< prev index next >

src/java.base/share/classes/java/lang/reflect/AccessFlag.java

Print this page

  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.lang.classfile.ClassModel;
 29 import java.lang.classfile.FieldModel;
 30 import java.lang.classfile.MethodModel;
 31 import java.lang.classfile.attribute.InnerClassInfo;
 32 import java.lang.classfile.attribute.MethodParameterInfo;
 33 import java.lang.classfile.attribute.ModuleAttribute;
 34 import java.lang.classfile.attribute.ModuleExportInfo;
 35 import java.lang.classfile.attribute.ModuleOpenInfo;
 36 import java.lang.classfile.attribute.ModuleRequireInfo;
 37 import java.lang.module.ModuleDescriptor;
 38 import java.util.AbstractSet;
 39 import java.util.Collection;
 40 import java.util.Iterator;
 41 import java.util.List;
 42 import java.util.Map;
 43 import java.util.NoSuchElementException;
 44 import java.util.Objects;
 45 import java.util.Set;
 46 import java.util.function.Consumer;
 47 import java.util.function.Predicate;

145     STATIC(Modifier.STATIC, true, Location.SET_FIELD_METHOD_INNER_CLASS,
146            List.of(Map.entry(RELEASE_0, Location.SET_FIELD_METHOD))),
147 
148     /**
149      * The access flag {@code ACC_FINAL}, corresponding to the source
150      * modifier {@link Modifier#FINAL final}, with a mask
151      * value of <code>{@value "0x%04x" Modifier#FINAL}</code>.
152      */
153     FINAL(Modifier.FINAL, true,
154           Location.SET_FINAL_8,
155           List.of(Map.entry(RELEASE_7, Location.SET_CLASS_FIELD_METHOD_INNER_CLASS),
156                   Map.entry(RELEASE_0, Location.SET_CLASS_FIELD_METHOD))),
157 
158     /**
159      * The access flag {@code ACC_SUPER} with a mask value of {@code
160      * 0x0020}.
161      *
162      * @apiNote
163      * In Java SE 8 and above, the JVM treats the {@code ACC_SUPER}
164      * flag as set in every class file (JVMS {@jvms 4.1}).














165      */
166     SUPER(0x0000_0020, false, Location.SET_CLASS, List.of()),



167 
168     /**
169      * The module flag {@code ACC_OPEN} with a mask value of {@code
170      * 0x0020}.
171      * @see java.lang.module.ModuleDescriptor#isOpen
172      */
173     OPEN(0x0000_0020, false, Location.SET_MODULE,
174          List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
175 
176     /**
177      * The module requires flag {@code ACC_TRANSITIVE} with a mask
178      * value of {@code 0x0020}.
179      * @see java.lang.module.ModuleDescriptor.Requires.Modifier#TRANSITIVE
180      */
181     TRANSITIVE(0x0000_0020, false, Location.SET_MODULE_REQUIRES,
182                List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
183 
184     /**
185      * The access flag {@code ACC_SYNCHRONIZED}, corresponding to the
186      * source modifier {@link Modifier#SYNCHRONIZED synchronized}, with

247      * value of <code>{@value "0x%04x" Modifier#ABSTRACT}</code>.
248      */
249     ABSTRACT(Modifier.ABSTRACT, true,
250              Location.SET_CLASS_METHOD_INNER_CLASS,
251              List.of(Map.entry(RELEASE_0, Location.SET_CLASS_METHOD))),
252 
253     /**
254      * The access flag {@code ACC_STRICT}, corresponding to the source
255      * modifier {@link Modifier#STRICT strictfp}, with a mask value of
256      * <code>{@value "0x%04x" Modifier#STRICT}</code>.
257      *
258      * @apiNote
259      * The {@code ACC_STRICT} access flag is defined for class file
260      * major versions 46 through 60, inclusive (JVMS {@jvms 4.6}),
261      * corresponding to Java SE 1.2 through 16.
262      */
263     STRICT(Modifier.STRICT, true, Location.EMPTY_SET,
264            List.of(Map.entry(RELEASE_16, Location.SET_METHOD),
265                    Map.entry(RELEASE_1, Location.EMPTY_SET))),
266 












267     /**
268      * The access flag {@code ACC_SYNTHETIC} with a mask value of
269      * <code>{@value "0x%04x" Modifier#SYNTHETIC}</code>.
270      * @see Class#isSynthetic()
271      * @see Executable#isSynthetic()
272      * @see java.lang.module.ModuleDescriptor.Modifier#SYNTHETIC
273      */
274     SYNTHETIC(Modifier.SYNTHETIC, false, Location.SET_SYNTHETIC_9,
275               List.of(Map.entry(RELEASE_8, Location.SET_SYNTHETIC_8),
276                       Map.entry(RELEASE_7, Location.SET_SYNTHETIC_5),
277                       Map.entry(RELEASE_4, Location.EMPTY_SET))),
278 
279     /**
280      * The access flag {@code ACC_ANNOTATION} with a mask value of
281      * <code>{@value "0x%04x" Modifier#ANNOTATION}</code>.
282      * @see Class#isAnnotation()
283      */
284     ANNOTATION(Modifier.ANNOTATION, false, Location.SET_CLASS_INNER_CLASS,
285                List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
286 

336     public int mask() {
337         return mask;
338     }
339 
340     /**
341      * {@return whether or not this flag has a directly corresponding
342      * modifier in the Java programming language}
343      */
344     public boolean sourceModifier() {
345         return sourceModifier;
346     }
347 
348     /**
349      * {@return locations this flag can be applied to in the current class file
350      * format version}
351      * <p>
352      * This method returns an empty set if this flag is not defined in
353      * the current class file format version.
354      */
355     public Set<Location> locations() {
356         return locations;
357     }
358 
359     /**
360      * {@return locations this flag can be applied to in the given class file
361      * format version}
362      * <p>
363      * This method returns an empty set if this flag is not defined in
364      * the given {@code cffv}.
365      *
366      * @param cffv the class file format version to use
367      * @throws NullPointerException if the parameter is {@code null}
368      */
369     public Set<Location> locations(ClassFileFormatVersion cffv) {
370         return Location.findInHistory(locations, historicalLocations, cffv);
371     }
372 
373     /**
374      * {@return an unmodifiable set of access flags for the given mask value
375      * appropriate for the location in the current class file format version}
376      *
377      * @param mask bit mask of access flags
378      * @param location context to interpret mask value
379      * @throws IllegalArgumentException if the mask contains bit
380      * positions not defined for the location in the current class file format
381      * @throws NullPointerException if {@code location} is {@code null}
382      */
383     public static Set<AccessFlag> maskToAccessFlags(int mask, Location location) {
384         var definition = findDefinition(location);  // null checks location
385         int unmatchedMask = mask & (~location.flagsMask());
386         if (unmatchedMask != 0) {
387             throw new IllegalArgumentException("Unmatched bit position 0x" +
388                     Integer.toHexString(unmatchedMask) +
389                     " for location " + location);
390         }
391         return new AccessFlagSet(definition, mask);
392     }
393 
394     /**
395      * {@return an unmodifiable set of access flags for the given mask value
396      * appropriate for the location in the given class file format version}
397      *
398      * @param mask bit mask of access flags
399      * @param location context to interpret mask value
400      * @param cffv the class file format to interpret mask value
401      * @throws IllegalArgumentException if the mask contains bit
402      * positions not defined for the location in the given class file format
403      * @throws NullPointerException if {@code location} or {@code cffv} is {@code null}
404      * @since 25
405      */
406     public static Set<AccessFlag> maskToAccessFlags(int mask, Location location, ClassFileFormatVersion cffv) {
407         var definition = findDefinition(location);  // null checks location
408         int unmatchedMask = mask & (~location.flagsMask(cffv));  // null checks cffv
409         if (unmatchedMask != 0) {
410             throw new IllegalArgumentException("Unmatched bit position 0x" +
411                     Integer.toHexString(unmatchedMask) +
412                     " for location " + location +
413                     " for class file format " + cffv);
414         }
415         return new AccessFlagSet(definition, mask);
416     }
417 
418     /**
419      * A location within a {@code class} file where flags can be applied.
420      * <p>
421      * Note that since these locations represent {@code class} file structures
422      * rather than language structures, many language structures, such
423      * as constructors and interfaces, are <em>not</em> present.
424      * @since 20
425      */
426     public enum Location {
427         /**
428          * Class location.
429          *
430          * @see Class#accessFlags()
431          * @see ClassModel#flags()
432          * @see Modifier#classModifiers()
433          * @see Modifier#interfaceModifiers()
434          * @jvms 4.1 The {@code ClassFile} Structure
435          */
436         CLASS(ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
437               ACC_INTERFACE | ACC_ABSTRACT |
438               ACC_SYNTHETIC | ACC_ANNOTATION |
439               ACC_ENUM | ACC_MODULE,
440               List.of(Map.entry(RELEASE_8, // no module
441                                 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
442                                 ACC_INTERFACE | ACC_ABSTRACT |
443                                 ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM),
444                       Map.entry(RELEASE_4, // no synthetic, annotation, enum
445                                 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
446                                 ACC_INTERFACE | ACC_ABSTRACT))),
447 
448         /**
449          * Field location.
450          *
451          * @see Field#accessFlags()
452          * @see FieldModel#flags()
453          * @see Modifier#fieldModifiers()
454          * @jvms 4.5 Fields
455          */
456         FIELD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
457               ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
458               ACC_TRANSIENT | ACC_SYNTHETIC | ACC_ENUM,
459               List.of(Map.entry(RELEASE_4, // no synthetic, enum




460                                 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
461                                 ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
462                                 ACC_TRANSIENT))),
463 
464         /**
465          * Method location.
466          *
467          * @see Executable#accessFlags()
468          * @see MethodModel#flags()
469          * @see Modifier#methodModifiers()
470          * @see Modifier#constructorModifiers()
471          * @jvms 4.6 Methods
472          */
473         METHOD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
474                ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
475                ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
476                ACC_ABSTRACT | ACC_SYNTHETIC,
477                List.of(Map.entry(RELEASE_16, // had strict
478                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
479                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
480                                  ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
481                                  ACC_ABSTRACT | ACC_STRICT | ACC_SYNTHETIC),
482                        Map.entry(RELEASE_4, // no bridge, varargs, synthetic
483                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
484                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
485                                  ACC_NATIVE | ACC_ABSTRACT | ACC_STRICT),
486                        Map.entry(RELEASE_1, // no strict
487                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
488                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
489                                  ACC_NATIVE | ACC_ABSTRACT))),
490 
491         /**
492          * Inner class location.
493          *
494          * @see Class#accessFlags()
495          * @see InnerClassInfo#flags()
496          * @see Modifier#classModifiers()
497          * @see Modifier#interfaceModifiers()
498          * @jvms 4.7.6 The {@code InnerClasses} Attribute
499          */
500         INNER_CLASS(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
501                     ACC_STATIC | ACC_FINAL | ACC_INTERFACE | ACC_ABSTRACT |
502                     ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM,
503                     List.of(Map.entry(RELEASE_4, // no synthetic, annotation, enum
504                             ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
505                             ACC_STATIC | ACC_FINAL | ACC_INTERFACE |
506                             ACC_ABSTRACT),




507                             Map.entry(RELEASE_0, 0))), // did not exist
508 
509         /**
510          * Method parameter location.
511          *
512          * @see Parameter#accessFlags()
513          * @see MethodParameterInfo#flags()
514          * @see Modifier#parameterModifiers()
515          * @jvms 4.7.24 The {@code MethodParameters} Attribute
516          */
517         METHOD_PARAMETER(ACC_FINAL | ACC_SYNTHETIC | ACC_MANDATED,
518                          List.of(Map.entry(RELEASE_7, 0))),  // did not exist
519 
520         /**
521          * Module location.
522          *
523          * @see ModuleDescriptor#accessFlags()
524          * @see ModuleAttribute#moduleFlags()
525          * @jvms 4.7.25 The {@code Module} Attribute
526          */

603                      MODULE_EXPORTS, MODULE_OPENS);
604         private static final Set<Location> SET_MANDATED_9 =
605             Set.of(METHOD_PARAMETER, // From 8
606                    // Starting in 9
607                    MODULE, MODULE_REQUIRES,
608                    MODULE_EXPORTS, MODULE_OPENS);
609 
610         private final int flagsMask;
611         private final List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks;
612 
613         Location(int flagsMask,
614                  List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks) {
615             this.flagsMask = flagsMask;
616             this.historicalFlagsMasks = ensureHistoryOrdered(historicalFlagsMasks);
617         }
618 
619         // Ensures the historical versions are from newest to oldest and do not include the latest
620         // These 2 utilities reside in Location because Location must be initialized before AccessFlag
621         private static <T> List<Map.Entry<ClassFileFormatVersion, T>> ensureHistoryOrdered(
622                 List<Map.Entry<ClassFileFormatVersion, T>> history) {
623             ClassFileFormatVersion lastVersion = ClassFileFormatVersion.latest();
624             for (var e : history) {
625                 var historyVersion = e.getKey();
626                 if (lastVersion.compareTo(historyVersion) <= 0) {
627                     throw new IllegalArgumentException("Versions out of order");
628                 }
629                 lastVersion = historyVersion;
630             }
631             return history;
632         }
633 
634         private static <T> T findInHistory(T candidate, List<Map.Entry<ClassFileFormatVersion, T>> history,
635                                            ClassFileFormatVersion cffv) {
636             Objects.requireNonNull(cffv);
637             for (var e : history) {
638                 if (e.getKey().compareTo(cffv) < 0) {
639                     // last version found was valid
640                     return candidate;
641                 }
642                 candidate = e.getValue();
643             }
644             return candidate;
645         }
646 
647         /**
648          * {@return the union of masks of all access flags defined for
649          * this location in the current class file format version}
650          * <p>
651          * This method returns {@code 0} if this location does not exist in
652          * the current class file format version.
653          *
654          * @since 25
655          */
656         public int flagsMask() {
657             return flagsMask;
658         }
659 
660         /**
661          * {@return the union of masks of all access flags defined for
662          * this location in the given class file format version}
663          * <p>
664          * This method returns {@code 0} if this location does not exist in
665          * the given {@code cffv}.
666          *
667          * @param cffv the class file format version
668          * @throws NullPointerException if {@code cffv} is {@code null}
669          * @since 25
670          */
671         public int flagsMask(ClassFileFormatVersion cffv) {
672             return findInHistory(flagsMask, historicalFlagsMasks, cffv);
673         }
674 
675         /**
676          * {@return the set of access flags defined for this location in the
677          * current class file format version}  The set is immutable.
678          * <p>
679          * This method returns an empty set if this location does not exist
680          * in the current class file format version.
681          *
682          * @since 25
683          */
684         public Set<AccessFlag> flags() {
685             return new AccessFlagSet(findDefinition(this), flagsMask());
686         }
687 
688         /**
689          * {@return the set of access flags defined for this location in the
690          * given class file format version}  The set is immutable.
691          * <p>
692          * This method returns an empty set if this location does not exist
693          * in the given {@code cffv}.
694          *
695          * @param cffv the class file format version
696          * @throws NullPointerException if {@code cffv} is {@code null}
697          * @since 25
698          */
699         public Set<AccessFlag> flags(ClassFileFormatVersion cffv) {
700             // implicit null check cffv
701             return new AccessFlagSet(findDefinition(this), flagsMask(cffv));
702         }
703     }
704 
705     private static AccessFlag[] createDefinition(AccessFlag... known) {
706         var ret = new AccessFlag[Character.SIZE];
707         for (var flag : known) {
708             var mask = flag.mask;
709             int pos = Integer.numberOfTrailingZeros(mask);
710             assert ret[pos] == null : ret[pos] + " " + flag;
711             ret[pos] = flag;
712         }
713         return ret;
714     }
715 
716     // Will take extra args in the future for valhalla switch
717     private static AccessFlag[] findDefinition(Location location) {
718         return switch (location) {
719             case CLASS -> CLASS_FLAGS;
720             case FIELD -> FIELD_FLAGS;
721             case METHOD -> METHOD_FLAGS;
722             case INNER_CLASS -> INNER_CLASS_FLAGS;
723             case METHOD_PARAMETER -> METHOD_PARAMETER_FLAGS;
724             case MODULE -> MODULE_FLAGS;
725             case MODULE_REQUIRES -> MODULE_REQUIRES_FLAGS;
726             case MODULE_EXPORTS -> MODULE_EXPORTS_FLAGS;
727             case MODULE_OPENS -> MODULE_OPENS_FLAGS;
728         };
729     }
730 
731     private static final @Stable AccessFlag[] // Can use stable array and lazy init in the future
732             CLASS_FLAGS = createDefinition(PUBLIC, FINAL, SUPER, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM, MODULE),
733             FIELD_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, VOLATILE, TRANSIENT, SYNTHETIC, ENUM),


734             METHOD_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, SYNCHRONIZED, BRIDGE, VARARGS, NATIVE, ABSTRACT, STRICT, SYNTHETIC),
735             INNER_CLASS_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM),

736             METHOD_PARAMETER_FLAGS = createDefinition(FINAL, SYNTHETIC, MANDATED),
737             MODULE_FLAGS = createDefinition(OPEN, SYNTHETIC, MANDATED),
738             MODULE_REQUIRES_FLAGS = createDefinition(TRANSITIVE, STATIC_PHASE, SYNTHETIC, MANDATED),
739             MODULE_EXPORTS_FLAGS = createDefinition(SYNTHETIC, MANDATED),
740             MODULE_OPENS_FLAGS = createDefinition(SYNTHETIC, MANDATED);
741 
742     private static int undefinedMask(AccessFlag[] definition, int mask) {
743         assert definition.length == Character.SIZE;
744         int definedMask = 0;
745         for (int i = 0; i < Character.SIZE; i++) {
746             if (definition[i] != null) {
747                 definedMask |= 1 << i;
748             }
749         }
750         return mask & ~definedMask;
751     }
752 
753     private static final class AccessFlagSet extends AbstractSet<AccessFlag> {
754         private final @Stable AccessFlag[] definition;
755         private final int mask;

  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 
 30 import java.lang.classfile.ClassModel;
 31 import java.lang.classfile.FieldModel;
 32 import java.lang.classfile.MethodModel;
 33 import java.lang.classfile.attribute.InnerClassInfo;
 34 import java.lang.classfile.attribute.MethodParameterInfo;
 35 import java.lang.classfile.attribute.ModuleAttribute;
 36 import java.lang.classfile.attribute.ModuleExportInfo;
 37 import java.lang.classfile.attribute.ModuleOpenInfo;
 38 import java.lang.classfile.attribute.ModuleRequireInfo;
 39 import java.lang.module.ModuleDescriptor;
 40 import java.util.AbstractSet;
 41 import java.util.Collection;
 42 import java.util.Iterator;
 43 import java.util.List;
 44 import java.util.Map;
 45 import java.util.NoSuchElementException;
 46 import java.util.Objects;
 47 import java.util.Set;
 48 import java.util.function.Consumer;
 49 import java.util.function.Predicate;

147     STATIC(Modifier.STATIC, true, Location.SET_FIELD_METHOD_INNER_CLASS,
148            List.of(Map.entry(RELEASE_0, Location.SET_FIELD_METHOD))),
149 
150     /**
151      * The access flag {@code ACC_FINAL}, corresponding to the source
152      * modifier {@link Modifier#FINAL final}, with a mask
153      * value of <code>{@value "0x%04x" Modifier#FINAL}</code>.
154      */
155     FINAL(Modifier.FINAL, true,
156           Location.SET_FINAL_8,
157           List.of(Map.entry(RELEASE_7, Location.SET_CLASS_FIELD_METHOD_INNER_CLASS),
158                   Map.entry(RELEASE_0, Location.SET_CLASS_FIELD_METHOD))),
159 
160     /**
161      * The access flag {@code ACC_SUPER} with a mask value of {@code
162      * 0x0020}.
163      *
164      * @apiNote
165      * In Java SE 8 and above, the JVM treats the {@code ACC_SUPER}
166      * flag as set in every class file (JVMS {@jvms 4.1}).
167      * If preview feature is enabled,
168      * the {@code 0x0020} access flag bit is {@linkplain #IDENTITY IDENTITY access flag}.
169      */
170     SUPER(0x0000_0020, false,
171           Location.EMPTY_SET,
172           List.of(Map.entry(latest(), Location.SET_CLASS))),
173 
174     /**
175      * The access flag {@code ACC_IDENTITY}, corresponding to the
176      * modifier {@link Modifier#IDENTITY identity}, with a mask
177      * value of <code>{@value "0x%04x" Modifier#IDENTITY}</code>.
178      * @jvms 4.1 -B. Class access and property modifiers
179      *
180      * @since Valhalla
181      */
182     @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
183     IDENTITY(Modifier.IDENTITY, false,
184              Location.SET_CLASS_INNER_CLASS,
185              List.of(Map.entry(latest(), Location.EMPTY_SET))),
186 
187     /**
188      * The module flag {@code ACC_OPEN} with a mask value of {@code
189      * 0x0020}.
190      * @see java.lang.module.ModuleDescriptor#isOpen
191      */
192     OPEN(0x0000_0020, false, Location.SET_MODULE,
193          List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
194 
195     /**
196      * The module requires flag {@code ACC_TRANSITIVE} with a mask
197      * value of {@code 0x0020}.
198      * @see java.lang.module.ModuleDescriptor.Requires.Modifier#TRANSITIVE
199      */
200     TRANSITIVE(0x0000_0020, false, Location.SET_MODULE_REQUIRES,
201                List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
202 
203     /**
204      * The access flag {@code ACC_SYNCHRONIZED}, corresponding to the
205      * source modifier {@link Modifier#SYNCHRONIZED synchronized}, with

266      * value of <code>{@value "0x%04x" Modifier#ABSTRACT}</code>.
267      */
268     ABSTRACT(Modifier.ABSTRACT, true,
269              Location.SET_CLASS_METHOD_INNER_CLASS,
270              List.of(Map.entry(RELEASE_0, Location.SET_CLASS_METHOD))),
271 
272     /**
273      * The access flag {@code ACC_STRICT}, corresponding to the source
274      * modifier {@link Modifier#STRICT strictfp}, with a mask value of
275      * <code>{@value "0x%04x" Modifier#STRICT}</code>.
276      *
277      * @apiNote
278      * The {@code ACC_STRICT} access flag is defined for class file
279      * major versions 46 through 60, inclusive (JVMS {@jvms 4.6}),
280      * corresponding to Java SE 1.2 through 16.
281      */
282     STRICT(Modifier.STRICT, true, Location.EMPTY_SET,
283            List.of(Map.entry(RELEASE_16, Location.SET_METHOD),
284                    Map.entry(RELEASE_1, Location.EMPTY_SET))),
285 
286     /**
287      * The access flag {@code ACC_STRICT_INIT}, with a mask value of
288      * <code>{@value "0x%04x" java.lang.classfile.ClassFile#ACC_STRICT_INIT}</code>.
289      *
290      * @jvms 4.5 Fields
291      * @since Valhalla
292      */
293     @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
294     STRICT_INIT(ACC_STRICT_INIT, false,
295                 Location.SET_FIELD,
296                 List.of(Map.entry(latest(), Location.EMPTY_SET))),
297 
298     /**
299      * The access flag {@code ACC_SYNTHETIC} with a mask value of
300      * <code>{@value "0x%04x" Modifier#SYNTHETIC}</code>.
301      * @see Class#isSynthetic()
302      * @see Executable#isSynthetic()
303      * @see java.lang.module.ModuleDescriptor.Modifier#SYNTHETIC
304      */
305     SYNTHETIC(Modifier.SYNTHETIC, false, Location.SET_SYNTHETIC_9,
306               List.of(Map.entry(RELEASE_8, Location.SET_SYNTHETIC_8),
307                       Map.entry(RELEASE_7, Location.SET_SYNTHETIC_5),
308                       Map.entry(RELEASE_4, Location.EMPTY_SET))),
309 
310     /**
311      * The access flag {@code ACC_ANNOTATION} with a mask value of
312      * <code>{@value "0x%04x" Modifier#ANNOTATION}</code>.
313      * @see Class#isAnnotation()
314      */
315     ANNOTATION(Modifier.ANNOTATION, false, Location.SET_CLASS_INNER_CLASS,
316                List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
317 

367     public int mask() {
368         return mask;
369     }
370 
371     /**
372      * {@return whether or not this flag has a directly corresponding
373      * modifier in the Java programming language}
374      */
375     public boolean sourceModifier() {
376         return sourceModifier;
377     }
378 
379     /**
380      * {@return locations this flag can be applied to in the current class file
381      * format version}
382      * <p>
383      * This method returns an empty set if this flag is not defined in
384      * the current class file format version.
385      */
386     public Set<Location> locations() {
387         return locations(latest());
388     }
389 
390     /**
391      * {@return locations this flag can be applied to in the given class file
392      * format version}
393      * <p>
394      * This method returns an empty set if this flag is not defined in
395      * the given {@code cffv}.
396      *
397      * @param cffv the class file format version to use
398      * @throws NullPointerException if the parameter is {@code null}
399      */
400     public Set<Location> locations(ClassFileFormatVersion cffv) {
401         return Location.findInHistory(locations, historicalLocations, cffv);
402     }
403 
404     /**
405      * {@return an unmodifiable set of access flags for the given mask value
406      * appropriate for the location in the current class file format version}
407      *
408      * @param mask bit mask of access flags
409      * @param location context to interpret mask value
410      * @throws IllegalArgumentException if the mask contains bit
411      * positions not defined for the location in the current class file format
412      * @throws NullPointerException if {@code location} is {@code null}
413      */
414     public static Set<AccessFlag> maskToAccessFlags(int mask, Location location) {
415         return maskToAccessFlags(mask, location, latest());







416     }
417 
418     /**
419      * {@return an unmodifiable set of access flags for the given mask value
420      * appropriate for the location in the given class file format version}
421      *
422      * @param mask bit mask of access flags
423      * @param location context to interpret mask value
424      * @param cffv the class file format to interpret mask value
425      * @throws IllegalArgumentException if the mask contains bit
426      * positions not defined for the location in the given class file format
427      * @throws NullPointerException if {@code location} or {@code cffv} is {@code null}
428      * @since 25
429      */
430     public static Set<AccessFlag> maskToAccessFlags(int mask, Location location, ClassFileFormatVersion cffv) {
431         var definition = findDefinition(location, cffv);  // null checks location
432         int unmatchedMask = mask & (~location.flagsMask(cffv));  // null checks cffv
433         if (unmatchedMask != 0) {
434             throw new IllegalArgumentException("Unmatched bit position 0x" +
435                     Integer.toHexString(unmatchedMask) +
436                     " for location " + location +
437                     " for class file format " + cffv);
438         }
439         return new AccessFlagSet(definition, mask);
440     }
441 
442     /**
443      * A location within a {@code class} file where flags can be applied.
444      * <p>
445      * Note that since these locations represent {@code class} file structures
446      * rather than language structures, many language structures, such
447      * as constructors and interfaces, are <em>not</em> present.
448      * @since 20
449      */
450     public enum Location {
451         /**
452          * Class location.
453          *
454          * @see Class#accessFlags()
455          * @see ClassModel#flags()
456          * @see Modifier#classModifiers()
457          * @see Modifier#interfaceModifiers()
458          * @jvms 4.1 The {@code ClassFile} Structure
459          */
460         CLASS(ACC_PUBLIC | ACC_FINAL | ACC_IDENTITY |
461               ACC_INTERFACE | ACC_ABSTRACT |
462               ACC_SYNTHETIC | ACC_ANNOTATION |
463               ACC_ENUM | ACC_MODULE,
464               List.of(Map.entry(RELEASE_8, // no module
465                                 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
466                                 ACC_INTERFACE | ACC_ABSTRACT |
467                                 ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM),
468                       Map.entry(RELEASE_4, // no synthetic, annotation, enum
469                                 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
470                                 ACC_INTERFACE | ACC_ABSTRACT))),
471 
472         /**
473          * Field location.
474          *
475          * @see Field#accessFlags()
476          * @see FieldModel#flags()
477          * @see Modifier#fieldModifiers()
478          * @jvms 4.5 Fields
479          */
480         FIELD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
481               ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
482               ACC_TRANSIENT | ACC_SYNTHETIC | ACC_ENUM | ACC_STRICT_INIT,
483               List.of(Map.entry(latest(), // no strict_init
484                                 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
485                                 ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
486                                 ACC_TRANSIENT | ACC_SYNTHETIC | ACC_ENUM),
487                       Map.entry(RELEASE_4, // no synthetic, enum
488                                 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
489                                 ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
490                                 ACC_TRANSIENT))),
491 
492         /**
493          * Method location.
494          *
495          * @see Executable#accessFlags()
496          * @see MethodModel#flags()
497          * @see Modifier#methodModifiers()
498          * @see Modifier#constructorModifiers()
499          * @jvms 4.6 Methods
500          */
501         METHOD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
502                ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
503                ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
504                ACC_ABSTRACT | ACC_SYNTHETIC,
505                List.of(Map.entry(RELEASE_16, // had strict
506                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
507                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
508                                  ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
509                                  ACC_ABSTRACT | ACC_STRICT | ACC_SYNTHETIC),
510                        Map.entry(RELEASE_4, // no bridge, varargs, synthetic
511                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
512                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
513                                  ACC_NATIVE | ACC_ABSTRACT | ACC_STRICT),
514                        Map.entry(RELEASE_1, // no strict
515                                  ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
516                                  ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
517                                  ACC_NATIVE | ACC_ABSTRACT))),
518 
519         /**
520          * Inner class location.
521          *
522          * @see Class#accessFlags()
523          * @see InnerClassInfo#flags()
524          * @see Modifier#classModifiers()
525          * @see Modifier#interfaceModifiers()
526          * @jvms 4.7.6 The {@code InnerClasses} Attribute
527          */
528         INNER_CLASS(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED | ACC_IDENTITY |
529                     ACC_STATIC | ACC_FINAL | ACC_INTERFACE | ACC_ABSTRACT |
530                     ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM,
531                     List.of(Map.entry(latest(), // no identity
532                                       ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
533                                       ACC_STATIC | ACC_FINAL | ACC_INTERFACE | ACC_ABSTRACT |
534                                       ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM),
535                             Map.entry(RELEASE_4, // no synthetic, annotation, enum
536                                       ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
537                                       ACC_STATIC | ACC_FINAL | ACC_INTERFACE |
538                                       ACC_ABSTRACT),
539                             Map.entry(RELEASE_0, 0))), // did not exist
540 
541         /**
542          * Method parameter location.
543          *
544          * @see Parameter#accessFlags()
545          * @see MethodParameterInfo#flags()
546          * @see Modifier#parameterModifiers()
547          * @jvms 4.7.24 The {@code MethodParameters} Attribute
548          */
549         METHOD_PARAMETER(ACC_FINAL | ACC_SYNTHETIC | ACC_MANDATED,
550                          List.of(Map.entry(RELEASE_7, 0))),  // did not exist
551 
552         /**
553          * Module location.
554          *
555          * @see ModuleDescriptor#accessFlags()
556          * @see ModuleAttribute#moduleFlags()
557          * @jvms 4.7.25 The {@code Module} Attribute
558          */

635                      MODULE_EXPORTS, MODULE_OPENS);
636         private static final Set<Location> SET_MANDATED_9 =
637             Set.of(METHOD_PARAMETER, // From 8
638                    // Starting in 9
639                    MODULE, MODULE_REQUIRES,
640                    MODULE_EXPORTS, MODULE_OPENS);
641 
642         private final int flagsMask;
643         private final List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks;
644 
645         Location(int flagsMask,
646                  List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks) {
647             this.flagsMask = flagsMask;
648             this.historicalFlagsMasks = ensureHistoryOrdered(historicalFlagsMasks);
649         }
650 
651         // Ensures the historical versions are from newest to oldest and do not include the latest
652         // These 2 utilities reside in Location because Location must be initialized before AccessFlag
653         private static <T> List<Map.Entry<ClassFileFormatVersion, T>> ensureHistoryOrdered(
654                 List<Map.Entry<ClassFileFormatVersion, T>> history) {
655             ClassFileFormatVersion lastVersion = CURRENT_PREVIEW_FEATURES;
656             for (var e : history) {
657                 var historyVersion = e.getKey();
658                 if (lastVersion.compareTo(historyVersion) <= 0) {
659                     throw new IllegalArgumentException("Versions out of order");
660                 }
661                 lastVersion = historyVersion;
662             }
663             return history;
664         }
665 
666         private static <T> T findInHistory(T candidate, List<Map.Entry<ClassFileFormatVersion, T>> history,
667                                            ClassFileFormatVersion cffv) {
668             Objects.requireNonNull(cffv);
669             for (var e : history) {
670                 if (e.getKey().compareTo(cffv) < 0) {
671                     // last version found was valid
672                     return candidate;
673                 }
674                 candidate = e.getValue();
675             }
676             return candidate;
677         }
678 
679         /**
680          * {@return the union of masks of all access flags defined for
681          * this location in the current class file format version}
682          * <p>
683          * This method returns {@code 0} if this location does not exist in
684          * the current class file format version.
685          *
686          * @since 25
687          */
688         public int flagsMask() {
689             return flagsMask(latest());
690         }
691 
692         /**
693          * {@return the union of masks of all access flags defined for
694          * this location in the given class file format version}
695          * <p>
696          * This method returns {@code 0} if this location does not exist in
697          * the given {@code cffv}.
698          *
699          * @param cffv the class file format version
700          * @throws NullPointerException if {@code cffv} is {@code null}
701          * @since 25
702          */
703         public int flagsMask(ClassFileFormatVersion cffv) {
704             return findInHistory(flagsMask, historicalFlagsMasks, cffv);
705         }
706 
707         /**
708          * {@return the set of access flags defined for this location in the
709          * current class file format version}  The set is immutable.
710          * <p>
711          * This method returns an empty set if this location does not exist
712          * in the current class file format version.
713          *
714          * @since 25
715          */
716         public Set<AccessFlag> flags() {
717             return flags(latest());
718         }
719 
720         /**
721          * {@return the set of access flags defined for this location in the
722          * given class file format version}  The set is immutable.
723          * <p>
724          * This method returns an empty set if this location does not exist
725          * in the given {@code cffv}.
726          *
727          * @param cffv the class file format version
728          * @throws NullPointerException if {@code cffv} is {@code null}
729          * @since 25
730          */
731         public Set<AccessFlag> flags(ClassFileFormatVersion cffv) {
732             // implicit null check cffv
733             return new AccessFlagSet(findDefinition(this, cffv), flagsMask(cffv));
734         }
735     }
736 
737     private static AccessFlag[] createDefinition(AccessFlag... known) {
738         var ret = new AccessFlag[Character.SIZE];
739         for (var flag : known) {
740             var mask = flag.mask;
741             int pos = Integer.numberOfTrailingZeros(mask);
742             assert ret[pos] == null : ret[pos] + " " + flag;
743             ret[pos] = flag;
744         }
745         return ret;
746     }
747 
748     private static AccessFlag[] findDefinition(Location location, ClassFileFormatVersion cffv) {

749         return switch (location) {
750             case CLASS -> cffv == CURRENT_PREVIEW_FEATURES ? CLASS_PREVIEW_FLAGS : CLASS_FLAGS;
751             case FIELD -> cffv == CURRENT_PREVIEW_FEATURES ? FIELD_PREVIEW_FLAGS : FIELD_FLAGS;
752             case METHOD -> METHOD_FLAGS;
753             case INNER_CLASS -> cffv == CURRENT_PREVIEW_FEATURES ? INNER_CLASS_PREVIEW_FLAGS : INNER_CLASS_FLAGS;
754             case METHOD_PARAMETER -> METHOD_PARAMETER_FLAGS;
755             case MODULE -> MODULE_FLAGS;
756             case MODULE_REQUIRES -> MODULE_REQUIRES_FLAGS;
757             case MODULE_EXPORTS -> MODULE_EXPORTS_FLAGS;
758             case MODULE_OPENS -> MODULE_OPENS_FLAGS;
759         };
760     }
761 
762     private static final @Stable AccessFlag[] // Can use stable array and lazy init in the future
763             CLASS_FLAGS         = createDefinition(PUBLIC, FINAL, SUPER, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM, MODULE),
764             CLASS_PREVIEW_FLAGS = createDefinition(PUBLIC, FINAL, IDENTITY, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM, MODULE), // identity
765             FIELD_FLAGS         = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, VOLATILE, TRANSIENT, SYNTHETIC, ENUM),
766             FIELD_PREVIEW_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, VOLATILE, TRANSIENT, SYNTHETIC, ENUM, STRICT_INIT), // strict
767             METHOD_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, SYNCHRONIZED, BRIDGE, VARARGS, NATIVE, ABSTRACT, STRICT, SYNTHETIC),
768             INNER_CLASS_FLAGS         = createDefinition(PUBLIC, PRIVATE, PROTECTED, STATIC, FINAL, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM),
769             INNER_CLASS_PREVIEW_FLAGS = createDefinition(PUBLIC, PRIVATE, PROTECTED, IDENTITY, STATIC, FINAL, INTERFACE, ABSTRACT, SYNTHETIC, ANNOTATION, ENUM),  // identity
770             METHOD_PARAMETER_FLAGS = createDefinition(FINAL, SYNTHETIC, MANDATED),
771             MODULE_FLAGS = createDefinition(OPEN, SYNTHETIC, MANDATED),
772             MODULE_REQUIRES_FLAGS = createDefinition(TRANSITIVE, STATIC_PHASE, SYNTHETIC, MANDATED),
773             MODULE_EXPORTS_FLAGS = createDefinition(SYNTHETIC, MANDATED),
774             MODULE_OPENS_FLAGS = createDefinition(SYNTHETIC, MANDATED);
775 
776     private static int undefinedMask(AccessFlag[] definition, int mask) {
777         assert definition.length == Character.SIZE;
778         int definedMask = 0;
779         for (int i = 0; i < Character.SIZE; i++) {
780             if (definition[i] != null) {
781                 definedMask |= 1 << i;
782             }
783         }
784         return mask & ~definedMask;
785     }
786 
787     private static final class AccessFlagSet extends AbstractSet<AccessFlag> {
788         private final @Stable AccessFlag[] definition;
789         private final int mask;
< prev index next >