1 /*
2 * Copyright (c) 1996, 2022, 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.value.PrimitiveClass;
30 import jdk.internal.misc.VM;
31 import jdk.internal.reflect.CallerSensitive;
32 import jdk.internal.reflect.ConstructorAccessor;
33 import jdk.internal.reflect.Reflection;
34 import jdk.internal.vm.annotation.ForceInline;
35 import jdk.internal.vm.annotation.Stable;
36 import sun.reflect.annotation.TypeAnnotation;
37 import sun.reflect.annotation.TypeAnnotationParser;
38 import sun.reflect.generics.repository.ConstructorRepository;
39 import sun.reflect.generics.repository.GenericDeclRepository;
40 import sun.reflect.generics.factory.CoreReflectionFactory;
41 import sun.reflect.generics.factory.GenericsFactory;
42 import sun.reflect.generics.scope.ConstructorScope;
43 import java.lang.annotation.Annotation;
44 import java.lang.annotation.AnnotationFormatError;
45 import java.util.StringJoiner;
46
47 /**
48 * {@code Constructor} provides information about, and access to, a single
49 * constructor for a class.
50 *
51 * <p>{@code Constructor} permits widening conversions to occur when matching the
52 * actual parameters to newInstance() with the underlying
53 * constructor's formal parameters, but throws an
54 * {@code IllegalArgumentException} if a narrowing conversion would occur.
55 *
56 * @param <T> the class in which the constructor is declared
57 *
58 * @see Member
59 * @see java.lang.Class
60 * @see java.lang.Class#getConstructors()
61 * @see java.lang.Class#getConstructor(Class[])
62 * @see java.lang.Class#getDeclaredConstructors()
63 *
64 * @author Kenneth Russell
65 * @author Nakul Saraiya
66 * @since 1.1
67 */
68 public final class Constructor<T> extends Executable {
69 private final Class<T> clazz;
70 private final int slot;
71 private final Class<?>[] parameterTypes;
72 private final Class<?>[] exceptionTypes;
73 private final int modifiers;
74 // Generics and annotations support
75 private final transient String signature;
76 // generic info repository; lazily initialized
77 private transient ConstructorRepository genericInfo;
78 private final byte[] annotations;
79 private final byte[] parameterAnnotations;
80
81 // Generics infrastructure
82 // Accessor for factory
83 private GenericsFactory getFactory() {
84 // create scope and factory
85 return CoreReflectionFactory.make(this, ConstructorScope.make(this));
86 }
87
88 // Accessor for generic info repository
89 @Override
90 ConstructorRepository getGenericInfo() {
91 // lazily initialize repository if necessary
92 if (genericInfo == null) {
93 // create and cache generic info repository
94 genericInfo =
95 ConstructorRepository.make(getSignature(),
96 getFactory());
97 }
98 return genericInfo; //return cached repository
99 }
100
101 @Stable
102 private ConstructorAccessor constructorAccessor;
103 // For sharing of ConstructorAccessors. This branching structure
104 // is currently only two levels deep (i.e., one root Constructor
105 // and potentially many Constructor objects pointing to it.)
106 //
107 // If this branching structure would ever contain cycles, deadlocks can
108 // occur in annotation code.
109 private Constructor<T> root;
110
111 @Override
112 Constructor<T> getRoot() {
113 return root;
114 }
115
116 /**
117 * Package-private constructor used by ReflectAccess to enable
118 * instantiation of these objects in Java code from the java.lang
119 * package via jdk.internal.access.JavaLangReflectAccess.
120 */
121 Constructor(Class<T> declaringClass,
122 Class<?>[] parameterTypes,
123 Class<?>[] checkedExceptions,
124 int modifiers,
125 int slot,
126 String signature,
127 byte[] annotations,
128 byte[] parameterAnnotations) {
129 assert PrimitiveClass.isPrimaryType(declaringClass);
130 this.clazz = declaringClass;
131 this.parameterTypes = parameterTypes;
132 this.exceptionTypes = checkedExceptions;
133 this.modifiers = modifiers;
134 this.slot = slot;
135 this.signature = signature;
136 this.annotations = annotations;
137 this.parameterAnnotations = parameterAnnotations;
138 }
139
140 /**
141 * Package-private routine (exposed to java.lang.Class via
142 * ReflectAccess) which returns a copy of this Constructor. The copy's
143 * "root" field points to this Constructor.
144 */
145 Constructor<T> copy() {
146 // This routine enables sharing of ConstructorAccessor objects
147 // among Constructor objects which refer to the same underlying
148 // method in the VM. (All of this contortion is only necessary
149 // because of the "accessibility" bit in AccessibleObject,
150 // which implicitly requires that new java.lang.reflect
151 // objects be fabricated for each reflective call on Class
152 // objects.)
153 if (this.root != null)
154 throw new IllegalArgumentException("Can not copy a non-root Constructor");
155
156 Constructor<T> res = new Constructor<>(clazz,
157 parameterTypes,
158 exceptionTypes, modifiers, slot,
159 signature,
160 annotations,
161 parameterAnnotations);
162 res.root = this;
163 // Might as well eagerly propagate this if already present
164 res.constructorAccessor = constructorAccessor;
165 return res;
166 }
167
168 /**
169 * {@inheritDoc}
170 *
171 * <p> A {@code SecurityException} is also thrown if this object is a
172 * {@code Constructor} object for the class {@code Class} and {@code flag}
173 * is true. </p>
174 *
175 * @param flag {@inheritDoc}
176 *
177 * @throws InaccessibleObjectException {@inheritDoc}
178 * @throws SecurityException if the request is denied by the security manager
179 * or this is a constructor for {@code java.lang.Class}
180 *
181 */
182 @Override
183 @CallerSensitive
184 public void setAccessible(boolean flag) {
185 AccessibleObject.checkPermission();
186 if (flag) {
187 checkCanSetAccessible(Reflection.getCallerClass());
188 }
189 setAccessible0(flag);
190 }
191
192 @Override
193 void checkCanSetAccessible(Class<?> caller) {
194 checkCanSetAccessible(caller, clazz);
195 if (clazz == Class.class) {
196 // can we change this to InaccessibleObjectException?
197 throw new SecurityException("Cannot make a java.lang.Class"
198 + " constructor accessible");
199 }
200 }
201
202 @Override
203 boolean hasGenericInformation() {
204 return (getSignature() != null);
205 }
206
207 @Override
208 byte[] getAnnotationBytes() {
209 return annotations;
210 }
211
212 /**
213 * Returns the {@code Class} object representing the class that
214 * declares the constructor represented by this object.
215 */
216 @Override
217 public Class<T> getDeclaringClass() {
218 return clazz;
219 }
220
221 /**
222 * Returns the name of this constructor, as a string. This is
223 * the binary name of the constructor's declaring class.
224 */
225 @Override
226 public String getName() {
227 return getDeclaringClass().getName();
228 }
229
230 /**
231 * {@inheritDoc}
232 * @jls 8.8.3 Constructor Modifiers
233 */
234 @Override
235 public int getModifiers() {
236 return modifiers;
237 }
238
239 /**
240 * {@inheritDoc}
241 * @throws GenericSignatureFormatError {@inheritDoc}
242 * @since 1.5
243 */
244 @Override
245 @SuppressWarnings({"rawtypes", "unchecked"})
246 public TypeVariable<Constructor<T>>[] getTypeParameters() {
247 if (getSignature() != null) {
248 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
249 } else
250 return (TypeVariable<Constructor<T>>[])GenericDeclRepository.EMPTY_TYPE_VARS;
251 }
252
253
254 @Override
255 Class<?>[] getSharedParameterTypes() {
256 return parameterTypes;
257 }
258
259 @Override
260 Class<?>[] getSharedExceptionTypes() {
261 return exceptionTypes;
262 }
263
264 /**
265 * {@inheritDoc}
266 */
267 @Override
268 public Class<?>[] getParameterTypes() {
269 return parameterTypes.clone();
270 }
271
272 /**
273 * {@inheritDoc}
274 * @since 1.8
275 */
276 public int getParameterCount() { return parameterTypes.length; }
277
278 /**
279 * {@inheritDoc}
280 * @throws GenericSignatureFormatError {@inheritDoc}
281 * @throws TypeNotPresentException {@inheritDoc}
282 * @throws MalformedParameterizedTypeException {@inheritDoc}
283 * @since 1.5
284 */
285 @Override
286 public Type[] getGenericParameterTypes() {
287 return super.getGenericParameterTypes();
288 }
289
290 /**
291 * {@inheritDoc}
292 */
293 @Override
294 public Class<?>[] getExceptionTypes() {
295 return exceptionTypes.clone();
296 }
297
298
299 /**
300 * {@inheritDoc}
301 * @throws GenericSignatureFormatError {@inheritDoc}
302 * @throws TypeNotPresentException {@inheritDoc}
303 * @throws MalformedParameterizedTypeException {@inheritDoc}
304 * @since 1.5
305 */
306 @Override
307 public Type[] getGenericExceptionTypes() {
308 return super.getGenericExceptionTypes();
309 }
310
311 /**
312 * Compares this {@code Constructor} against the specified object.
313 * Returns true if the objects are the same. Two {@code Constructor} objects are
314 * the same if they were declared by the same class and have the
315 * same formal parameter types.
316 */
317 public boolean equals(Object obj) {
318 if (obj instanceof Constructor<?> other) {
319 if (getDeclaringClass() == other.getDeclaringClass()) {
320 return equalParamTypes(parameterTypes, other.parameterTypes);
321 }
322 }
323 return false;
324 }
325
326 /**
327 * Returns a hashcode for this {@code Constructor}. The hashcode is
328 * the same as the hashcode for the underlying constructor's
329 * declaring class name.
330 */
331 public int hashCode() {
332 return getDeclaringClass().getName().hashCode();
333 }
334
335 /**
336 * Returns a string describing this {@code Constructor}. The string is
337 * formatted as the constructor access modifiers, if any,
338 * followed by the fully-qualified name of the declaring class,
339 * followed by a parenthesized, comma-separated list of the
340 * constructor's formal parameter types. For example:
341 * <pre>{@code
342 * public java.util.HashMap(int,float)
343 * }</pre>
344 *
345 * <p>If the constructor is declared to throw exceptions, the
346 * parameter list is followed by a space, followed by the word
347 * "{@code throws}" followed by a comma-separated list of the
348 * thrown exception types.
349 *
350 * <p>The only possible modifiers for constructors are the access
351 * modifiers {@code public}, {@code protected} or
352 * {@code private}. Only one of these may appear, or none if the
353 * constructor has default (package) access.
354 *
355 * @return a string describing this {@code Constructor}
356 * @jls 8.8.3 Constructor Modifiers
357 * @jls 8.9.2 Enum Body Declarations
358 */
359 public String toString() {
360 return sharedToString(Modifier.constructorModifiers(),
361 false,
362 parameterTypes,
363 exceptionTypes);
364 }
365
366 @Override
367 void specificToStringHeader(StringBuilder sb) {
368 sb.append(getDeclaringClassTypeName());
369 }
370
371 @Override
372 String toShortString() {
373 StringBuilder sb = new StringBuilder("constructor ");
374 sb.append(getDeclaringClassTypeName());
375 sb.append('(');
376 StringJoiner sj = new StringJoiner(",");
377 for (Class<?> parameterType : getSharedParameterTypes()) {
378 sj.add(parameterType.getTypeName());
379 }
380 sb.append(sj);
381 sb.append(')');
382 return sb.toString();
383 }
384
385 /**
386 * Returns a string describing this {@code Constructor},
387 * including type parameters. The string is formatted as the
388 * constructor access modifiers, if any, followed by an
389 * angle-bracketed comma separated list of the constructor's type
390 * parameters, if any, including informative bounds of the
391 * type parameters, if any, followed by the fully-qualified name of the
392 * declaring class, followed by a parenthesized, comma-separated
393 * list of the constructor's generic formal parameter types.
394 *
395 * If this constructor was declared to take a variable number of
396 * arguments, instead of denoting the last parameter as
397 * "<code><i>Type</i>[]</code>", it is denoted as
398 * "<code><i>Type</i>...</code>".
399 *
400 * A space is used to separate access modifiers from one another
401 * and from the type parameters or class name. If there are no
402 * type parameters, the type parameter list is elided; if the type
403 * parameter list is present, a space separates the list from the
404 * class name. If the constructor is declared to throw
405 * exceptions, the parameter list is followed by a space, followed
406 * by the word "{@code throws}" followed by a
407 * comma-separated list of the generic thrown exception types.
408 *
409 * <p>The only possible modifiers for constructors are the access
410 * modifiers {@code public}, {@code protected} or
411 * {@code private}. Only one of these may appear, or none if the
412 * constructor has default (package) access.
413 *
414 * @return a string describing this {@code Constructor},
415 * include type parameters
416 *
417 * @since 1.5
418 * @jls 8.8.3 Constructor Modifiers
419 * @jls 8.9.2 Enum Body Declarations
420 */
421 @Override
422 public String toGenericString() {
423 return sharedToGenericString(Modifier.constructorModifiers(), false);
424 }
425
426 @Override
427 void specificToGenericStringHeader(StringBuilder sb) {
428 specificToStringHeader(sb);
429 }
430
431 /**
432 * Uses the constructor represented by this {@code Constructor} object to
433 * create and initialize a new instance of the constructor's
434 * declaring class, with the specified initialization parameters.
435 * Individual parameters are automatically unwrapped to match
436 * primitive formal parameters, and both primitive and reference
437 * parameters are subject to method invocation conversions as necessary.
438 *
439 * <p>If the number of formal parameters required by the underlying constructor
440 * is 0, the supplied {@code initargs} array may be of length 0 or null.
441 *
442 * <p>If the constructor's declaring class is an inner class in a
443 * non-static context, the first argument to the constructor needs
444 * to be the enclosing instance; see section {@jls 15.9.3} of
445 * <cite>The Java Language Specification</cite>.
446 *
447 * <p>If the required access and argument checks succeed and the
448 * instantiation will proceed, the constructor's declaring class
449 * is initialized if it has not already been initialized.
450 *
451 * <p>If the constructor completes normally, returns the newly
452 * created and initialized instance.
453 *
454 * @param initargs array of objects to be passed as arguments to
455 * the constructor call; values of primitive types are wrapped in
456 * a wrapper object of the appropriate type (e.g. a {@code float}
457 * in a {@link java.lang.Float Float})
458 *
459 * @return a new object created by calling the constructor
460 * this object represents
461 *
462 * @throws IllegalAccessException if this {@code Constructor} object
463 * is enforcing Java language access control and the underlying
464 * constructor is inaccessible.
465 * @throws IllegalArgumentException if the number of actual
466 * and formal parameters differ; if an unwrapping
467 * conversion for primitive arguments fails; or if,
468 * after possible unwrapping, a parameter value
469 * cannot be converted to the corresponding formal
470 * parameter type by a method invocation conversion; if
471 * this constructor pertains to an enum class.
472 * @throws InstantiationException if the class that declares the
473 * underlying constructor represents an abstract class.
474 * @throws InvocationTargetException if the underlying constructor
475 * throws an exception.
476 * @throws ExceptionInInitializerError if the initialization provoked
477 * by this method fails.
478 */
479 @CallerSensitive
480 @ForceInline // to ensure Reflection.getCallerClass optimization
481 public T newInstance(Object ... initargs)
482 throws InstantiationException, IllegalAccessException,
483 IllegalArgumentException, InvocationTargetException
484 {
485 Class<?> caller = override ? null : Reflection.getCallerClass();
486 return newInstanceWithCaller(initargs, !override, caller);
487 }
488
489 /* package-private */
490 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller)
491 throws InstantiationException, IllegalAccessException,
492 InvocationTargetException
493 {
494 if (checkAccess)
495 checkAccess(caller, clazz, clazz, modifiers);
496
497 ConstructorAccessor ca = constructorAccessor; // read @Stable
498 if (ca == null) {
499 ca = acquireConstructorAccessor();
500 }
501 @SuppressWarnings("unchecked")
502 T inst = (T) ca.newInstance(args);
503 return inst;
504 }
505
506 /**
507 * {@inheritDoc}
508 * @since 1.5
509 * @jls 8.4.1 Formal Parameters
510 */
511 @Override
512 public boolean isVarArgs() {
513 return super.isVarArgs();
514 }
515
516 /**
517 * {@inheritDoc}
518 * @jls 13.1 The Form of a Binary
519 * @jvms 4.6 Methods
520 * @since 1.5
521 * @see <a
522 * href="{@docRoot}/java.base/java/lang/reflect/package-summary.html#LanguageJvmModel">Java
523 * programming language and JVM modeling in core reflection</a>
524 */
525 @Override
526 public boolean isSynthetic() {
527 return super.isSynthetic();
528 }
529
530 // NOTE that there is no synchronization used here. It is correct
531 // (though not efficient) to generate more than one
532 // ConstructorAccessor for a given Constructor. However, avoiding
533 // synchronization will probably make the implementation more
534 // scalable.
535 private ConstructorAccessor acquireConstructorAccessor() {
536
537 // First check to see if one has been created yet, and take it
538 // if so.
539 Constructor<?> root = this.root;
540 ConstructorAccessor tmp = root == null ? null : root.getConstructorAccessor();
541 if (tmp != null) {
542 constructorAccessor = tmp;
543 } else {
544 // Otherwise fabricate one and propagate it up to the root
545 // Ensure the declaring class is not an Enum class.
546 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
547 throw new IllegalArgumentException("Cannot reflectively create enum objects");
548
549 tmp = reflectionFactory.newConstructorAccessor(this);
550 // set the constructor accessor only if it's not using native implementation
551 if (VM.isJavaLangInvokeInited())
552 setConstructorAccessor(tmp);
553 }
554
555 return tmp;
556 }
557
558 // Returns ConstructorAccessor for this Constructor object, not
559 // looking up the chain to the root
560 ConstructorAccessor getConstructorAccessor() {
561 return constructorAccessor;
562 }
563
564 // Sets the ConstructorAccessor for this Constructor object and
565 // (recursively) its root
566 void setConstructorAccessor(ConstructorAccessor accessor) {
567 constructorAccessor = accessor;
568 // Propagate up
569 Constructor<?> root = this.root;
570 if (root != null) {
571 root.setConstructorAccessor(accessor);
572 }
573 }
574
575 int getSlot() {
576 return slot;
577 }
578
579 String getSignature() {
580 return signature;
581 }
582
583 byte[] getRawAnnotations() {
584 return annotations;
585 }
586
587 byte[] getRawParameterAnnotations() {
588 return parameterAnnotations;
589 }
590
591
592 /**
593 * {@inheritDoc}
594 *
595 * @throws NullPointerException {@inheritDoc}
596 * @since 1.5
597 */
598 @Override
599 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
600 return super.getAnnotation(annotationClass);
601 }
602
603 /**
604 * {@inheritDoc}
605 * @since 1.5
606 */
607 @Override
608 public Annotation[] getDeclaredAnnotations() {
609 return super.getDeclaredAnnotations();
610 }
611
612 /**
613 * {@inheritDoc}
614 * @since 1.5
615 */
616 @Override
617 public Annotation[][] getParameterAnnotations() {
618 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
619 }
620
621 @Override
622 boolean handleParameterNumberMismatch(int resultLength, Class<?>[] parameterTypes) {
623 int numParameters = parameterTypes.length;
624 Class<?> declaringClass = getDeclaringClass();
625 if (declaringClass.isEnum()) {
626 return resultLength + 2 == numParameters &&
627 parameterTypes[0] == String.class &&
628 parameterTypes[1] == int.class;
629 } else if (
630 declaringClass.isAnonymousClass() ||
631 declaringClass.isLocalClass() )
632 return false; // Can't do reliable parameter counting
633 else {
634 if (declaringClass.isMemberClass() &&
635 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
636 resultLength + 1 == numParameters) {
637 return true;
638 } else {
639 throw new AnnotationFormatError(
640 "Parameter annotations don't match number of parameters");
641 }
642 }
643 }
644
645 /**
646 * {@inheritDoc}
647 * @since 1.8
648 */
649 @Override
650 public AnnotatedType getAnnotatedReturnType() {
651 return getAnnotatedReturnType0(getDeclaringClass());
652 }
653
654 /**
655 * {@inheritDoc}
656 * @since 1.8
657 */
658 @Override
659 public AnnotatedType getAnnotatedReceiverType() {
660 Class<?> thisDeclClass = getDeclaringClass();
661 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
662
663 if (enclosingClass == null) {
664 // A Constructor for a top-level class
665 return null;
666 }
667
668 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
669 if (outerDeclaringClass == null) {
670 // A constructor for a local or anonymous class
671 return null;
672 }
673
674 // Either static nested or inner class
675 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
676 // static nested
677 return null;
678 }
679
680 // A Constructor for an inner class
681 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
682 SharedSecrets.getJavaLangAccess().
683 getConstantPool(thisDeclClass),
684 this,
685 thisDeclClass,
686 parameterize(enclosingClass),
687 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
688 }
689 }