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
18 * 2 along with this work; if not, write to the Free Software Foundation,
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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
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 * Do not call.
48 */
49 @Deprecated(forRemoval=true, since="14")
50 public Modifier() {}
51
52
53 /**
54 * Return {@code true} if the integer argument includes the
55 * {@code public} modifier, {@code false} otherwise.
56 *
57 * @param mod a set of modifiers
58 * @return {@code true} if {@code mod} includes the
59 * {@code public} modifier; {@code false} otherwise.
60 */
61 public static boolean isPublic(int mod) {
62 return (mod & PUBLIC) != 0;
63 }
64
65 /**
66 * Return {@code true} if the integer argument includes the
67 * {@code private} modifier, {@code false} otherwise.
68 *
69 * @param mod a set of modifiers
70 * @return {@code true} if {@code mod} includes the
71 * {@code private} modifier; {@code false} otherwise.
72 */
73 public static boolean isPrivate(int mod) {
74 return (mod & PRIVATE) != 0;
75 }
76
77 /**
78 * Return {@code true} if the integer argument includes the
79 * {@code protected} modifier, {@code false} otherwise.
80 *
81 * @param mod a set of modifiers
82 * @return {@code true} if {@code mod} includes the
83 * {@code protected} modifier; {@code false} otherwise.
84 */
85 public static boolean isProtected(int mod) {
86 return (mod & PROTECTED) != 0;
87 }
88
89 /**
90 * Return {@code true} if the integer argument includes the
91 * {@code static} modifier, {@code false} otherwise.
92 *
93 * @param mod a set of modifiers
94 * @return {@code true} if {@code mod} includes the
95 * {@code static} modifier; {@code false} otherwise.
96 */
97 public static boolean isStatic(int mod) {
98 return (mod & STATIC) != 0;
99 }
100
101 /**
102 * Return {@code true} if the integer argument includes the
103 * {@code final} modifier, {@code false} otherwise.
104 *
105 * @param mod a set of modifiers
106 * @return {@code true} if {@code mod} includes the
107 * {@code final} modifier; {@code false} otherwise.
108 */
109 public static boolean isFinal(int mod) {
110 return (mod & FINAL) != 0;
111 }
112
113 /**
114 * Return {@code true} if the integer argument includes the
115 * {@code synchronized} modifier, {@code false} otherwise.
116 *
117 * @param mod a set of modifiers
118 * @return {@code true} if {@code mod} includes the
119 * {@code synchronized} modifier; {@code false} otherwise.
120 */
121 public static boolean isSynchronized(int mod) {
122 return (mod & SYNCHRONIZED) != 0;
123 }
124
125 /**
126 * Return {@code true} if the integer argument includes the
127 * {@code volatile} modifier, {@code false} otherwise.
128 *
129 * @param mod a set of modifiers
130 * @return {@code true} if {@code mod} includes the
131 * {@code volatile} modifier; {@code false} otherwise.
132 */
133 public static boolean isVolatile(int mod) {
134 return (mod & VOLATILE) != 0;
135 }
136
137 /**
138 * Return {@code true} if the integer argument includes the
139 * {@code transient} modifier, {@code false} otherwise.
140 *
141 * @param mod a set of modifiers
142 * @return {@code true} if {@code mod} includes the
143 * {@code transient} modifier; {@code false} otherwise.
144 */
145 public static boolean isTransient(int mod) {
146 return (mod & TRANSIENT) != 0;
147 }
148
149 /**
150 * Return {@code true} if the integer argument includes the
151 * {@code native} modifier, {@code false} otherwise.
152 *
153 * @param mod a set of modifiers
154 * @return {@code true} if {@code mod} includes the
155 * {@code native} modifier; {@code false} otherwise.
156 */
157 public static boolean isNative(int mod) {
158 return (mod & NATIVE) != 0;
159 }
160
161 /**
162 * Return {@code true} if the integer argument includes the
163 * {@code interface} modifier, {@code false} otherwise.
164 *
165 * @param mod a set of modifiers
166 * @return {@code true} if {@code mod} includes the
167 * {@code interface} modifier; {@code false} otherwise.
168 */
169 public static boolean isInterface(int mod) {
170 return (mod & INTERFACE) != 0;
171 }
172
173 /**
174 * Return {@code true} if the integer argument includes the
175 * {@code abstract} modifier, {@code false} otherwise.
176 *
177 * @param mod a set of modifiers
178 * @return {@code true} if {@code mod} includes the
179 * {@code abstract} modifier; {@code false} otherwise.
180 */
181 public static boolean isAbstract(int mod) {
182 return (mod & ABSTRACT) != 0;
183 }
184
185 /**
186 * Return {@code true} if the integer argument includes the
187 * {@code strictfp} modifier, {@code false} otherwise.
188 *
189 * @param mod a set of modifiers
190 * @return {@code true} if {@code mod} includes the
191 * {@code strictfp} modifier; {@code false} otherwise.
192 */
193 public static boolean isStrict(int mod) {
194 return (mod & STRICT) != 0;
195 }
196
197 /**
198 * Return a string describing the access modifier flags in
199 * the specified modifier. For example:
200 * <blockquote><pre>
201 * public final synchronized strictfp
202 * </pre></blockquote>
203 * The modifier names are returned in an order consistent with the
204 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
205 * <cite>The Java™ Language Specification</cite>.
206 * The full modifier ordering used by this method is:
207 * <blockquote> {@code
208 * public protected private abstract static final transient
209 * volatile synchronized native strictfp
210 * interface } </blockquote>
211 * The {@code interface} modifier discussed in this class is
212 * not a true modifier in the Java language and it appears after
213 * all other modifiers listed by this method. This method may
214 * return a string of modifiers that are not valid modifiers of a
215 * Java entity; in other words, no checking is done on the
216 * possible validity of the combination of modifiers represented
217 * by the input.
218 *
219 * Note that to perform such checking for a known kind of entity,
220 * such as a constructor or method, first AND the argument of
221 * {@code toString} with the appropriate mask from a method like
222 * {@link #constructorModifiers} or {@link #methodModifiers}.
223 *
224 * @param mod a set of modifiers
225 * @return a string representation of the set of modifiers
226 * represented by {@code mod}
227 */
228 public static String toString(int mod) {
229 StringJoiner sj = new StringJoiner(" ");
230
231 if ((mod & PUBLIC) != 0) sj.add("public");
232 if ((mod & PROTECTED) != 0) sj.add("protected");
233 if ((mod & PRIVATE) != 0) sj.add("private");
234
235 /* Canonical order */
236 if ((mod & ABSTRACT) != 0) sj.add("abstract");
237 if ((mod & STATIC) != 0) sj.add("static");
238 if ((mod & FINAL) != 0) sj.add("final");
239 if ((mod & TRANSIENT) != 0) sj.add("transient");
240 if ((mod & VOLATILE) != 0) sj.add("volatile");
241 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
242 if ((mod & NATIVE) != 0) sj.add("native");
243 if ((mod & STRICT) != 0) sj.add("strictfp");
244 if ((mod & INTERFACE) != 0) sj.add("interface");
245
246 return sj.toString();
247 }
248
249 /*
250 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
251 * <cite>The Java™ Virtual Machine Specification</cite>
252 */
253
254 /**
255 * The {@code int} value representing the {@code public}
256 * modifier.
257 */
258 public static final int PUBLIC = 0x00000001;
259
260 /**
261 * The {@code int} value representing the {@code private}
262 * modifier.
263 */
264 public static final int PRIVATE = 0x00000002;
265
266 /**
267 * The {@code int} value representing the {@code protected}
268 * modifier.
269 */
270 public static final int PROTECTED = 0x00000004;
271
272 /**
273 * The {@code int} value representing the {@code static}
274 * modifier.
275 */
276 public static final int STATIC = 0x00000008;
277
278 /**
279 * The {@code int} value representing the {@code final}
280 * modifier.
281 */
282 public static final int FINAL = 0x00000010;
283
284 /**
285 * The {@code int} value representing the {@code synchronized}
286 * modifier.
287 */
288 public static final int SYNCHRONIZED = 0x00000020;
289
290 /**
291 * The {@code int} value representing the {@code volatile}
292 * modifier.
293 */
294 public static final int VOLATILE = 0x00000040;
295
296 /**
297 * The {@code int} value representing the {@code transient}
298 * modifier.
299 */
300 public static final int TRANSIENT = 0x00000080;
301
302 /**
303 * The {@code int} value representing the {@code native}
304 * modifier.
305 */
306 public static final int NATIVE = 0x00000100;
307
308 /**
309 * The {@code int} value representing the {@code interface}
310 * modifier.
311 */
312 public static final int INTERFACE = 0x00000200;
313
314 /**
315 * The {@code int} value representing the {@code abstract}
316 * modifier.
317 */
318 public static final int ABSTRACT = 0x00000400;
319
320 /**
321 * The {@code int} value representing the {@code strictfp}
322 * modifier.
323 */
324 public static final int STRICT = 0x00000800;
325
326 // Bits not (yet) exposed in the public API either because they
327 // have different meanings for fields and methods and there is no
328 // way to distinguish between the two in this class, or because
329 // they are not Java programming language keywords
330 static final int BRIDGE = 0x00000040;
331 static final int VARARGS = 0x00000080;
332 static final int SYNTHETIC = 0x00001000;
333 static final int ANNOTATION = 0x00002000;
334 static final int ENUM = 0x00004000;
335 static final int MANDATED = 0x00008000;
336 static boolean isSynthetic(int mod) {
337 return (mod & SYNTHETIC) != 0;
338 }
339
340 static boolean isMandated(int mod) {
341 return (mod & MANDATED) != 0;
342 }
343
344 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
345 // the sets of modifiers are not guaranteed to be constants
346 // across time and Java SE releases. Therefore, it would not be
347 // appropriate to expose an external interface to this information
348 // that would allow the values to be treated as Java-level
349 // constants since the values could be constant folded and updates
350 // to the sets of modifiers missed. Thus, the fooModifiers()
351 // methods return an unchanging values for a given release, but a
352 // value that can potentially change over time.
353
354 /**
355 * The Java source modifiers that can be applied to a class.
356 * @jls 8.1.1 Class Modifiers
357 */
358 private static final int CLASS_MODIFIERS =
359 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
360 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
361 Modifier.STRICT;
362
363 /**
364 * The Java source modifiers that can be applied to an interface.
365 * @jls 9.1.1 Interface Modifiers
366 */
367 private static final int INTERFACE_MODIFIERS =
368 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
369 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
370
371
372 /**
373 * The Java source modifiers that can be applied to a constructor.
374 * @jls 8.8.3 Constructor Modifiers
375 */
376 private static final int CONSTRUCTOR_MODIFIERS =
377 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
378
379 /**
380 * The Java source modifiers that can be applied to a method.
381 * @jls8.4.3 Method Modifiers
382 */
383 private static final int METHOD_MODIFIERS =
384 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
385 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
386 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
387
388 /**
389 * The Java source modifiers that can be applied to a field.
390 * @jls 8.3.1 Field Modifiers
391 */
392 private static final int FIELD_MODIFIERS =
393 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
394 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
395 Modifier.VOLATILE;
396
397 /**
398 * The Java source modifiers that can be applied to a method or constructor parameter.
399 * @jls 8.4.1 Formal Parameters
400 */
401 private static final int PARAMETER_MODIFIERS =
402 Modifier.FINAL;
403
404 /**
405 *
406 */
407 static final int ACCESS_MODIFIERS =
408 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
409
410 /**
411 * Return an {@code int} value OR-ing together the source language
412 * modifiers that can be applied to a class.
413 * @return an {@code int} value OR-ing together the source language
414 * modifiers that can be applied to a class.
415 *
416 * @jls 8.1.1 Class Modifiers
417 * @since 1.7
418 */
419 public static int classModifiers() {
420 return CLASS_MODIFIERS;
421 }
422
423 /**
424 * Return an {@code int} value OR-ing together the source language
425 * modifiers that can be applied to an interface.
426 * @return an {@code int} value OR-ing together the source language
427 * modifiers that can be applied to an interface.
428 *
429 * @jls 9.1.1 Interface Modifiers
430 * @since 1.7
431 */
432 public static int interfaceModifiers() {
433 return INTERFACE_MODIFIERS;
434 }
435
436 /**
437 * Return an {@code int} value OR-ing together the source language
438 * modifiers that can be applied to a constructor.
439 * @return an {@code int} value OR-ing together the source language
440 * modifiers that can be applied to a constructor.
441 *
442 * @jls 8.8.3 Constructor Modifiers
443 * @since 1.7
444 */
445 public static int constructorModifiers() {
446 return CONSTRUCTOR_MODIFIERS;
447 }
448
449 /**
450 * Return an {@code int} value OR-ing together the source language
451 * modifiers that can be applied to a method.
452 * @return an {@code int} value OR-ing together the source language
453 * modifiers that can be applied to a method.
454 *
455 * @jls 8.4.3 Method Modifiers
456 * @since 1.7
457 */
458 public static int methodModifiers() {
459 return METHOD_MODIFIERS;
460 }
461
462 /**
463 * Return an {@code int} value OR-ing together the source language
464 * modifiers that can be applied to a field.
465 * @return an {@code int} value OR-ing together the source language
466 * modifiers that can be applied to a field.
467 *
468 * @jls 8.3.1 Field Modifiers
469 * @since 1.7
470 */
471 public static int fieldModifiers() {
472 return FIELD_MODIFIERS;
473 }
474
475 /**
476 * Return an {@code int} value OR-ing together the source language
477 * modifiers that can be applied to a parameter.
478 * @return an {@code int} value OR-ing together the source language
479 * modifiers that can be applied to a parameter.
480 *
481 * @jls 8.4.1 Formal Parameters
482 * @since 1.8
483 */
484 public static int parameterModifiers() {
485 return PARAMETER_MODIFIERS;
486 }
487 }