1 /*
2 * Copyright (c) 1996, 2023, 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.access.SharedSecrets;
29 import jdk.internal.reflect.CallerSensitive;
30 import jdk.internal.reflect.FieldAccessor;
31 import jdk.internal.reflect.Reflection;
32 import jdk.internal.vm.annotation.ForceInline;
33 import jdk.internal.vm.annotation.Stable;
34 import sun.reflect.generics.repository.FieldRepository;
35 import sun.reflect.generics.factory.CoreReflectionFactory;
36 import sun.reflect.generics.factory.GenericsFactory;
37 import sun.reflect.generics.scope.ClassScope;
38 import java.lang.annotation.Annotation;
39 import java.util.Map;
40 import java.util.Set;
41 import java.util.Objects;
42 import sun.reflect.annotation.AnnotationParser;
43 import sun.reflect.annotation.AnnotationSupport;
44 import sun.reflect.annotation.TypeAnnotation;
45 import sun.reflect.annotation.TypeAnnotationParser;
46
47 /**
48 * A {@code Field} provides information about, and dynamic access to, a
49 * single field of a class or an interface. The reflected field may
50 * be a class (static) field or an instance field.
51 *
52 * <p>A {@code Field} permits widening conversions to occur during a get or
53 * set access operation, but throws an {@code IllegalArgumentException} if a
54 * narrowing conversion would occur.
55 *
56 * @see Member
57 * @see java.lang.Class
58 * @see java.lang.Class#getFields()
59 * @see java.lang.Class#getField(String)
60 * @see java.lang.Class#getDeclaredFields()
61 * @see java.lang.Class#getDeclaredField(String)
62 *
63 * @author Kenneth Russell
64 * @author Nakul Saraiya
65 * @since 1.1
66 */
67 public final
68 class Field extends AccessibleObject implements Member {
69 private final Class<?> clazz;
70 private final int slot;
71 // This is guaranteed to be interned by the VM in the 1.4
72 // reflection implementation
73 private final String name;
74 private final Class<?> type;
75 private final int modifiers;
76 private final boolean trustedFinal;
77 // Generics and annotations support
78 private final transient String signature;
79 // generic info repository; lazily initialized
80 private transient volatile FieldRepository genericInfo;
81 private final byte[] annotations;
82 // Cached field accessor created without override
83 @Stable
84 private FieldAccessor fieldAccessor;
85 // Cached field accessor created with override
86 @Stable
87 private FieldAccessor overrideFieldAccessor;
88 // For sharing of FieldAccessors. This branching structure is
89 // currently only two levels deep (i.e., one root Field and
90 // potentially many Field objects pointing to it.)
91 //
92 // If this branching structure would ever contain cycles, deadlocks can
93 // occur in annotation code.
94 private Field root;
95
96 // Generics infrastructure
97
98 private String getGenericSignature() {return signature;}
99
100 // Accessor for factory
101 private GenericsFactory getFactory() {
102 Class<?> c = getDeclaringClass();
103 // create scope and factory
104 return CoreReflectionFactory.make(c, ClassScope.make(c));
105 }
106
107 // Accessor for generic info repository
108 private FieldRepository getGenericInfo() {
109 var genericInfo = this.genericInfo;
110 // lazily initialize repository if necessary
111 if (genericInfo == null) {
112 // create and cache generic info repository
113 genericInfo = FieldRepository.make(getGenericSignature(),
114 getFactory());
115 this.genericInfo = genericInfo;
116 }
117 return genericInfo; //return cached repository
118 }
119
120
121 /**
122 * Package-private constructor
123 */
124 @SuppressWarnings("deprecation")
125 Field(Class<?> declaringClass,
126 String name,
127 Class<?> type,
128 int modifiers,
129 boolean trustedFinal,
130 int slot,
131 String signature,
132 byte[] annotations)
133 {
134 this.clazz = declaringClass;
135 this.name = name;
136 this.type = type;
137 this.modifiers = modifiers;
138 this.trustedFinal = trustedFinal;
139 this.slot = slot;
140 this.signature = signature;
141 this.annotations = annotations;
142 }
143
144 /**
145 * Package-private routine (exposed to java.lang.Class via
146 * ReflectAccess) which returns a copy of this Field. The copy's
147 * "root" field points to this Field.
148 */
149 Field copy() {
150 // This routine enables sharing of FieldAccessor objects
151 // among Field objects which refer to the same underlying
152 // method in the VM. (All of this contortion is only necessary
153 // because of the "accessibility" bit in AccessibleObject,
154 // which implicitly requires that new java.lang.reflect
155 // objects be fabricated for each reflective call on Class
156 // objects.)
157 if (this.root != null)
158 throw new IllegalArgumentException("Can not copy a non-root Field");
159
160 Field res = new Field(clazz, name, type, modifiers, trustedFinal, slot, signature, annotations);
161 res.root = this;
162 // Might as well eagerly propagate this if already present
163 res.fieldAccessor = fieldAccessor;
164 res.overrideFieldAccessor = overrideFieldAccessor;
165
166 return res;
167 }
168
169 /**
170 * @throws InaccessibleObjectException {@inheritDoc}
171 * @throws SecurityException {@inheritDoc}
172 */
173 @Override
174 @CallerSensitive
175 public void setAccessible(boolean flag) {
176 AccessibleObject.checkPermission();
177 if (flag) checkCanSetAccessible(Reflection.getCallerClass());
178 setAccessible0(flag);
179 }
180
181 @Override
182 void checkCanSetAccessible(Class<?> caller) {
183 checkCanSetAccessible(caller, clazz);
184 }
185
186 /**
187 * Returns the {@code Class} object representing the class or interface
188 * that declares the field represented by this {@code Field} object.
189 */
190 @Override
191 public Class<?> getDeclaringClass() {
192 return clazz;
193 }
194
195 /**
196 * Returns the name of the field represented by this {@code Field} object.
197 */
198 public String getName() {
199 return name;
200 }
201
202 /**
203 * Returns the Java language modifiers for the field represented
204 * by this {@code Field} object, as an integer. The {@code Modifier} class should
205 * be used to decode the modifiers.
206 *
207 * @see Modifier
208 * @see #accessFlags()
209 * @jls 8.3 Field Declarations
210 * @jls 9.3 Field (Constant) Declarations
211 */
212 public int getModifiers() {
213 return modifiers;
214 }
215
216 /**
217 * {@return an unmodifiable set of the {@linkplain AccessFlag
218 * access flags} for this field, possibly empty}
219 * @see #getModifiers()
220 * @jvms 4.5 Fields
221 * @since 20
222 */
223 @Override
224 public Set<AccessFlag> accessFlags() {
225 return AccessFlag.maskToAccessFlags(getModifiers(), AccessFlag.Location.FIELD);
226 }
227
228 /**
229 * Returns {@code true} if this field represents an element of
230 * an enumerated class; returns {@code false} otherwise.
231 *
232 * @return {@code true} if and only if this field represents an element of
233 * an enumerated class.
234 * @since 1.5
235 * @jls 8.9.1 Enum Constants
236 */
237 public boolean isEnumConstant() {
238 return (getModifiers() & Modifier.ENUM) != 0;
239 }
240
241 /**
242 * Returns {@code true} if this field is a synthetic
243 * field; returns {@code false} otherwise.
244 *
245 * @return true if and only if this field is a synthetic
246 * field as defined by the Java Language Specification.
247 * @since 1.5
248 * @see <a
249 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
250 * programming language and JVM modeling in core reflection</a>
251 */
252 public boolean isSynthetic() {
253 return Modifier.isSynthetic(getModifiers());
254 }
255
256 /**
257 * Returns a {@code Class} object that identifies the
258 * declared type for the field represented by this
259 * {@code Field} object.
260 *
261 * @return a {@code Class} object identifying the declared
262 * type of the field represented by this object
263 */
264 public Class<?> getType() {
265 return type;
266 }
267
268 /**
269 * Returns a {@code Type} object that represents the declared type for
270 * the field represented by this {@code Field} object.
271 *
272 * <p>If the declared type of the field is a parameterized type,
273 * the {@code Type} object returned must accurately reflect the
274 * actual type arguments used in the source code.
275 *
276 * <p>If the type of the underlying field is a type variable or a
277 * parameterized type, it is created. Otherwise, it is resolved.
278 *
279 * @return a {@code Type} object that represents the declared type for
280 * the field represented by this {@code Field} object
281 * @throws GenericSignatureFormatError if the generic field
282 * signature does not conform to the format specified in
283 * <cite>The Java Virtual Machine Specification</cite>
284 * @throws TypeNotPresentException if the generic type
285 * signature of the underlying field refers to a non-existent
286 * class or interface declaration
287 * @throws MalformedParameterizedTypeException if the generic
288 * signature of the underlying field refers to a parameterized type
289 * that cannot be instantiated for any reason
290 * @since 1.5
291 */
292 public Type getGenericType() {
293 if (getGenericSignature() != null)
294 return getGenericInfo().getGenericType();
295 else
296 return getType();
297 }
298
299
300 /**
301 * Compares this {@code Field} against the specified object. Returns
302 * true if the objects are the same. Two {@code Field} objects are the same if
303 * they were declared by the same class and have the same name
304 * and type.
305 */
306 public boolean equals(Object obj) {
307 if (obj instanceof Field other) {
308 return (getDeclaringClass() == other.getDeclaringClass())
309 && (getName() == other.getName())
310 && (getType() == other.getType());
311 }
312 return false;
313 }
314
315 /**
316 * Returns a hashcode for this {@code Field}. This is computed as the
317 * exclusive-or of the hashcodes for the underlying field's
318 * declaring class name and its name.
319 */
320 public int hashCode() {
321 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
322 }
323
324 /**
325 * Returns a string describing this {@code Field}. The format is
326 * the access modifiers for the field, if any, followed
327 * by the field type, followed by a space, followed by
328 * the fully-qualified name of the class declaring the field,
329 * followed by a period, followed by the name of the field.
330 * For example:
331 * <pre>
332 * public static final int java.lang.Thread.MIN_PRIORITY
333 * private int java.io.FileDescriptor.fd
334 * </pre>
335 *
336 * <p>The modifiers are placed in canonical order as specified by
337 * "The Java Language Specification". This is {@code public},
338 * {@code protected} or {@code private} first, and then other
339 * modifiers in the following order: {@code static}, {@code final},
340 * {@code transient}, {@code volatile}.
341 *
342 * @return a string describing this {@code Field}
343 * @jls 8.3.1 Field Modifiers
344 */
345 public String toString() {
346 int mod = getModifiers();
347 return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
348 + getType().getTypeName() + " "
349 + getDeclaringClass().getTypeName() + "."
350 + getName());
351 }
352
353 @Override
354 String toShortString() {
355 return "field " + getDeclaringClass().getTypeName() + "." + getName();
356 }
357
358 /**
359 * Returns a string describing this {@code Field}, including
360 * its generic type. The format is the access modifiers for the
361 * field, if any, followed by the generic field type, followed by
362 * a space, followed by the fully-qualified name of the class
363 * declaring the field, followed by a period, followed by the name
364 * of the field.
365 *
366 * <p>The modifiers are placed in canonical order as specified by
367 * "The Java Language Specification". This is {@code public},
368 * {@code protected} or {@code private} first, and then other
369 * modifiers in the following order: {@code static}, {@code final},
370 * {@code transient}, {@code volatile}.
371 *
372 * @return a string describing this {@code Field}, including
373 * its generic type
374 *
375 * @since 1.5
376 * @jls 8.3.1 Field Modifiers
377 */
378 public String toGenericString() {
379 int mod = getModifiers();
380 Type fieldType = getGenericType();
381 return (((mod == 0) ? "" : (Modifier.toString(mod) + " "))
382 + fieldType.getTypeName() + " "
383 + getDeclaringClass().getTypeName() + "."
384 + getName());
385 }
386
387 /**
388 * Returns the value of the field represented by this {@code Field}, on
389 * the specified object. The value is automatically wrapped in an
390 * object if it has a primitive type.
391 *
392 * <p>The underlying field's value is obtained as follows:
393 *
394 * <p>If the underlying field is a static field, the {@code obj} argument
395 * is ignored; it may be null.
396 *
397 * <p>Otherwise, the underlying field is an instance field. If the
398 * specified {@code obj} argument is null, the method throws a
399 * {@code NullPointerException}. If the specified object is not an
400 * instance of the class or interface declaring the underlying
401 * field, the method throws an {@code IllegalArgumentException}.
402 *
403 * <p>If this {@code Field} object is enforcing Java language access control, and
404 * the underlying field is inaccessible, the method throws an
405 * {@code IllegalAccessException}.
406 * If the underlying field is static, the class that declared the
407 * field is initialized if it has not already been initialized.
408 *
409 * <p>Otherwise, the value is retrieved from the underlying instance
410 * or static field. If the field has a primitive type, the value
411 * is wrapped in an object before being returned, otherwise it is
412 * returned as is.
413 *
414 * <p>If the field is hidden in the type of {@code obj},
415 * the field's value is obtained according to the preceding rules.
416 *
417 * @param obj object from which the represented field's value is
418 * to be extracted
419 * @return the value of the represented field in object
420 * {@code obj}; primitive values are wrapped in an appropriate
421 * object before being returned
422 *
423 * @throws IllegalAccessException if this {@code Field} object
424 * is enforcing Java language access control and the underlying
425 * field is inaccessible.
426 * @throws IllegalArgumentException if the specified object is not an
427 * instance of the class or interface declaring the underlying
428 * field (or a subclass or implementor thereof).
429 * @throws NullPointerException if the specified object is null
430 * and the field is an instance field.
431 * @throws ExceptionInInitializerError if the initialization provoked
432 * by this method fails.
433 */
434 @CallerSensitive
435 @ForceInline // to ensure Reflection.getCallerClass optimization
436 public Object get(Object obj)
437 throws IllegalArgumentException, IllegalAccessException
438 {
439 if (!override) {
440 Class<?> caller = Reflection.getCallerClass();
441 checkAccess(caller, obj);
442 return getFieldAccessor().get(obj);
443 } else {
444 return getOverrideFieldAccessor().get(obj);
445 }
446 }
447
448 /**
449 * Gets the value of a static or instance {@code boolean} field.
450 *
451 * @param obj the object to extract the {@code boolean} value
452 * from
453 * @return the value of the {@code boolean} field
454 *
455 * @throws IllegalAccessException if this {@code Field} object
456 * is enforcing Java language access control and the underlying
457 * field is inaccessible.
458 * @throws IllegalArgumentException if the specified object is not
459 * an instance of the class or interface declaring the
460 * underlying field (or a subclass or implementor
461 * thereof), or if the field value cannot be
462 * converted to the type {@code boolean} by a
463 * widening conversion.
464 * @throws NullPointerException if the specified object is null
465 * and the field is an instance field.
466 * @throws ExceptionInInitializerError if the initialization provoked
467 * by this method fails.
468 * @see Field#get
469 */
470 @CallerSensitive
471 @ForceInline // to ensure Reflection.getCallerClass optimization
472 public boolean getBoolean(Object obj)
473 throws IllegalArgumentException, IllegalAccessException
474 {
475 if (!override) {
476 Class<?> caller = Reflection.getCallerClass();
477 checkAccess(caller, obj);
478 return getFieldAccessor().getBoolean(obj);
479 } else {
480 return getOverrideFieldAccessor().getBoolean(obj);
481 }
482 }
483
484 /**
485 * Gets the value of a static or instance {@code byte} field.
486 *
487 * @param obj the object to extract the {@code byte} value
488 * from
489 * @return the value of the {@code byte} field
490 *
491 * @throws IllegalAccessException if this {@code Field} object
492 * is enforcing Java language access control and the underlying
493 * field is inaccessible.
494 * @throws IllegalArgumentException if the specified object is not
495 * an instance of the class or interface declaring the
496 * underlying field (or a subclass or implementor
497 * thereof), or if the field value cannot be
498 * converted to the type {@code byte} by a
499 * widening conversion.
500 * @throws NullPointerException if the specified object is null
501 * and the field is an instance field.
502 * @throws ExceptionInInitializerError if the initialization provoked
503 * by this method fails.
504 * @see Field#get
505 */
506 @CallerSensitive
507 @ForceInline // to ensure Reflection.getCallerClass optimization
508 public byte getByte(Object obj)
509 throws IllegalArgumentException, IllegalAccessException
510 {
511 if (!override) {
512 Class<?> caller = Reflection.getCallerClass();
513 checkAccess(caller, obj);
514 return getFieldAccessor().getByte(obj);
515 } else {
516 return getOverrideFieldAccessor().getByte(obj);
517 }
518 }
519
520 /**
521 * Gets the value of a static or instance field of type
522 * {@code char} or of another primitive type convertible to
523 * type {@code char} via a widening conversion.
524 *
525 * @param obj the object to extract the {@code char} value
526 * from
527 * @return the value of the field converted to type {@code char}
528 *
529 * @throws IllegalAccessException if this {@code Field} object
530 * is enforcing Java language access control and the underlying
531 * field is inaccessible.
532 * @throws IllegalArgumentException if the specified object is not
533 * an instance of the class or interface declaring the
534 * underlying field (or a subclass or implementor
535 * thereof), or if the field value cannot be
536 * converted to the type {@code char} by a
537 * widening conversion.
538 * @throws NullPointerException if the specified object is null
539 * and the field is an instance field.
540 * @throws ExceptionInInitializerError if the initialization provoked
541 * by this method fails.
542 * @see Field#get
543 */
544 @CallerSensitive
545 @ForceInline // to ensure Reflection.getCallerClass optimization
546 public char getChar(Object obj)
547 throws IllegalArgumentException, IllegalAccessException
548 {
549 if (!override) {
550 Class<?> caller = Reflection.getCallerClass();
551 checkAccess(caller, obj);
552 return getFieldAccessor().getChar(obj);
553 } else {
554 return getOverrideFieldAccessor().getChar(obj);
555 }
556 }
557
558 /**
559 * Gets the value of a static or instance field of type
560 * {@code short} or of another primitive type convertible to
561 * type {@code short} via a widening conversion.
562 *
563 * @param obj the object to extract the {@code short} value
564 * from
565 * @return the value of the field converted to type {@code short}
566 *
567 * @throws IllegalAccessException if this {@code Field} object
568 * is enforcing Java language access control and the underlying
569 * field is inaccessible.
570 * @throws IllegalArgumentException if the specified object is not
571 * an instance of the class or interface declaring the
572 * underlying field (or a subclass or implementor
573 * thereof), or if the field value cannot be
574 * converted to the type {@code short} by a
575 * widening conversion.
576 * @throws NullPointerException if the specified object is null
577 * and the field is an instance field.
578 * @throws ExceptionInInitializerError if the initialization provoked
579 * by this method fails.
580 * @see Field#get
581 */
582 @CallerSensitive
583 @ForceInline // to ensure Reflection.getCallerClass optimization
584 public short getShort(Object obj)
585 throws IllegalArgumentException, IllegalAccessException
586 {
587 if (!override) {
588 Class<?> caller = Reflection.getCallerClass();
589 checkAccess(caller, obj);
590 return getFieldAccessor().getShort(obj);
591 } else {
592 return getOverrideFieldAccessor().getShort(obj);
593 }
594 }
595
596 /**
597 * Gets the value of a static or instance field of type
598 * {@code int} or of another primitive type convertible to
599 * type {@code int} via a widening conversion.
600 *
601 * @param obj the object to extract the {@code int} value
602 * from
603 * @return the value of the field converted to type {@code int}
604 *
605 * @throws IllegalAccessException if this {@code Field} object
606 * is enforcing Java language access control and the underlying
607 * field is inaccessible.
608 * @throws IllegalArgumentException if the specified object is not
609 * an instance of the class or interface declaring the
610 * underlying field (or a subclass or implementor
611 * thereof), or if the field value cannot be
612 * converted to the type {@code int} by a
613 * widening conversion.
614 * @throws NullPointerException if the specified object is null
615 * and the field is an instance field.
616 * @throws ExceptionInInitializerError if the initialization provoked
617 * by this method fails.
618 * @see Field#get
619 */
620 @CallerSensitive
621 @ForceInline // to ensure Reflection.getCallerClass optimization
622 public int getInt(Object obj)
623 throws IllegalArgumentException, IllegalAccessException
624 {
625 if (!override) {
626 Class<?> caller = Reflection.getCallerClass();
627 checkAccess(caller, obj);
628 return getFieldAccessor().getInt(obj);
629 } else {
630 return getOverrideFieldAccessor().getInt(obj);
631 }
632 }
633
634 /**
635 * Gets the value of a static or instance field of type
636 * {@code long} or of another primitive type convertible to
637 * type {@code long} via a widening conversion.
638 *
639 * @param obj the object to extract the {@code long} value
640 * from
641 * @return the value of the field converted to type {@code long}
642 *
643 * @throws IllegalAccessException if this {@code Field} object
644 * is enforcing Java language access control and the underlying
645 * field is inaccessible.
646 * @throws IllegalArgumentException if the specified object is not
647 * an instance of the class or interface declaring the
648 * underlying field (or a subclass or implementor
649 * thereof), or if the field value cannot be
650 * converted to the type {@code long} by a
651 * widening conversion.
652 * @throws NullPointerException if the specified object is null
653 * and the field is an instance field.
654 * @throws ExceptionInInitializerError if the initialization provoked
655 * by this method fails.
656 * @see Field#get
657 */
658 @CallerSensitive
659 @ForceInline // to ensure Reflection.getCallerClass optimization
660 public long getLong(Object obj)
661 throws IllegalArgumentException, IllegalAccessException
662 {
663 if (!override) {
664 Class<?> caller = Reflection.getCallerClass();
665 checkAccess(caller, obj);
666 return getFieldAccessor().getLong(obj);
667 } else {
668 return getOverrideFieldAccessor().getLong(obj);
669 }
670 }
671
672 /**
673 * Gets the value of a static or instance field of type
674 * {@code float} or of another primitive type convertible to
675 * type {@code float} via a widening conversion.
676 *
677 * @param obj the object to extract the {@code float} value
678 * from
679 * @return the value of the field converted to type {@code float}
680 *
681 * @throws IllegalAccessException if this {@code Field} object
682 * is enforcing Java language access control and the underlying
683 * field is inaccessible.
684 * @throws IllegalArgumentException if the specified object is not
685 * an instance of the class or interface declaring the
686 * underlying field (or a subclass or implementor
687 * thereof), or if the field value cannot be
688 * converted to the type {@code float} by a
689 * widening conversion.
690 * @throws NullPointerException if the specified object is null
691 * and the field is an instance field.
692 * @throws ExceptionInInitializerError if the initialization provoked
693 * by this method fails.
694 * @see Field#get
695 */
696 @CallerSensitive
697 @ForceInline // to ensure Reflection.getCallerClass optimization
698 public float getFloat(Object obj)
699 throws IllegalArgumentException, IllegalAccessException
700 {
701 if (!override) {
702 Class<?> caller = Reflection.getCallerClass();
703 checkAccess(caller, obj);
704 return getFieldAccessor().getFloat(obj);
705 } else {
706 return getOverrideFieldAccessor().getFloat(obj);
707 }
708 }
709
710 /**
711 * Gets the value of a static or instance field of type
712 * {@code double} or of another primitive type convertible to
713 * type {@code double} via a widening conversion.
714 *
715 * @param obj the object to extract the {@code double} value
716 * from
717 * @return the value of the field converted to type {@code double}
718 *
719 * @throws IllegalAccessException if this {@code Field} object
720 * is enforcing Java language access control and the underlying
721 * field is inaccessible.
722 * @throws IllegalArgumentException if the specified object is not
723 * an instance of the class or interface declaring the
724 * underlying field (or a subclass or implementor
725 * thereof), or if the field value cannot be
726 * converted to the type {@code double} by a
727 * widening conversion.
728 * @throws NullPointerException if the specified object is null
729 * and the field is an instance field.
730 * @throws ExceptionInInitializerError if the initialization provoked
731 * by this method fails.
732 * @see Field#get
733 */
734 @CallerSensitive
735 @ForceInline // to ensure Reflection.getCallerClass optimization
736 public double getDouble(Object obj)
737 throws IllegalArgumentException, IllegalAccessException
738 {
739 if (!override) {
740 Class<?> caller = Reflection.getCallerClass();
741 checkAccess(caller, obj);
742 return getFieldAccessor().getDouble(obj);
743 } else {
744 return getOverrideFieldAccessor().getDouble(obj);
745 }
746 }
747
748 /**
749 * Sets the field represented by this {@code Field} object on the
750 * specified object argument to the specified new value. The new
751 * value is automatically unwrapped if the underlying field has a
752 * primitive type.
753 *
754 * <p>The operation proceeds as follows:
755 *
756 * <p>If the underlying field is static, the {@code obj} argument is
757 * ignored; it may be null.
758 *
759 * <p>Otherwise the underlying field is an instance field. If the
760 * specified object argument is null, the method throws a
761 * {@code NullPointerException}. If the specified object argument is not
762 * an instance of the class or interface declaring the underlying
763 * field, the method throws an {@code IllegalArgumentException}.
764 *
765 * <p>If this {@code Field} object is enforcing Java language access control, and
766 * the underlying field is inaccessible, the method throws an
767 * {@code IllegalAccessException}.
768 *
769 * <p>If the underlying field is final, this {@code Field} object has
770 * <em>write</em> access if and only if the following conditions are met:
771 * <ul>
772 * <li>{@link #setAccessible(boolean) setAccessible(true)} has succeeded for
773 * this {@code Field} object;</li>
774 * <li>the field is non-static; and</li>
775 * <li>the field's declaring class is not a {@linkplain Class#isHidden()
776 * hidden class}; and</li>
777 * <li>the field's declaring class is not a {@linkplain Class#isRecord()
778 * record class}.</li>
779 * </ul>
780 * If any of the above checks is not met, this method throws an
781 * {@code IllegalAccessException}.
782 *
783 * <p> Setting a final field in this way
784 * is meaningful only during deserialization or reconstruction of
785 * instances of classes with blank final fields, before they are
786 * made available for access by other parts of a program. Use in
787 * any other context may have unpredictable effects, including cases
788 * in which other parts of a program continue to use the original
789 * value of this field.
790 *
791 * <p>If the underlying field is of a primitive type, an unwrapping
792 * conversion is attempted to convert the new value to a value of
793 * a primitive type. If this attempt fails, the method throws an
794 * {@code IllegalArgumentException}.
795 *
796 * <p>If, after possible unwrapping, the new value cannot be
797 * converted to the type of the underlying field by an identity or
798 * widening conversion, the method throws an
799 * {@code IllegalArgumentException}.
800 *
801 * <p>If the underlying field is static, the class that declared the
802 * field is initialized if it has not already been initialized.
803 *
804 * <p>The field is set to the possibly unwrapped and widened new value.
805 *
806 * <p>If the field is hidden in the type of {@code obj},
807 * the field's value is set according to the preceding rules.
808 *
809 * @param obj the object whose field should be modified
810 * @param value the new value for the field of {@code obj}
811 * being modified
812 *
813 * @throws IllegalAccessException if this {@code Field} object
814 * is enforcing Java language access control and the underlying
815 * field is inaccessible or final;
816 * or if this {@code Field} object has no write access.
817 * @throws IllegalArgumentException if the specified object is not an
818 * instance of the class or interface declaring the underlying
819 * field (or a subclass or implementor thereof),
820 * or if an unwrapping conversion fails.
821 * @throws NullPointerException if the specified object is null
822 * and the field is an instance field.
823 * @throws ExceptionInInitializerError if the initialization provoked
824 * by this method fails.
825 */
826 @CallerSensitive
827 @ForceInline // to ensure Reflection.getCallerClass optimization
828 public void set(Object obj, Object value)
829 throws IllegalArgumentException, IllegalAccessException
830 {
831 if (!override) {
832 Class<?> caller = Reflection.getCallerClass();
833 checkAccess(caller, obj);
834 getFieldAccessor().set(obj, value);
835 } else {
836 getOverrideFieldAccessor().set(obj, value);
837 }
838 }
839
840 /**
841 * Sets the value of a field as a {@code boolean} on the specified object.
842 * This method is equivalent to
843 * {@code set(obj, zObj)},
844 * where {@code zObj} is a {@code Boolean} object and
845 * {@code zObj.booleanValue() == z}.
846 *
847 * @param obj the object whose field should be modified
848 * @param z the new value for the field of {@code obj}
849 * being modified
850 *
851 * @throws IllegalAccessException if this {@code Field} object
852 * is enforcing Java language access control and the underlying
853 * field is either inaccessible or final;
854 * or if this {@code Field} object has no write access.
855 * @throws IllegalArgumentException if the specified object is not an
856 * instance of the class or interface declaring the underlying
857 * field (or a subclass or implementor thereof),
858 * or if an unwrapping conversion fails.
859 * @throws NullPointerException if the specified object is null
860 * and the field is an instance field.
861 * @throws ExceptionInInitializerError if the initialization provoked
862 * by this method fails.
863 * @see Field#set
864 */
865 @CallerSensitive
866 @ForceInline // to ensure Reflection.getCallerClass optimization
867 public void setBoolean(Object obj, boolean z)
868 throws IllegalArgumentException, IllegalAccessException
869 {
870 if (!override) {
871 Class<?> caller = Reflection.getCallerClass();
872 checkAccess(caller, obj);
873 getFieldAccessor().setBoolean(obj, z);
874 } else {
875 getOverrideFieldAccessor().setBoolean(obj, z);
876 }
877 }
878
879 /**
880 * Sets the value of a field as a {@code byte} on the specified object.
881 * This method is equivalent to
882 * {@code set(obj, bObj)},
883 * where {@code bObj} is a {@code Byte} object and
884 * {@code bObj.byteValue() == b}.
885 *
886 * @param obj the object whose field should be modified
887 * @param b the new value for the field of {@code obj}
888 * being modified
889 *
890 * @throws IllegalAccessException if this {@code Field} object
891 * is enforcing Java language access control and the underlying
892 * field is either inaccessible or final;
893 * or if this {@code Field} object has no write access.
894 * @throws IllegalArgumentException if the specified object is not an
895 * instance of the class or interface declaring the underlying
896 * field (or a subclass or implementor thereof),
897 * or if an unwrapping conversion fails.
898 * @throws NullPointerException if the specified object is null
899 * and the field is an instance field.
900 * @throws ExceptionInInitializerError if the initialization provoked
901 * by this method fails.
902 * @see Field#set
903 */
904 @CallerSensitive
905 @ForceInline // to ensure Reflection.getCallerClass optimization
906 public void setByte(Object obj, byte b)
907 throws IllegalArgumentException, IllegalAccessException
908 {
909 if (!override) {
910 Class<?> caller = Reflection.getCallerClass();
911 checkAccess(caller, obj);
912 getFieldAccessor().setByte(obj, b);
913 } else {
914 getOverrideFieldAccessor().setByte(obj, b);
915 }
916 }
917
918 /**
919 * Sets the value of a field as a {@code char} on the specified object.
920 * This method is equivalent to
921 * {@code set(obj, cObj)},
922 * where {@code cObj} is a {@code Character} object and
923 * {@code cObj.charValue() == c}.
924 *
925 * @param obj the object whose field should be modified
926 * @param c the new value for the field of {@code obj}
927 * being modified
928 *
929 * @throws IllegalAccessException if this {@code Field} object
930 * is enforcing Java language access control and the underlying
931 * field is either inaccessible or final;
932 * or if this {@code Field} object has no write access.
933 * @throws IllegalArgumentException if the specified object is not an
934 * instance of the class or interface declaring the underlying
935 * field (or a subclass or implementor thereof),
936 * or if an unwrapping conversion fails.
937 * @throws NullPointerException if the specified object is null
938 * and the field is an instance field.
939 * @throws ExceptionInInitializerError if the initialization provoked
940 * by this method fails.
941 * @see Field#set
942 */
943 @CallerSensitive
944 @ForceInline // to ensure Reflection.getCallerClass optimization
945 public void setChar(Object obj, char c)
946 throws IllegalArgumentException, IllegalAccessException
947 {
948 if (!override) {
949 Class<?> caller = Reflection.getCallerClass();
950 checkAccess(caller, obj);
951 getFieldAccessor().setChar(obj, c);
952 } else {
953 getOverrideFieldAccessor().setChar(obj, c);
954 }
955 }
956
957 /**
958 * Sets the value of a field as a {@code short} on the specified object.
959 * This method is equivalent to
960 * {@code set(obj, sObj)},
961 * where {@code sObj} is a {@code Short} object and
962 * {@code sObj.shortValue() == s}.
963 *
964 * @param obj the object whose field should be modified
965 * @param s the new value for the field of {@code obj}
966 * being modified
967 *
968 * @throws IllegalAccessException if this {@code Field} object
969 * is enforcing Java language access control and the underlying
970 * field is either inaccessible or final;
971 * or if this {@code Field} object has no write access.
972 * @throws IllegalArgumentException if the specified object is not an
973 * instance of the class or interface declaring the underlying
974 * field (or a subclass or implementor thereof),
975 * or if an unwrapping conversion fails.
976 * @throws NullPointerException if the specified object is null
977 * and the field is an instance field.
978 * @throws ExceptionInInitializerError if the initialization provoked
979 * by this method fails.
980 * @see Field#set
981 */
982 @CallerSensitive
983 @ForceInline // to ensure Reflection.getCallerClass optimization
984 public void setShort(Object obj, short s)
985 throws IllegalArgumentException, IllegalAccessException
986 {
987 if (!override) {
988 Class<?> caller = Reflection.getCallerClass();
989 checkAccess(caller, obj);
990 getFieldAccessor().setShort(obj, s);
991 } else {
992 getOverrideFieldAccessor().setShort(obj, s);
993 }
994 }
995
996 /**
997 * Sets the value of a field as an {@code int} on the specified object.
998 * This method is equivalent to
999 * {@code set(obj, iObj)},
1000 * where {@code iObj} is an {@code Integer} object and
1001 * {@code iObj.intValue() == i}.
1002 *
1003 * @param obj the object whose field should be modified
1004 * @param i the new value for the field of {@code obj}
1005 * being modified
1006 *
1007 * @throws IllegalAccessException if this {@code Field} object
1008 * is enforcing Java language access control and the underlying
1009 * field is either inaccessible or final;
1010 * or if this {@code Field} object has no write access.
1011 * @throws IllegalArgumentException if the specified object is not an
1012 * instance of the class or interface declaring the underlying
1013 * field (or a subclass or implementor thereof),
1014 * or if an unwrapping conversion fails.
1015 * @throws NullPointerException if the specified object is null
1016 * and the field is an instance field.
1017 * @throws ExceptionInInitializerError if the initialization provoked
1018 * by this method fails.
1019 * @see Field#set
1020 */
1021 @CallerSensitive
1022 @ForceInline // to ensure Reflection.getCallerClass optimization
1023 public void setInt(Object obj, int i)
1024 throws IllegalArgumentException, IllegalAccessException
1025 {
1026 if (!override) {
1027 Class<?> caller = Reflection.getCallerClass();
1028 checkAccess(caller, obj);
1029 getFieldAccessor().setInt(obj, i);
1030 } else {
1031 getOverrideFieldAccessor().setInt(obj, i);
1032 }
1033 }
1034
1035 /**
1036 * Sets the value of a field as a {@code long} on the specified object.
1037 * This method is equivalent to
1038 * {@code set(obj, lObj)},
1039 * where {@code lObj} is a {@code Long} object and
1040 * {@code lObj.longValue() == l}.
1041 *
1042 * @param obj the object whose field should be modified
1043 * @param l the new value for the field of {@code obj}
1044 * being modified
1045 *
1046 * @throws IllegalAccessException if this {@code Field} object
1047 * is enforcing Java language access control and the underlying
1048 * field is either inaccessible or final;
1049 * or if this {@code Field} object has no write access.
1050 * @throws IllegalArgumentException if the specified object is not an
1051 * instance of the class or interface declaring the underlying
1052 * field (or a subclass or implementor thereof),
1053 * or if an unwrapping conversion fails.
1054 * @throws NullPointerException if the specified object is null
1055 * and the field is an instance field.
1056 * @throws ExceptionInInitializerError if the initialization provoked
1057 * by this method fails.
1058 * @see Field#set
1059 */
1060 @CallerSensitive
1061 @ForceInline // to ensure Reflection.getCallerClass optimization
1062 public void setLong(Object obj, long l)
1063 throws IllegalArgumentException, IllegalAccessException
1064 {
1065 if (!override) {
1066 Class<?> caller = Reflection.getCallerClass();
1067 checkAccess(caller, obj);
1068 getFieldAccessor().setLong(obj, l);
1069 } else {
1070 getOverrideFieldAccessor().setLong(obj, l);
1071 }
1072 }
1073
1074 /**
1075 * Sets the value of a field as a {@code float} on the specified object.
1076 * This method is equivalent to
1077 * {@code set(obj, fObj)},
1078 * where {@code fObj} is a {@code Float} object and
1079 * {@code fObj.floatValue() == f}.
1080 *
1081 * @param obj the object whose field should be modified
1082 * @param f the new value for the field of {@code obj}
1083 * being modified
1084 *
1085 * @throws IllegalAccessException if this {@code Field} object
1086 * is enforcing Java language access control and the underlying
1087 * field is either inaccessible or final;
1088 * or if this {@code Field} object has no write access.
1089 * @throws IllegalArgumentException if the specified object is not an
1090 * instance of the class or interface declaring the underlying
1091 * field (or a subclass or implementor thereof),
1092 * or if an unwrapping conversion fails.
1093 * @throws NullPointerException if the specified object is null
1094 * and the field is an instance field.
1095 * @throws ExceptionInInitializerError if the initialization provoked
1096 * by this method fails.
1097 * @see Field#set
1098 */
1099 @CallerSensitive
1100 @ForceInline // to ensure Reflection.getCallerClass optimization
1101 public void setFloat(Object obj, float f)
1102 throws IllegalArgumentException, IllegalAccessException
1103 {
1104 if (!override) {
1105 Class<?> caller = Reflection.getCallerClass();
1106 checkAccess(caller, obj);
1107 getFieldAccessor().setFloat(obj, f);
1108 } else {
1109 getOverrideFieldAccessor().setFloat(obj, f);
1110 }
1111 }
1112
1113 /**
1114 * Sets the value of a field as a {@code double} on the specified object.
1115 * This method is equivalent to
1116 * {@code set(obj, dObj)},
1117 * where {@code dObj} is a {@code Double} object and
1118 * {@code dObj.doubleValue() == d}.
1119 *
1120 * @param obj the object whose field should be modified
1121 * @param d the new value for the field of {@code obj}
1122 * being modified
1123 *
1124 * @throws IllegalAccessException if this {@code Field} object
1125 * is enforcing Java language access control and the underlying
1126 * field is either inaccessible or final;
1127 * or if this {@code Field} object has no write access.
1128 * @throws IllegalArgumentException if the specified object is not an
1129 * instance of the class or interface declaring the underlying
1130 * field (or a subclass or implementor thereof),
1131 * or if an unwrapping conversion fails.
1132 * @throws NullPointerException if the specified object is null
1133 * and the field is an instance field.
1134 * @throws ExceptionInInitializerError if the initialization provoked
1135 * by this method fails.
1136 * @see Field#set
1137 */
1138 @CallerSensitive
1139 @ForceInline // to ensure Reflection.getCallerClass optimization
1140 public void setDouble(Object obj, double d)
1141 throws IllegalArgumentException, IllegalAccessException
1142 {
1143 if (!override) {
1144 Class<?> caller = Reflection.getCallerClass();
1145 checkAccess(caller, obj);
1146 getFieldAccessor().setDouble(obj, d);
1147 } else {
1148 getOverrideFieldAccessor().setDouble(obj, d);
1149 }
1150 }
1151
1152 // check access to field
1153 private void checkAccess(Class<?> caller, Object obj)
1154 throws IllegalAccessException
1155 {
1156 checkAccess(caller, clazz,
1157 Modifier.isStatic(modifiers) ? null : obj.getClass(),
1158 modifiers);
1159 }
1160
1161 // security check is done before calling this method
1162 private FieldAccessor getFieldAccessor() {
1163 FieldAccessor a = fieldAccessor;
1164 return (a != null) ? a : acquireFieldAccessor();
1165 }
1166
1167 private FieldAccessor getOverrideFieldAccessor() {
1168 FieldAccessor a = overrideFieldAccessor;
1169 return (a != null) ? a : acquireOverrideFieldAccessor();
1170 }
1171
1172 // NOTE that there is no synchronization used here. It is correct
1173 // (though not efficient) to generate more than one FieldAccessor
1174 // for a given Field. However, avoiding synchronization will
1175 // probably make the implementation more scalable.
1176 private FieldAccessor acquireFieldAccessor() {
1177 // First check to see if one has been created yet, and take it
1178 // if so
1179 Field root = this.root;
1180 FieldAccessor tmp = root == null ? null : root.fieldAccessor;
1181 if (tmp != null) {
1182 fieldAccessor = tmp;
1183 } else {
1184 // Otherwise fabricate one and propagate it up to the root
1185 tmp = reflectionFactory.newFieldAccessor(this, false);
1186 setFieldAccessor(tmp);
1187 }
1188 return tmp;
1189 }
1190
1191 private FieldAccessor acquireOverrideFieldAccessor() {
1192 // First check to see if one has been created yet, and take it
1193 // if so
1194 Field root = this.root;
1195 FieldAccessor tmp = root == null ? null : root.overrideFieldAccessor;
1196 if (tmp != null) {
1197 overrideFieldAccessor = tmp;
1198 } else {
1199 // Otherwise fabricate one and propagate it up to the root
1200 tmp = reflectionFactory.newFieldAccessor(this, true);
1201 setOverrideFieldAccessor(tmp);
1202 }
1203 return tmp;
1204 }
1205
1206 // Sets the fieldAccessor for this Field object and
1207 // (recursively) its root
1208 private void setFieldAccessor(FieldAccessor accessor) {
1209 fieldAccessor = accessor;
1210 // Propagate up
1211 Field root = this.root;
1212 if (root != null) {
1213 root.setFieldAccessor(accessor);
1214 }
1215 }
1216
1217 // Sets the overrideFieldAccessor for this Field object and
1218 // (recursively) its root
1219 private void setOverrideFieldAccessor(FieldAccessor accessor) {
1220 overrideFieldAccessor = accessor;
1221 // Propagate up
1222 Field root = this.root;
1223 if (root != null) {
1224 root.setOverrideFieldAccessor(accessor);
1225 }
1226 }
1227
1228 @Override
1229 /* package-private */ Field getRoot() {
1230 return root;
1231 }
1232
1233 /* package-private */ boolean isTrustedFinal() {
1234 return trustedFinal;
1235 }
1236
1237 /**
1238 * {@inheritDoc}
1239 *
1240 * @throws NullPointerException {@inheritDoc}
1241 * @since 1.5
1242 */
1243 @Override
1244 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
1245 Objects.requireNonNull(annotationClass);
1246 return annotationClass.cast(declaredAnnotations().get(annotationClass));
1247 }
1248
1249 /**
1250 * {@inheritDoc}
1251 *
1252 * @throws NullPointerException {@inheritDoc}
1253 * @since 1.8
1254 */
1255 @Override
1256 public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {
1257 Objects.requireNonNull(annotationClass);
1258
1259 return AnnotationSupport.getDirectlyAndIndirectlyPresent(declaredAnnotations(), annotationClass);
1260 }
1261
1262 /**
1263 * {@inheritDoc}
1264 */
1265 @Override
1266 public Annotation[] getDeclaredAnnotations() {
1267 return AnnotationParser.toArray(declaredAnnotations());
1268 }
1269
1270 private transient volatile Map<Class<? extends Annotation>, Annotation> declaredAnnotations;
1271
1272 private Map<Class<? extends Annotation>, Annotation> declaredAnnotations() {
1273 Map<Class<? extends Annotation>, Annotation> declAnnos;
1274 if ((declAnnos = declaredAnnotations) == null) {
1275 synchronized (this) {
1276 if ((declAnnos = declaredAnnotations) == null) {
1277 Field root = this.root;
1278 if (root != null) {
1279 declAnnos = root.declaredAnnotations();
1280 } else {
1281 declAnnos = AnnotationParser.parseAnnotations(
1282 annotations,
1283 SharedSecrets.getJavaLangAccess()
1284 .getConstantPool(getDeclaringClass()),
1285 getDeclaringClass());
1286 }
1287 declaredAnnotations = declAnnos;
1288 }
1289 }
1290 }
1291 return declAnnos;
1292 }
1293
1294 private native byte[] getTypeAnnotationBytes0();
1295
1296 /**
1297 * Returns an AnnotatedType object that represents the use of a type to specify
1298 * the declared type of the field represented by this Field.
1299 * @return an object representing the declared type of the field
1300 * represented by this Field
1301 *
1302 * @since 1.8
1303 */
1304 public AnnotatedType getAnnotatedType() {
1305 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
1306 SharedSecrets.getJavaLangAccess().
1307 getConstantPool(getDeclaringClass()),
1308 this,
1309 getDeclaringClass(),
1310 getGenericType(),
1311 TypeAnnotation.TypeAnnotationTarget.FIELD);
1312 }
1313 }