1 /*
2 * Copyright (c) 2021, 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
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 jdk.internal.javac.PreviewFeature;
29 import jdk.internal.misc.PreviewFeatures;
30
31 import java.util.Collections;
32 import java.util.Objects;
33 import java.util.Map;
34 import java.util.Set;
35 import java.util.function.Function;
36 import static java.util.Map.entry;
37
38 /**
39 * Represents a JVM access or module-related flag on a runtime member,
40 * such as a {@linkplain Class class}, {@linkplain Field field}, or
41 * {@linkplain Executable method}.
42 *
43 * <P>JVM access and module-related flags are related to, but distinct
44 * from Java language {@linkplain Modifier modifiers}. Some modifiers
45 * and access flags have a one-to-one correspondence, such as {@code
46 * public}. In other cases, some language-level modifiers do
47 * <em>not</em> have an access flag, such as {@code sealed} (JVMS
48 * {@jvms 4.7.31}) and some access flags have no corresponding
49 * modifier, such as {@linkplain #SYNTHETIC synthetic}.
50 *
51 * <p>The values for the constants representing the access and module
52 * flags are taken from sections of <cite>The Java Virtual Machine
53 * Specification</cite> including {@jvms 4.1} (class access and
54 * property modifiers), {@jvms 4.5} (field access and property flags),
55 * {@jvms 4.6} (method access and property flags), {@jvms 4.7.6}
56 * (nested class access and property flags), {@jvms 4.7.24} (method
57 * parameters), and {@jvms 4.7.25} (module flags and requires,
58 * exports, and opens flags).
59 *
60 * <p>The {@linkplain #mask() mask} values for the different access
61 * flags are <em>not</em> distinct. Flags are defined for different
62 * kinds of JVM structures and the same bit position has different
63 * meanings in different contexts. For example, {@code 0x0000_0040}
64 * indicates a {@link #VOLATILE volatile} field but a {@linkplain
65 * #BRIDGE bridge method}; {@code 0x0000_0080} indicates a {@link
66 * #TRANSIENT transient} field but a {@linkplain #VARARGS variable
67 * arity (varargs)} method.
68 *
69 * @implSpec
70 * The access flag constants are ordered by non-decreasing mask
71 * value; that is the mask value of a constant is greater than or
72 * equal to the mask value of an immediate neighbor to its (syntactic)
73 * left. If new constants are added, this property will be
74 * maintained. That implies new constants will not necessarily be
75 * added at the end of the existing list.
76 *
77 * @apiNote
78 * The JVM class file format has a {@linkplain ClassFileFormatVersion new version} defined for each new
79 * {@linkplain Runtime.Version#feature() feature release}. A new class
80 * file version may define new access flags or retire old ones. {@code
81 * AccessFlag} is intended to model the set of access flags across
82 * class file format versions. The range of versions an access flag is
83 * recognized is not explicitly indicated in this API. See the current
84 * <cite>The Java Virtual Machine Specification</cite> for
85 * details. Unless otherwise indicated, access flags can be assumed to
86 * be recognized in the {@linkplain Runtime#version() current
87 * version}.
88 *
89 * @see java.lang.reflect.Modifier
90 * @see java.lang.module.ModuleDescriptor.Modifier
91 * @see java.lang.module.ModuleDescriptor.Requires.Modifier
92 * @see java.lang.module.ModuleDescriptor.Exports.Modifier
93 * @see java.lang.module.ModuleDescriptor.Opens.Modifier
94 * @see java.compiler/javax.lang.model.element.Modifier
95 * @since 20
96 */
97 @SuppressWarnings("doclint:reference") // cross-module link
98 public enum AccessFlag {
99 // Note to maintainers: anonymous class instances are used rather
100 // than lambdas to initialize the functions used for the
101 // cffvToLocations field to avoid using lambdas too early in JDK
102 // initialization.
103
104 /**
105 * The access flag {@code ACC_PUBLIC}, corresponding to the source
106 * modifier {@link Modifier#PUBLIC public}, with a mask value of
107 * <code>{@value "0x%04x" Modifier#PUBLIC}</code>.
108 */
109 PUBLIC(Modifier.PUBLIC, true,
110 Location.SET_PUBLIC_1,
111 new Function<ClassFileFormatVersion, Set<Location>>() {
112 @Override
113 public Set<Location> apply(ClassFileFormatVersion cffv) {
114 return (cffv == ClassFileFormatVersion.RELEASE_0) ?
115 Location.SET_CLASS_FIELD_METHOD:
116 Location.SET_PUBLIC_1;
117 }
118 }),
119
120 /**
121 * The access flag {@code ACC_PRIVATE}, corresponding to the
122 * source modifier {@link Modifier#PRIVATE private}, with a mask
123 * value of <code>{@value "0x%04x" Modifier#PRIVATE}</code>.
124 */
125 PRIVATE(Modifier.PRIVATE, true, Location.SET_FIELD_METHOD_INNER_CLASS,
126 new Function<ClassFileFormatVersion, Set<Location>>() {
127 @Override
128 public Set<Location> apply(ClassFileFormatVersion cffv) {
129 return (cffv == ClassFileFormatVersion.RELEASE_0) ?
130 Location.SET_FIELD_METHOD:
131 Location.SET_FIELD_METHOD_INNER_CLASS;
132 }
133 }),
134
135 /**
136 * The access flag {@code ACC_PROTECTED}, corresponding to the
137 * source modifier {@link Modifier#PROTECTED protected}, with a mask
138 * value of <code>{@value "0x%04x" Modifier#PROTECTED}</code>.
139 */
140 PROTECTED(Modifier.PROTECTED, true, Location.SET_FIELD_METHOD_INNER_CLASS,
141 new Function<ClassFileFormatVersion, Set<Location>>() {
142 @Override
143 public Set<Location> apply(ClassFileFormatVersion cffv) {
144 return (cffv == ClassFileFormatVersion.RELEASE_0) ?
145 Location.SET_FIELD_METHOD:
146 Location.SET_FIELD_METHOD_INNER_CLASS;
147 }
148 }),
149
150 /**
151 * The access flag {@code ACC_STATIC}, corresponding to the source
152 * modifier {@link Modifier#STATIC static}, with a mask value of
153 * <code>{@value "0x%04x" Modifier#STATIC}</code>.
154 */
155 STATIC(Modifier.STATIC, true, Location.SET_FIELD_METHOD_INNER_CLASS,
156 new Function<ClassFileFormatVersion, Set<Location>>() {
157 @Override
158 public Set<Location> apply(ClassFileFormatVersion cffv) {
159 return (cffv == ClassFileFormatVersion.RELEASE_0) ?
160 Location.SET_FIELD_METHOD:
161 Location.SET_FIELD_METHOD_INNER_CLASS;}
162 }),
163
164 /**
165 * The access flag {@code ACC_FINAL}, corresponding to the source
166 * modifier {@link Modifier#FINAL final}, with a mask
167 * value of <code>{@value "0x%04x" Modifier#FINAL}</code>.
168 */
169 FINAL(Modifier.FINAL, true,
170 Location.SET_FINAL_8,
171 new Function<ClassFileFormatVersion, Set<Location>>() {
172 @Override
173 public Set<Location> apply(ClassFileFormatVersion cffv) {
174 if (cffv.compareTo(ClassFileFormatVersion.RELEASE_8) >= 0) {
175 return Location.SET_FINAL_8;
176 } else {
177 return (cffv == ClassFileFormatVersion.RELEASE_0) ?
178 Location.SET_CLASS_FIELD_METHOD :
179 Location.SET_CLASS_FIELD_METHOD_INNER_CLASS;
180 }
181 }
182 }),
183
184 /**
185 * The access flag {@code ACC_SUPER} with a mask value of {@code
186 * 0x0020}.
187 *
188 * @apiNote
189 * In Java SE 8 and above, the JVM treats the {@code ACC_SUPER}
190 * flag as set in every class file (JVMS {@jvms 4.1}).
191 * If preview feature is enabled,
192 * the {@code 0x0020} access flag bit is {@linkplain #IDENTITY IDENTITY access flag}.
193 */
194 SUPER(0x0000_0020, false,
195 PreviewFeatures.isEnabled() ? Location.EMPTY_SET : Location.SET_CLASS,
196 new Function<ClassFileFormatVersion, Set<Location>>() {
197 @Override
198 public Set<Location> apply(ClassFileFormatVersion cffv) {
199 return (cffv.compareTo(ClassFileFormatVersion.latest()) >= 0) &&
200 PreviewFeatures.isEnabled() ? Location.EMPTY_SET : Location.SET_CLASS;
201 }
202 }),
203
204 /**
205 * The access flag {@code ACC_IDENTITY}, corresponding to the
206 * modifier {@link Modifier#IDENTITY identity}, with a mask
207 * value of <code>{@value "0x%04x" Modifier#IDENTITY}</code>.
208 * @jvms 4.1 -B. Class access and property modifiers
209 *
210 * @since Valhalla
211 */
212 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
213 IDENTITY(Modifier.IDENTITY, false,
214 PreviewFeatures.isEnabled() ? Location.SET_CLASS_INNER_CLASS : Location.EMPTY_SET,
215 new Function<ClassFileFormatVersion, Set<Location>>() {
216 @Override
217 public Set<Location> apply(ClassFileFormatVersion cffv) {
218 return (cffv.compareTo(ClassFileFormatVersion.latest()) >= 0
219 && PreviewFeatures.isEnabled())
220 ? Location.SET_CLASS_INNER_CLASS : Location.EMPTY_SET;
221 }
222 }),
223
224 /**
225 * The module flag {@code ACC_OPEN} with a mask value of {@code
226 * 0x0020}.
227 * @see java.lang.module.ModuleDescriptor#isOpen
228 */
229 OPEN(0x0000_0020, false, Location.SET_MODULE,
230 new Function<ClassFileFormatVersion, Set<Location>>() {
231 @Override
232 public Set<Location> apply(ClassFileFormatVersion cffv) {
233 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 ) ?
234 Location.SET_MODULE:
235 Location.EMPTY_SET;}
236 }),
237
238 /**
239 * The module requires flag {@code ACC_TRANSITIVE} with a mask
240 * value of {@code 0x0020}.
241 * @see java.lang.module.ModuleDescriptor.Requires.Modifier#TRANSITIVE
242 */
243 TRANSITIVE(0x0000_0020, false, Location.SET_MODULE_REQUIRES,
244 new Function<ClassFileFormatVersion, Set<Location>>() {
245 @Override
246 public Set<Location> apply(ClassFileFormatVersion cffv) {
247 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 ) ?
248 Location.SET_MODULE_REQUIRES:
249 Location.EMPTY_SET;}
250 }),
251
252 /**
253 * The access flag {@code ACC_SYNCHRONIZED}, corresponding to the
254 * source modifier {@link Modifier#SYNCHRONIZED synchronized}, with
255 * a mask value of <code>{@value "0x%04x" Modifier#SYNCHRONIZED}</code>.
256 */
257 SYNCHRONIZED(Modifier.SYNCHRONIZED, true, Location.SET_METHOD, null),
258
259 /**
260 * The module requires flag {@code ACC_STATIC_PHASE} with a mask
261 * value of {@code 0x0040}.
262 * @see java.lang.module.ModuleDescriptor.Requires.Modifier#STATIC
263 */
264 STATIC_PHASE(0x0000_0040, false, Location.SET_MODULE_REQUIRES,
265 new Function<ClassFileFormatVersion, Set<Location>>() {
266 @Override
267 public Set<Location> apply(ClassFileFormatVersion cffv) {
268 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 ) ?
269 Location.SET_MODULE_REQUIRES:
270 Location.EMPTY_SET;}
271 }),
272
273 /**
274 * The access flag {@code ACC_VOLATILE}, corresponding to the
275 * source modifier {@link Modifier#VOLATILE volatile}, with a mask
276 * value of <code>{@value "0x%04x" Modifier#VOLATILE}</code>.
277 */
278 VOLATILE(Modifier.VOLATILE, true, Location.SET_FIELD, null),
279
280 /**
281 * The access flag {@code ACC_BRIDGE} with a mask value of
282 * <code>{@value "0x%04x" Modifier#BRIDGE}</code>
283 * @see Method#isBridge()
284 */
285 BRIDGE(Modifier.BRIDGE, false, Location.SET_METHOD,
286 new Function<ClassFileFormatVersion, Set<Location>>() {
287 @Override
288 public Set<Location> apply(ClassFileFormatVersion cffv) {
289 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_5) >= 0 ) ?
290 Location.SET_METHOD:
291 Location.EMPTY_SET;}
292 }),
293
294 /**
295 * The access flag {@code ACC_TRANSIENT}, corresponding to the
296 * source modifier {@link Modifier#TRANSIENT transient}, with a
297 * mask value of <code>{@value "0x%04x" Modifier#TRANSIENT}</code>.
298 */
299 TRANSIENT(Modifier.TRANSIENT, true, Location.SET_FIELD, null),
300
301 /**
302 * The access flag {@code ACC_VARARGS} with a mask value of
303 <code>{@value "0x%04x" Modifier#VARARGS}</code>.
304 * @see Executable#isVarArgs()
305 */
306 VARARGS(Modifier.VARARGS, false, Location.SET_METHOD,
307 new Function<ClassFileFormatVersion, Set<Location>>() {
308 @Override
309 public Set<Location> apply(ClassFileFormatVersion cffv) {
310 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_5) >= 0 ) ?
311 Location.SET_METHOD:
312 Location.EMPTY_SET;}
313 }),
314
315 /**
316 * The access flag {@code ACC_NATIVE}, corresponding to the source
317 * modifier {@link Modifier#NATIVE native}, with a mask value of
318 * <code>{@value "0x%04x" Modifier#NATIVE}</code>.
319 */
320 NATIVE(Modifier.NATIVE, true, Location.SET_METHOD, null),
321
322 /**
323 * The access flag {@code ACC_INTERFACE} with a mask value of
324 * {@code 0x0200}.
325 * @see Class#isInterface()
326 */
327 INTERFACE(Modifier.INTERFACE, false, Location.SET_CLASS_INNER_CLASS,
328 new Function<ClassFileFormatVersion, Set<Location>>() {
329 @Override
330 public Set<Location> apply(ClassFileFormatVersion cffv) {
331 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_0) == 0 ) ?
332 Location.SET_CLASS:
333 Location.SET_CLASS_INNER_CLASS;}
334 }),
335
336 /**
337 * The access flag {@code ACC_ABSTRACT}, corresponding to the
338 * source modifier {@link Modifier#ABSTRACT abstract}, with a mask
339 * value of <code>{@value "0x%04x" Modifier#ABSTRACT}</code>.
340 */
341 ABSTRACT(Modifier.ABSTRACT, true,
342 Location.SET_CLASS_METHOD_INNER_CLASS,
343 new Function<ClassFileFormatVersion, Set<Location>>() {
344 @Override
345 public Set<Location> apply(ClassFileFormatVersion cffv) {
346 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_0) == 0 ) ?
347 Location.SET_CLASS_METHOD:
348 Location.SET_CLASS_METHOD_INNER_CLASS;}
349 }),
350
351 /**
352 * The access flag {@code ACC_STRICT}, corresponding to the source
353 * modifier {@link Modifier#STRICT strictfp}, with a mask value of
354 * <code>{@value "0x%04x" Modifier#STRICT}</code>.
355 *
356 * @apiNote
357 * The {@code ACC_STRICT} access flag is defined for class file
358 * major versions 46 through 60, inclusive (JVMS {@jvms 4.6}),
359 * corresponding to Java SE 1.2 through 16.
360 */
361 STRICT(Modifier.STRICT, true, Location.EMPTY_SET,
362 new Function<ClassFileFormatVersion, Set<Location>>() {
363 @Override
364 public Set<Location> apply(ClassFileFormatVersion cffv) {
365 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_2) >= 0 &&
366 cffv.compareTo(ClassFileFormatVersion.RELEASE_16) <= 0) ?
367 Location.SET_METHOD:
368 Location.EMPTY_SET;}
369 }),
370
371 /**
372 * The access flag {@code ACC_STRICT_INIT}, with a mask
373 * value of {@code 0x0800}.
374 *
375 * @jvms 4.5 Fields
376 * @since Valhalla
377 */
378 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
379 STRICT_INIT(Modifier.STRICT, false,
380 PreviewFeatures.isEnabled() ? Location.SET_FIELD : Location.EMPTY_SET,
381 new Function<ClassFileFormatVersion, Set<Location>>() {
382 @Override
383 public Set<Location> apply(ClassFileFormatVersion cffv) {
384 return (cffv.compareTo(ClassFileFormatVersion.latest()) >= 0
385 && PreviewFeatures.isEnabled())
386 ? Location.SET_FIELD : Location.EMPTY_SET;
387 }
388 }),
389
390 /**
391 * The access flag {@code ACC_SYNTHETIC} with a mask value of
392 * <code>{@value "0x%04x" Modifier#SYNTHETIC}</code>.
393 * @see Class#isSynthetic()
394 * @see Executable#isSynthetic()
395 * @see java.lang.module.ModuleDescriptor.Modifier#SYNTHETIC
396 */
397 SYNTHETIC(Modifier.SYNTHETIC, false, Location.SET_SYNTHETIC_9,
398 new Function<ClassFileFormatVersion, Set<Location>>() {
399 @Override
400 public Set<Location> apply(ClassFileFormatVersion cffv) {
401 if (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 )
402 return Location.SET_SYNTHETIC_9;
403 else {
404 return
405 switch(cffv) {
406 case RELEASE_7 -> Location.SET_SYNTHETIC_7;
407 case RELEASE_8 -> Location.SET_SYNTHETIC_8;
408 default -> Location.EMPTY_SET;
409 };
410 }
411 }
412 }),
413
414 /**
415 * The access flag {@code ACC_ANNOTATION} with a mask value of
416 * <code>{@value "0x%04x" Modifier#ANNOTATION}</code>.
417 * @see Class#isAnnotation()
418 */
419 ANNOTATION(Modifier.ANNOTATION, false, Location.SET_CLASS_INNER_CLASS,
420 new Function<ClassFileFormatVersion, Set<Location>>() {
421 @Override
422 public Set<Location> apply(ClassFileFormatVersion cffv) {
423 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_5) >= 0 ) ?
424 Location.SET_CLASS_INNER_CLASS:
425 Location.EMPTY_SET;}
426 }),
427
428 /**
429 * The access flag {@code ACC_ENUM} with a mask value of
430 * <code>{@value "0x%04x" Modifier#ENUM}</code>.
431 * @see Class#isEnum()
432 */
433 ENUM(Modifier.ENUM, false, Location.SET_CLASS_FIELD_INNER_CLASS,
434 new Function<ClassFileFormatVersion, Set<Location>>() {
435 @Override
436 public Set<Location> apply(ClassFileFormatVersion cffv) {
437 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_5) >= 0 ) ?
438 Location.SET_CLASS_FIELD_INNER_CLASS:
439 Location.EMPTY_SET;}
440 }),
441
442 /**
443 * The access flag {@code ACC_MANDATED} with a mask value of
444 * <code>{@value "0x%04x" Modifier#MANDATED}</code>.
445 */
446 MANDATED(Modifier.MANDATED, false, Location.SET_MANDATED_9,
447 new Function<ClassFileFormatVersion, Set<Location>>() {
448 @Override
449 public Set<Location> apply(ClassFileFormatVersion cffv) {
450 if (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 ) {
451 return Location.SET_MANDATED_9;
452 } else {
453 return (cffv == ClassFileFormatVersion.RELEASE_8) ?
454 Location.SET_METHOD_PARAM:
455 Location.EMPTY_SET;
456 }
457 }
458 }),
459
460 /**
461 * The access flag {@code ACC_MODULE} with a mask value of {@code
462 * 0x8000}.
463 */
464 MODULE(0x0000_8000, false, Location.SET_CLASS,
465 new Function<ClassFileFormatVersion, Set<Location>>() {
466 @Override
467 public Set<Location> apply(ClassFileFormatVersion cffv) {
468 return (cffv.compareTo(ClassFileFormatVersion.RELEASE_9) >= 0 ) ?
469 Location.SET_CLASS:
470 Location.EMPTY_SET;}
471 })
472 ;
473
474 // May want to override toString for a different enum constant ->
475 // name mapping.
476
477 private final int mask;
478 private final boolean sourceModifier;
479
480 // Intentionally using Set rather than EnumSet since EnumSet is
481 // mutable.
482 private final Set<Location> locations;
483 // Lambda to implement locations(ClassFileFormatVersion cffv)
484 private final Function<ClassFileFormatVersion, Set<Location>> cffvToLocations;
485
486 private AccessFlag(int mask,
487 boolean sourceModifier,
488 Set<Location> locations,
489 Function<ClassFileFormatVersion, Set<Location>> cffvToLocations) {
490 this.mask = mask;
491 this.sourceModifier = sourceModifier;
492 this.locations = locations;
493 this.cffvToLocations = cffvToLocations;
494 }
495
496 /**
497 * {@return the corresponding integer mask for the access flag}
498 */
499 public int mask() {
500 return mask;
501 }
502
503 /**
504 * {@return whether or not the flag has a directly corresponding
505 * modifier in the Java programming language}
506 */
507 public boolean sourceModifier() {
508 return sourceModifier;
509 }
510
511 /**
512 * {@return kinds of constructs the flag can be applied to in the
513 * latest class file format version}
514 */
515 public Set<Location> locations() {
516 return locations;
517 }
518
519 /**
520 * {@return kinds of constructs the flag can be applied to in the
521 * given class file format version}
522 * @param cffv the class file format version to use
523 * @throws NullPointerException if the parameter is {@code null}
524 */
525 public Set<Location> locations(ClassFileFormatVersion cffv) {
526 Objects.requireNonNull(cffv);
527 if (cffvToLocations == null) {
528 return locations;
529 } else {
530 return cffvToLocations.apply(cffv);
531 }
532 }
533
534 /**
535 * {@return an unmodifiable set of access flags for the given mask value
536 * appropriate for the location in question}
537 *
538 * @param mask bit mask of access flags
539 * @param location context to interpret mask value
540 * @throws IllegalArgumentException if the mask contains bit
541 * positions not supported for the location in question
542 */
543 public static Set<AccessFlag> maskToAccessFlags(int mask, Location location) {
544 Set<AccessFlag> result = java.util.EnumSet.noneOf(AccessFlag.class);
545 for (var accessFlag : LocationToFlags.locationToFlags.get(location)) {
546 int accessMask = accessFlag.mask();
547 if ((mask & accessMask) != 0) {
548 result.add(accessFlag);
549 mask = mask & ~accessMask;
550 if (mask == 0) {
551 break; // no more mask bits
552 }
553 }
554 }
555 if (mask != 0) {
556 throw new IllegalArgumentException("Unmatched bit position 0x" +
557 Integer.toHexString(mask) +
558 " for location " + location);
559 }
560 return Collections.unmodifiableSet(result);
561 }
562
563 /**
564 * {@return an unmodifiable set of access flags for the given mask value
565 * appropriate for the location in question}
566 *
567 * @param mask bit mask of access flags
568 * @param location context to interpret mask value
569 * @param cffv the class file format version
570 * @throws IllegalArgumentException if the mask contains bit
571 * positions not supported for the location in question
572 *
573 * @since Valhalla
574 */
575 public static Set<AccessFlag> maskToAccessFlags(int mask, Location location,
576 ClassFileFormatVersion cffv) {
577 Set<AccessFlag> result = java.util.EnumSet.noneOf(AccessFlag.class);
578 for (var accessFlag : AccessFlag.values()) {
579 int accessMask = accessFlag.mask();
580 if ((mask & accessMask) != 0) {
581 var locations = accessFlag.locations(cffv);
582 if (locations.contains(location)) {
583 result.add(accessFlag);
584 mask = mask & ~accessMask;
585 if (mask == 0) {
586 break; // no more mask bits
587 }
588 }
589 }
590 }
591 if (mask != 0) {
592 throw new IllegalArgumentException("Unmatched bit position 0x" +
593 Integer.toHexString(mask) +
594 " for location " + location +
595 " for class file format version " + cffv);
596 }
597 return Collections.unmodifiableSet(result);
598 }
599
600
601 /**
602 * A location within a class file where flags can be applied.
603 *
604 * Note that since these locations represent class file structures
605 * rather than language structures many language structures, such
606 * as constructors and interfaces, are <em>not</em> present.
607 * @since 20
608 */
609 public enum Location {
610 /**
611 * Class location.
612 * @jvms 4.1 The ClassFile Structure
613 */
614 CLASS,
615
616 /**
617 * Field location.
618 * @jvms 4.5 Fields
619 */
620 FIELD,
621
622 /**
623 * Method location.
624 * @jvms 4.6 Methods
625 */
626 METHOD,
627
628 /**
629 * Inner class location.
630 * @jvms 4.7.6 The InnerClasses Attribute
631 */
632 INNER_CLASS,
633
634 /**
635 * Method parameter location.
636 * @jvms 4.7.24 The MethodParameters Attribute
637 */
638 METHOD_PARAMETER,
639
640 /**
641 * Module location
642 * @jvms 4.7.25 The Module Attribute
643 */
644 MODULE,
645
646 /**
647 * Module requires location
648 * @jvms 4.7.25 The Module Attribute
649 */
650 MODULE_REQUIRES,
651
652 /**
653 * Module exports location
654 * @jvms 4.7.25 The Module Attribute
655 */
656 MODULE_EXPORTS,
657
658 /**
659 * Module opens location
660 * @jvms 4.7.25 The Module Attribute
661 */
662 MODULE_OPENS;
663
664 // Repeated sets of locations used by AccessFlag constants
665 private static final Set<Location> EMPTY_SET = Set.of();
666 private static final Set<Location> SET_MODULE = Set.of(MODULE);
667 private static final Set<Location> SET_CLASS_METHOD_INNER_CLASS =
668 Set.of(CLASS, METHOD, INNER_CLASS);
669 private static final Set<Location> SET_CLASS_FIELD_METHOD =
670 Set.of(CLASS, FIELD, METHOD);
671 private static final Set<Location> SET_CLASS_FIELD_INNER_CLASS =
672 Set.of(CLASS, FIELD, INNER_CLASS);
673 private static final Set<Location> SET_CLASS_FIELD_METHOD_INNER_CLASS =
674 Set.of(CLASS, FIELD, METHOD, INNER_CLASS);
675 private static final Set<Location> SET_CLASS_METHOD =
676 Set.of(CLASS, METHOD);
677 private static final Set<Location> SET_FIELD_METHOD =
678 Set.of(FIELD, METHOD);
679 private static final Set<Location> SET_FIELD_METHOD_INNER_CLASS =
680 Set.of(FIELD, METHOD, INNER_CLASS);
681 private static final Set<Location> SET_METHOD = Set.of(METHOD);
682 private static final Set<Location> SET_METHOD_PARAM = Set.of(METHOD_PARAMETER);
683 private static final Set<Location> SET_FIELD = Set.of(FIELD);
684 private static final Set<Location> SET_CLASS = Set.of(CLASS);
685 private static final Set<Location> SET_CLASS_INNER_CLASS =
686 Set.of(CLASS, INNER_CLASS);
687 private static final Set<Location> SET_MODULE_REQUIRES =
688 Set.of(MODULE_REQUIRES);
689 private static final Set<Location> SET_PUBLIC_1 =
690 Set.of(CLASS, FIELD, METHOD, INNER_CLASS);
691 private static final Set<Location> SET_FINAL_8 =
692 Set.of(CLASS, FIELD, METHOD,
693 INNER_CLASS, /* added in 1.1 */
694 METHOD_PARAMETER); /* added in 8 */
695 private static final Set<Location> SET_SYNTHETIC_7 =
696 Set.of(CLASS, FIELD, METHOD,
697 INNER_CLASS);
698 private static final Set<Location> SET_SYNTHETIC_8 =
699 Set.of(CLASS, FIELD, METHOD,
700 INNER_CLASS, METHOD_PARAMETER);
701 private static final Set<Location> SET_SYNTHETIC_9 =
702 // Added as an access flag in 7
703 Set.of(CLASS, FIELD, METHOD,
704 INNER_CLASS,
705 METHOD_PARAMETER, // Added in 8
706 // Module-related items added in 9
707 MODULE, MODULE_REQUIRES,
708 MODULE_EXPORTS, MODULE_OPENS);
709 private static final Set<Location> SET_MANDATED_9 =
710 Set.of(METHOD_PARAMETER, // From 8
711 // Starting in 9
712 MODULE, MODULE_REQUIRES,
713 MODULE_EXPORTS, MODULE_OPENS);
714 }
715
716 private static class LocationToFlags {
717 private static Map<Location, Set<AccessFlag>> locationToFlags =
718 Map.ofEntries(entry(Location.CLASS,
719 Set.of(PUBLIC, FINAL, (PreviewFeatures.isEnabled() ? IDENTITY : SUPER),
720 INTERFACE, ABSTRACT,
721 SYNTHETIC, ANNOTATION,
722 ENUM, AccessFlag.MODULE)),
723 entry(Location.FIELD,
724 PreviewFeatures.isEnabled() ?
725 // STRICT_INIT should be included only if preview is enabled
726 Set.of(PUBLIC, PRIVATE, PROTECTED,
727 STATIC, FINAL, VOLATILE,
728 TRANSIENT, SYNTHETIC, ENUM, STRICT_INIT) :
729 Set.of(PUBLIC, PRIVATE, PROTECTED,
730 STATIC, FINAL, VOLATILE,
731 TRANSIENT, SYNTHETIC, ENUM)),
732 entry(Location.METHOD,
733 Set.of(PUBLIC, PRIVATE, PROTECTED,
734 STATIC, FINAL, SYNCHRONIZED,
735 BRIDGE, VARARGS, NATIVE,
736 ABSTRACT, STRICT, SYNTHETIC)),
737 entry(Location.INNER_CLASS,
738 Set.of(PUBLIC, PRIVATE, PROTECTED, (PreviewFeatures.isEnabled() ? IDENTITY : SUPER),
739 STATIC, FINAL, INTERFACE, ABSTRACT,
740 SYNTHETIC, ANNOTATION, ENUM)),
741 entry(Location.METHOD_PARAMETER,
742 Set.of(FINAL, SYNTHETIC, MANDATED)),
743 entry(Location.MODULE,
744 Set.of(OPEN, SYNTHETIC, MANDATED)),
745 entry(Location.MODULE_REQUIRES,
746 Set.of(TRANSITIVE, STATIC_PHASE, SYNTHETIC, MANDATED)),
747 entry(Location.MODULE_EXPORTS,
748 Set.of(SYNTHETIC, MANDATED)),
749 entry(Location.MODULE_OPENS,
750 Set.of(SYNTHETIC, MANDATED)));
751 }
752 }