * @since 1.7
451 */
452 public static int methodModifiers() {
453 return METHOD_MODIFIERS;
454 }
455
456 /**
457 * Return an {@code int} value OR-ing together the source language
458 * modifiers that can be applied to a field.
459 * @return an {@code int} value OR-ing together the source language
460 * modifiers that can be applied to a field.
461 *
462 * @jls 8.3.1 Field Modifiers
463 * @since 1.7
464 */
465 public static int fieldModifiers() {
466 return FIELD_MODIFIERS;
467 }
468
469 /**
470 * Return an {@code int} value OR-ing together the source language
471 * modifiers that can be applied to a parameter.
472 * @return an {@code int} value OR-ing together the source language
473 * modifiers that can be applied to a parameter.
474 *
475 * @jls 8.4.1 Formal Parameters
476 * @since 1.8
477 */
478 public static int parameterModifiers() {
479 return PARAMETER_MODIFIERS;
480 }
481 }