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.security.AccessController;
29 import java.util.StringJoiner;
30 import jdk.internal.reflect.LangReflectAccess;
31 import jdk.internal.reflect.ReflectionFactory;
32
33 /**
34 * The Modifier class provides {@code static} methods and
35 * constants to decode class and member access modifiers. The sets of
36 * modifiers are represented as integers with distinct bit positions
37 * representing different modifiers. The values for the constants
38 * representing the modifiers are taken from the tables in sections 4.1, 4.4, 4.5, and 4.7 of
39 * <cite>The Java™ Virtual Machine Specification</cite>.
40 *
41 * @see Class#getModifiers()
42 * @see Member#getModifiers()
43 *
44 * @author Nakul Saraiya
45 * @author Kenneth Russell
46 * @since 1.1
47 */
48 public class Modifier {
49
50 /*
51 * Bootstrapping protocol between java.lang and java.lang.reflect
52 * packages
53 */
54 static {
55 ReflectionFactory factory = AccessController.doPrivileged(
56 new ReflectionFactory.GetReflectionFactoryAction());
57 factory.setLangReflectAccess(new java.lang.reflect.ReflectAccess());
58 }
59
60 /**
61 * Return {@code true} if the integer argument includes the
62 * {@code public} modifier, {@code false} otherwise.
63 *
64 * @param mod a set of modifiers
65 * @return {@code true} if {@code mod} includes the
66 * {@code public} modifier; {@code false} otherwise.
67 */
68 public static boolean isPublic(int mod) {
69 return (mod & PUBLIC) != 0;
70 }
71
72 /**
73 * Return {@code true} if the integer argument includes the
74 * {@code private} modifier, {@code false} otherwise.
75 *
76 * @param mod a set of modifiers
77 * @return {@code true} if {@code mod} includes the
78 * {@code private} modifier; {@code false} otherwise.
79 */
80 public static boolean isPrivate(int mod) {
81 return (mod & PRIVATE) != 0;
82 }
83
84 /**
85 * Return {@code true} if the integer argument includes the
86 * {@code protected} modifier, {@code false} otherwise.
87 *
88 * @param mod a set of modifiers
89 * @return {@code true} if {@code mod} includes the
90 * {@code protected} modifier; {@code false} otherwise.
91 */
92 public static boolean isProtected(int mod) {
93 return (mod & PROTECTED) != 0;
94 }
95
96 /**
97 * Return {@code true} if the integer argument includes the
98 * {@code static} modifier, {@code false} otherwise.
99 *
100 * @param mod a set of modifiers
101 * @return {@code true} if {@code mod} includes the
102 * {@code static} modifier; {@code false} otherwise.
103 */
104 public static boolean isStatic(int mod) {
105 return (mod & STATIC) != 0;
106 }
107
108 /**
109 * Return {@code true} if the integer argument includes the
110 * {@code final} modifier, {@code false} otherwise.
111 *
112 * @param mod a set of modifiers
113 * @return {@code true} if {@code mod} includes the
114 * {@code final} modifier; {@code false} otherwise.
115 */
116 public static boolean isFinal(int mod) {
117 return (mod & FINAL) != 0;
118 }
119
120 /**
121 * Return {@code true} if the integer argument includes the
122 * {@code synchronized} modifier, {@code false} otherwise.
123 *
124 * @param mod a set of modifiers
125 * @return {@code true} if {@code mod} includes the
126 * {@code synchronized} modifier; {@code false} otherwise.
127 */
128 public static boolean isSynchronized(int mod) {
129 return (mod & SYNCHRONIZED) != 0;
130 }
131
132 /**
133 * Return {@code true} if the integer argument includes the
134 * {@code volatile} modifier, {@code false} otherwise.
135 *
136 * @param mod a set of modifiers
137 * @return {@code true} if {@code mod} includes the
138 * {@code volatile} modifier; {@code false} otherwise.
139 */
140 public static boolean isVolatile(int mod) {
141 return (mod & VOLATILE) != 0;
142 }
143
144 /**
145 * Return {@code true} if the integer argument includes the
146 * {@code transient} modifier, {@code false} otherwise.
147 *
148 * @param mod a set of modifiers
149 * @return {@code true} if {@code mod} includes the
150 * {@code transient} modifier; {@code false} otherwise.
151 */
152 public static boolean isTransient(int mod) {
153 return (mod & TRANSIENT) != 0;
154 }
155
156 /**
157 * Return {@code true} if the integer argument includes the
158 * {@code native} modifier, {@code false} otherwise.
159 *
160 * @param mod a set of modifiers
161 * @return {@code true} if {@code mod} includes the
162 * {@code native} modifier; {@code false} otherwise.
163 */
164 public static boolean isNative(int mod) {
165 return (mod & NATIVE) != 0;
166 }
167
168 /**
169 * Return {@code true} if the integer argument includes the
170 * {@code interface} modifier, {@code false} otherwise.
171 *
172 * @param mod a set of modifiers
173 * @return {@code true} if {@code mod} includes the
174 * {@code interface} modifier; {@code false} otherwise.
175 */
176 public static boolean isInterface(int mod) {
177 return (mod & INTERFACE) != 0;
178 }
179
180 /**
181 * Return {@code true} if the integer argument includes the
182 * {@code abstract} modifier, {@code false} otherwise.
183 *
184 * @param mod a set of modifiers
185 * @return {@code true} if {@code mod} includes the
186 * {@code abstract} modifier; {@code false} otherwise.
187 */
188 public static boolean isAbstract(int mod) {
189 return (mod & ABSTRACT) != 0;
190 }
191
192 /**
193 * Return {@code true} if the integer argument includes the
194 * {@code strictfp} modifier, {@code false} otherwise.
195 *
196 * @param mod a set of modifiers
197 * @return {@code true} if {@code mod} includes the
198 * {@code strictfp} modifier; {@code false} otherwise.
199 */
200 public static boolean isStrict(int mod) {
201 return (mod & STRICT) != 0;
202 }
203
204 /**
205 * Return a string describing the access modifier flags in
206 * the specified modifier. For example:
207 * <blockquote><pre>
208 * public final synchronized strictfp
209 * </pre></blockquote>
210 * The modifier names are returned in an order consistent with the
211 * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of
212 * <cite>The Java™ Language Specification</cite>.
213 * The full modifier ordering used by this method is:
214 * <blockquote> {@code
215 * public protected private abstract static final transient
216 * volatile synchronized native strictfp
217 * interface } </blockquote>
218 * The {@code interface} modifier discussed in this class is
219 * not a true modifier in the Java language and it appears after
220 * all other modifiers listed by this method. This method may
221 * return a string of modifiers that are not valid modifiers of a
222 * Java entity; in other words, no checking is done on the
223 * possible validity of the combination of modifiers represented
224 * by the input.
225 *
226 * Note that to perform such checking for a known kind of entity,
227 * such as a constructor or method, first AND the argument of
228 * {@code toString} with the appropriate mask from a method like
229 * {@link #constructorModifiers} or {@link #methodModifiers}.
230 *
231 * @param mod a set of modifiers
232 * @return a string representation of the set of modifiers
233 * represented by {@code mod}
234 */
235 public static String toString(int mod) {
236 StringJoiner sj = new StringJoiner(" ");
237
238 if ((mod & PUBLIC) != 0) sj.add("public");
239 if ((mod & PROTECTED) != 0) sj.add("protected");
240 if ((mod & PRIVATE) != 0) sj.add("private");
241
242 /* Canonical order */
243 if ((mod & ABSTRACT) != 0) sj.add("abstract");
244 if ((mod & STATIC) != 0) sj.add("static");
245 if ((mod & FINAL) != 0) sj.add("final");
246 if ((mod & TRANSIENT) != 0) sj.add("transient");
247 if ((mod & VOLATILE) != 0) sj.add("volatile");
248 if ((mod & SYNCHRONIZED) != 0) sj.add("synchronized");
249 if ((mod & NATIVE) != 0) sj.add("native");
250 if ((mod & STRICT) != 0) sj.add("strictfp");
251 if ((mod & INTERFACE) != 0) sj.add("interface");
252
253 return sj.toString();
254 }
255
256 /*
257 * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
258 * <cite>The Java™ Virtual Machine Specification</cite>
259 */
260
261 /**
262 * The {@code int} value representing the {@code public}
263 * modifier.
264 */
265 public static final int PUBLIC = 0x00000001;
266
267 /**
268 * The {@code int} value representing the {@code private}
269 * modifier.
270 */
271 public static final int PRIVATE = 0x00000002;
272
273 /**
274 * The {@code int} value representing the {@code protected}
275 * modifier.
276 */
277 public static final int PROTECTED = 0x00000004;
278
279 /**
280 * The {@code int} value representing the {@code static}
281 * modifier.
282 */
283 public static final int STATIC = 0x00000008;
284
285 /**
286 * The {@code int} value representing the {@code final}
287 * modifier.
288 */
289 public static final int FINAL = 0x00000010;
290
291 /**
292 * The {@code int} value representing the {@code synchronized}
293 * modifier.
294 */
295 public static final int SYNCHRONIZED = 0x00000020;
296
297 /**
298 * The {@code int} value representing the {@code volatile}
299 * modifier.
300 */
301 public static final int VOLATILE = 0x00000040;
302
303 /**
304 * The {@code int} value representing the {@code transient}
305 * modifier.
306 */
307 public static final int TRANSIENT = 0x00000080;
308
309 /**
310 * The {@code int} value representing the {@code native}
311 * modifier.
312 */
313 public static final int NATIVE = 0x00000100;
314
315 /**
316 * The {@code int} value representing the {@code interface}
317 * modifier.
318 */
319 public static final int INTERFACE = 0x00000200;
320
321 /**
322 * The {@code int} value representing the {@code abstract}
323 * modifier.
324 */
325 public static final int ABSTRACT = 0x00000400;
326
327 /**
328 * The {@code int} value representing the {@code strictfp}
329 * modifier.
330 */
331 public static final int STRICT = 0x00000800;
332
333 // Bits not (yet) exposed in the public API either because they
334 // have different meanings for fields and methods and there is no
335 // way to distinguish between the two in this class, or because
336 // they are not Java programming language keywords
337 static final int BRIDGE = 0x00000040;
338 static final int VARARGS = 0x00000080;
339 static final int SYNTHETIC = 0x00001000;
340 static final int ANNOTATION = 0x00002000;
341 static final int ENUM = 0x00004000;
342 static final int MANDATED = 0x00008000;
343 static boolean isSynthetic(int mod) {
344 return (mod & SYNTHETIC) != 0;
345 }
346
347 static boolean isMandated(int mod) {
348 return (mod & MANDATED) != 0;
349 }
350
351 // Note on the FOO_MODIFIERS fields and fooModifiers() methods:
352 // the sets of modifiers are not guaranteed to be constants
353 // across time and Java SE releases. Therefore, it would not be
354 // appropriate to expose an external interface to this information
355 // that would allow the values to be treated as Java-level
356 // constants since the values could be constant folded and updates
357 // to the sets of modifiers missed. Thus, the fooModifiers()
358 // methods return an unchanging values for a given release, but a
359 // value that can potentially change over time.
360
361 /**
362 * The Java source modifiers that can be applied to a class.
363 * @jls 8.1.1 Class Modifiers
364 */
365 private static final int CLASS_MODIFIERS =
366 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
367 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
368 Modifier.STRICT;
369
370 /**
371 * The Java source modifiers that can be applied to an interface.
372 * @jls 9.1.1 Interface Modifiers
373 */
374 private static final int INTERFACE_MODIFIERS =
375 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
376 Modifier.ABSTRACT | Modifier.STATIC | Modifier.STRICT;
377
378
379 /**
380 * The Java source modifiers that can be applied to a constructor.
381 * @jls 8.8.3 Constructor Modifiers
382 */
383 private static final int CONSTRUCTOR_MODIFIERS =
384 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
385
386 /**
387 * The Java source modifiers that can be applied to a method.
388 * @jls8.4.3 Method Modifiers
389 */
390 private static final int METHOD_MODIFIERS =
391 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
392 Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL |
393 Modifier.SYNCHRONIZED | Modifier.NATIVE | Modifier.STRICT;
394
395 /**
396 * The Java source modifiers that can be applied to a field.
397 * @jls 8.3.1 Field Modifiers
398 */
399 private static final int FIELD_MODIFIERS =
400 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE |
401 Modifier.STATIC | Modifier.FINAL | Modifier.TRANSIENT |
402 Modifier.VOLATILE;
403
404 /**
405 * The Java source modifiers that can be applied to a method or constructor parameter.
406 * @jls 8.4.1 Formal Parameters
407 */
408 private static final int PARAMETER_MODIFIERS =
409 Modifier.FINAL;
410
411 /**
412 *
413 */
414 static final int ACCESS_MODIFIERS =
415 Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE;
416
417 /**
418 * Return an {@code int} value OR-ing together the source language
419 * modifiers that can be applied to a class.
420 * @return an {@code int} value OR-ing together the source language
421 * modifiers that can be applied to a class.
422 *
423 * @jls 8.1.1 Class Modifiers
424 * @since 1.7
425 */
426 public static int classModifiers() {
427 return CLASS_MODIFIERS;
428 }
429
430 /**
431 * Return an {@code int} value OR-ing together the source language
432 * modifiers that can be applied to an interface.
433 * @return an {@code int} value OR-ing together the source language
434 * modifiers that can be applied to an interface.
435 *
436 * @jls 9.1.1 Interface Modifiers
437 * @since 1.7
438 */
439 public static int interfaceModifiers() {
440 return INTERFACE_MODIFIERS;
441 }
442
443 /**
444 * Return an {@code int} value OR-ing together the source language
445 * modifiers that can be applied to a constructor.
446 * @return an {@code int} value OR-ing together the source language
447 * modifiers that can be applied to a constructor.
448 *
449 * @jls 8.8.3 Constructor Modifiers
450 * @since 1.7
451 */
452 public static int constructorModifiers() {
453 return CONSTRUCTOR_MODIFIERS;
454 }
455
456 /**
457 * Return an {@code int} value OR-ing together the source language
458 * modifiers that can be applied to a method.
459 * @return an {@code int} value OR-ing together the source language
460 * modifiers that can be applied to a method.
461 *
462 * @jls 8.4.3 Method Modifiers
463 * @since 1.7
464 */
465 public static int methodModifiers() {
466 return METHOD_MODIFIERS;
467 }
468
469 /**
470 * Return an {@code int} value OR-ing together the source language
471 * modifiers that can be applied to a field.
472 * @return an {@code int} value OR-ing together the source language
473 * modifiers that can be applied to a field.
474 *
475 * @jls 8.3.1 Field Modifiers
476 * @since 1.7
477 */
478 public static int fieldModifiers() {
479 return FIELD_MODIFIERS;
480 }
481
482 /**
483 * Return an {@code int} value OR-ing together the source language
484 * modifiers that can be applied to a parameter.
485 * @return an {@code int} value OR-ing together the source language
486 * modifiers that can be applied to a parameter.
487 *
488 * @jls 8.4.1 Formal Parameters
489 * @since 1.8
490 */
491 public static int parameterModifiers() {
492 return PARAMETER_MODIFIERS;
493 }
494 }