1 /*
2 * Copyright (c) 1996, 2018, 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.ConstructorAccessor;
31 import jdk.internal.reflect.Reflection;
32 import jdk.internal.vm.annotation.ForceInline;
33 import sun.reflect.annotation.TypeAnnotation;
34 import sun.reflect.annotation.TypeAnnotationParser;
35 import sun.reflect.generics.repository.ConstructorRepository;
36 import sun.reflect.generics.factory.CoreReflectionFactory;
37 import sun.reflect.generics.factory.GenericsFactory;
38 import sun.reflect.generics.scope.ConstructorScope;
39 import java.lang.annotation.Annotation;
40 import java.lang.annotation.AnnotationFormatError;
41 import java.util.StringJoiner;
42
43 /**
44 * {@code Constructor} provides information about, and access to, a single
45 * constructor for a class.
46 *
47 * <p>{@code Constructor} permits widening conversions to occur when matching the
48 * actual parameters to newInstance() with the underlying
49 * constructor's formal parameters, but throws an
50 * {@code IllegalArgumentException} if a narrowing conversion would occur.
51 *
52 * @param <T> the class in which the constructor is declared
53 *
54 * @see Member
55 * @see java.lang.Class
56 * @see java.lang.Class#getConstructors()
57 * @see java.lang.Class#getConstructor(Class[])
58 * @see java.lang.Class#getDeclaredConstructors()
59 *
60 * @author Kenneth Russell
61 * @author Nakul Saraiya
62 * @since 1.1
63 */
64 public final class Constructor<T> extends Executable {
65 private Class<T> clazz;
66 private int slot;
67 private Class<?>[] parameterTypes;
68 private Class<?>[] exceptionTypes;
69 private int modifiers;
70 // Generics and annotations support
71 private transient String signature;
72 // generic info repository; lazily initialized
73 private transient ConstructorRepository genericInfo;
74 private byte[] annotations;
75 private byte[] parameterAnnotations;
76
77 // Generics infrastructure
78 // Accessor for factory
79 private GenericsFactory getFactory() {
80 // create scope and factory
81 return CoreReflectionFactory.make(this, ConstructorScope.make(this));
82 }
83
84 // Accessor for generic info repository
85 @Override
86 ConstructorRepository getGenericInfo() {
87 // lazily initialize repository if necessary
88 if (genericInfo == null) {
89 // create and cache generic info repository
90 genericInfo =
91 ConstructorRepository.make(getSignature(),
92 getFactory());
93 }
94 return genericInfo; //return cached repository
95 }
96
97 private volatile ConstructorAccessor constructorAccessor;
98 // For sharing of ConstructorAccessors. This branching structure
99 // is currently only two levels deep (i.e., one root Constructor
100 // and potentially many Constructor objects pointing to it.)
101 //
102 // If this branching structure would ever contain cycles, deadlocks can
103 // occur in annotation code.
104 private Constructor<T> root;
105
106 @Override
107 Constructor<T> getRoot() {
108 return root;
109 }
110
111 /**
112 * Package-private constructor used by ReflectAccess to enable
113 * instantiation of these objects in Java code from the java.lang
114 * package via sun.reflect.LangReflectAccess.
115 */
116 Constructor(Class<T> declaringClass,
117 Class<?>[] parameterTypes,
118 Class<?>[] checkedExceptions,
119 int modifiers,
120 int slot,
121 String signature,
122 byte[] annotations,
123 byte[] parameterAnnotations) {
124 this.clazz = declaringClass;
125 this.parameterTypes = parameterTypes;
126 this.exceptionTypes = checkedExceptions;
127 this.modifiers = modifiers;
128 this.slot = slot;
129 this.signature = signature;
130 this.annotations = annotations;
131 this.parameterAnnotations = parameterAnnotations;
132 }
133
134 /**
135 * Package-private routine (exposed to java.lang.Class via
136 * ReflectAccess) which returns a copy of this Constructor. The copy's
137 * "root" field points to this Constructor.
138 */
139 Constructor<T> copy() {
140 // This routine enables sharing of ConstructorAccessor objects
141 // among Constructor objects which refer to the same underlying
142 // method in the VM. (All of this contortion is only necessary
143 // because of the "accessibility" bit in AccessibleObject,
144 // which implicitly requires that new java.lang.reflect
145 // objects be fabricated for each reflective call on Class
146 // objects.)
147 if (this.root != null)
148 throw new IllegalArgumentException("Can not copy a non-root Constructor");
149
150 Constructor<T> res = new Constructor<>(clazz,
151 parameterTypes,
152 exceptionTypes, modifiers, slot,
153 signature,
154 annotations,
155 parameterAnnotations);
156 res.root = this;
157 // Might as well eagerly propagate this if already present
158 res.constructorAccessor = constructorAccessor;
159 return res;
160 }
161
162 /**
163 * {@inheritDoc}
164 *
165 * <p> A {@code SecurityException} is also thrown if this object is a
166 * {@code Constructor} object for the class {@code Class} and {@code flag}
167 * is true. </p>
168 *
169 * @param flag {@inheritDoc}
170 *
171 * @throws InaccessibleObjectException {@inheritDoc}
172 * @throws SecurityException if the request is denied by the security manager
173 * or this is a constructor for {@code java.lang.Class}
174 *
175 * @spec JPMS
176 */
177 @Override
178 @CallerSensitive
179 public void setAccessible(boolean flag) {
180 AccessibleObject.checkPermission();
181
182 if (flag) {
183 checkCanSetAccessible(Reflection.getCallerClass());
184 }
185 setAccessible0(flag);
186 }
187
188 @Override
189 void checkCanSetAccessible(Class<?> caller) {
190 checkCanSetAccessible(caller, clazz);
191 if (clazz == Class.class) {
192 // can we change this to InaccessibleObjectException?
193 throw new SecurityException("Cannot make a java.lang.Class"
194 + " constructor accessible");
195 }
196 }
197
198 @Override
199 boolean hasGenericInformation() {
200 return (getSignature() != null);
201 }
202
203 @Override
204 byte[] getAnnotationBytes() {
205 return annotations;
206 }
207
208 /**
209 * Returns the {@code Class} object representing the class that
210 * declares the constructor represented by this object.
211 */
212 @Override
213 public Class<T> getDeclaringClass() {
214 return clazz;
215 }
216
217 /**
218 * Returns the name of this constructor, as a string. This is
219 * the binary name of the constructor's declaring class.
220 */
221 @Override
222 public String getName() {
223 return getDeclaringClass().getName();
224 }
225
226 /**
227 * {@inheritDoc}
228 */
229 @Override
230 public int getModifiers() {
231 return modifiers;
232 }
233
234 /**
235 * {@inheritDoc}
236 * @throws GenericSignatureFormatError {@inheritDoc}
237 * @since 1.5
238 */
239 @Override
240 @SuppressWarnings({"rawtypes", "unchecked"})
241 public TypeVariable<Constructor<T>>[] getTypeParameters() {
242 if (getSignature() != null) {
243 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
244 } else
245 return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
246 }
247
248
249 @Override
250 Class<?>[] getSharedParameterTypes() {
251 return parameterTypes;
252 }
253
254 @Override
255 Class<?>[] getSharedExceptionTypes() {
256 return exceptionTypes;
257 }
258
259 /**
260 * {@inheritDoc}
261 */
262 @Override
263 public Class<?>[] getParameterTypes() {
264 return parameterTypes.clone();
265 }
266
267 /**
268 * {@inheritDoc}
269 * @since 1.8
270 */
271 public int getParameterCount() { return parameterTypes.length; }
272
273 /**
274 * {@inheritDoc}
275 * @throws GenericSignatureFormatError {@inheritDoc}
276 * @throws TypeNotPresentException {@inheritDoc}
277 * @throws MalformedParameterizedTypeException {@inheritDoc}
278 * @since 1.5
279 */
280 @Override
281 public Type[] getGenericParameterTypes() {
282 return super.getGenericParameterTypes();
283 }
284
285 /**
286 * {@inheritDoc}
287 */
288 @Override
289 public Class<?>[] getExceptionTypes() {
290 return exceptionTypes.clone();
291 }
292
293
294 /**
295 * {@inheritDoc}
296 * @throws GenericSignatureFormatError {@inheritDoc}
297 * @throws TypeNotPresentException {@inheritDoc}
298 * @throws MalformedParameterizedTypeException {@inheritDoc}
299 * @since 1.5
300 */
301 @Override
302 public Type[] getGenericExceptionTypes() {
303 return super.getGenericExceptionTypes();
304 }
305
306 /**
307 * Compares this {@code Constructor} against the specified object.
308 * Returns true if the objects are the same. Two {@code Constructor} objects are
309 * the same if they were declared by the same class and have the
310 * same formal parameter types.
311 */
312 public boolean equals(Object obj) {
313 if (obj != null && obj instanceof Constructor) {
314 Constructor<?> other = (Constructor<?>)obj;
315 if (getDeclaringClass() == other.getDeclaringClass()) {
316 return equalParamTypes(parameterTypes, other.parameterTypes);
317 }
318 }
319 return false;
320 }
321
322 /**
323 * Returns a hashcode for this {@code Constructor}. The hashcode is
324 * the same as the hashcode for the underlying constructor's
325 * declaring class name.
326 */
327 public int hashCode() {
328 return getDeclaringClass().getName().hashCode();
329 }
330
331 /**
332 * Returns a string describing this {@code Constructor}. The string is
333 * formatted as the constructor access modifiers, if any,
334 * followed by the fully-qualified name of the declaring class,
335 * followed by a parenthesized, comma-separated list of the
336 * constructor's formal parameter types. For example:
337 * <pre>{@code
338 * public java.util.Hashtable(int,float)
339 * }</pre>
340 *
341 * <p>If the constructor is declared to throw exceptions, the
342 * parameter list is followed by a space, followed by the word
343 * "{@code throws}" followed by a comma-separated list of the
344 * thrown exception types.
345 *
346 * <p>The only possible modifiers for constructors are the access
347 * modifiers {@code public}, {@code protected} or
348 * {@code private}. Only one of these may appear, or none if the
349 * constructor has default (package) access.
350 *
351 * @return a string describing this {@code Constructor}
352 * @jls 8.8.3 Constructor Modifiers
353 * @jls 8.9.2 Enum Body Declarations
354 */
355 public String toString() {
356 return sharedToString(Modifier.constructorModifiers(),
357 false,
358 parameterTypes,
359 exceptionTypes);
360 }
361
362 @Override
363 void specificToStringHeader(StringBuilder sb) {
364 sb.append(getDeclaringClass().getTypeName());
365 }
366
367 @Override
368 String toShortString() {
369 StringBuilder sb = new StringBuilder("constructor ");
370 sb.append(getDeclaringClass().getTypeName());
371 sb.append('(');
372 StringJoiner sj = new StringJoiner(",");
373 for (Class<?> parameterType : getParameterTypes()) {
374 sj.add(parameterType.getTypeName());
375 }
376 sb.append(sj);
377 sb.append(')');
378 return sb.toString();
379 }
380
381 /**
382 * Returns a string describing this {@code Constructor},
383 * including type parameters. The string is formatted as the
384 * constructor access modifiers, if any, followed by an
385 * angle-bracketed comma separated list of the constructor's type
386 * parameters, if any, including informative bounds of the
387 * type parameters, if any, followed by the fully-qualified name of the
388 * declaring class, followed by a parenthesized, comma-separated
389 * list of the constructor's generic formal parameter types.
390 *
391 * If this constructor was declared to take a variable number of
392 * arguments, instead of denoting the last parameter as
393 * "<code><i>Type</i>[]</code>", it is denoted as
394 * "<code><i>Type</i>...</code>".
395 *
396 * A space is used to separate access modifiers from one another
397 * and from the type parameters or class name. If there are no
398 * type parameters, the type parameter list is elided; if the type
399 * parameter list is present, a space separates the list from the
400 * class name. If the constructor is declared to throw
401 * exceptions, the parameter list is followed by a space, followed
402 * by the word "{@code throws}" followed by a
403 * comma-separated list of the generic thrown exception types.
404 *
405 * <p>The only possible modifiers for constructors are the access
406 * modifiers {@code public}, {@code protected} or
407 * {@code private}. Only one of these may appear, or none if the
408 * constructor has default (package) access.
409 *
410 * @return a string describing this {@code Constructor},
411 * include type parameters
412 *
413 * @since 1.5
414 * @jls 8.8.3 Constructor Modifiers
415 * @jls 8.9.2 Enum Body Declarations
416 */
417 @Override
418 public String toGenericString() {
419 return sharedToGenericString(Modifier.constructorModifiers(), false);
420 }
421
422 @Override
423 void specificToGenericStringHeader(StringBuilder sb) {
424 specificToStringHeader(sb);
425 }
426
427 /**
428 * Uses the constructor represented by this {@code Constructor} object to
429 * create and initialize a new instance of the constructor's
430 * declaring class, with the specified initialization parameters.
431 * Individual parameters are automatically unwrapped to match
432 * primitive formal parameters, and both primitive and reference
433 * parameters are subject to method invocation conversions as necessary.
434 *
435 * <p>If the number of formal parameters required by the underlying constructor
436 * is 0, the supplied {@code initargs} array may be of length 0 or null.
437 *
438 * <p>If the constructor's declaring class is an inner class in a
439 * non-static context, the first argument to the constructor needs
440 * to be the enclosing instance; see section 15.9.3 of
441 * <cite>The Java™ Language Specification</cite>.
442 *
443 * <p>If the required access and argument checks succeed and the
444 * instantiation will proceed, the constructor's declaring class
445 * is initialized if it has not already been initialized.
446 *
447 * <p>If the constructor completes normally, returns the newly
448 * created and initialized instance.
449 *
450 * @param initargs array of objects to be passed as arguments to
451 * the constructor call; values of primitive types are wrapped in
452 * a wrapper object of the appropriate type (e.g. a {@code float}
453 * in a {@link java.lang.Float Float})
454 *
455 * @return a new object created by calling the constructor
456 * this object represents
457 *
458 * @exception IllegalAccessException if this {@code Constructor} object
459 * is enforcing Java language access control and the underlying
460 * constructor is inaccessible.
461 * @exception IllegalArgumentException if the number of actual
462 * and formal parameters differ; if an unwrapping
463 * conversion for primitive arguments fails; or if,
464 * after possible unwrapping, a parameter value
465 * cannot be converted to the corresponding formal
466 * parameter type by a method invocation conversion; if
467 * this constructor pertains to an enum type.
468 * @exception InstantiationException if the class that declares the
469 * underlying constructor represents an abstract class.
470 * @exception InvocationTargetException if the underlying constructor
471 * throws an exception.
472 * @exception ExceptionInInitializerError if the initialization provoked
473 * by this method fails.
474 */
475 @CallerSensitive
476 @ForceInline // to ensure Reflection.getCallerClass optimization
477 public T newInstance(Object ... initargs)
478 throws InstantiationException, IllegalAccessException,
479 IllegalArgumentException, InvocationTargetException
480 {
481 Class<?> caller = override ? null : Reflection.getCallerClass();
482 return newInstanceWithCaller(initargs, !override, caller);
483 }
484
485 /* package-private */
486 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller)
487 throws InstantiationException, IllegalAccessException,
488 InvocationTargetException
489 {
490 if (checkAccess)
491 checkAccess(caller, clazz, clazz, modifiers);
492
493 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
494 throw new IllegalArgumentException("Cannot reflectively create enum objects");
495
496 ConstructorAccessor ca = constructorAccessor; // read volatile
497 if (ca == null) {
498 ca = acquireConstructorAccessor();
499 }
500 @SuppressWarnings("unchecked")
501 T inst = (T) ca.newInstance(args);
502 return inst;
503 }
504
505 /**
506 * {@inheritDoc}
507 * @since 1.5
508 */
509 @Override
510 public boolean isVarArgs() {
511 return super.isVarArgs();
512 }
513
514 /**
515 * {@inheritDoc}
516 * @jls 13.1 The Form of a Binary
517 * @since 1.5
518 */
519 @Override
520 public boolean isSynthetic() {
521 return super.isSynthetic();
522 }
523
524 // NOTE that there is no synchronization used here. It is correct
525 // (though not efficient) to generate more than one
526 // ConstructorAccessor for a given Constructor. However, avoiding
527 // synchronization will probably make the implementation more
528 // scalable.
529 private ConstructorAccessor acquireConstructorAccessor() {
530 // First check to see if one has been created yet, and take it
531 // if so.
532 ConstructorAccessor tmp = null;
533 if (root != null) tmp = root.getConstructorAccessor();
534 if (tmp != null) {
535 constructorAccessor = tmp;
536 } else {
537 // Otherwise fabricate one and propagate it up to the root
538 tmp = reflectionFactory.newConstructorAccessor(this);
539 setConstructorAccessor(tmp);
540 }
541
542 return tmp;
543 }
544
545 // Returns ConstructorAccessor for this Constructor object, not
546 // looking up the chain to the root
547 ConstructorAccessor getConstructorAccessor() {
548 return constructorAccessor;
549 }
550
551 // Sets the ConstructorAccessor for this Constructor object and
552 // (recursively) its root
553 void setConstructorAccessor(ConstructorAccessor accessor) {
554 constructorAccessor = accessor;
555 // Propagate up
556 if (root != null) {
557 root.setConstructorAccessor(accessor);
558 }
559 }
560
561 int getSlot() {
562 return slot;
563 }
564
565 String getSignature() {
566 return signature;
567 }
568
569 byte[] getRawAnnotations() {
570 return annotations;
571 }
572
573 byte[] getRawParameterAnnotations() {
574 return parameterAnnotations;
575 }
576
577
578 /**
579 * {@inheritDoc}
580 * @throws NullPointerException {@inheritDoc}
581 * @since 1.5
582 */
583 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
584 return super.getAnnotation(annotationClass);
585 }
586
587 /**
588 * {@inheritDoc}
589 * @since 1.5
590 */
591 public Annotation[] getDeclaredAnnotations() {
592 return super.getDeclaredAnnotations();
593 }
594
595 /**
596 * {@inheritDoc}
597 * @since 1.5
598 */
599 @Override
600 public Annotation[][] getParameterAnnotations() {
601 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
602 }
603
604 @Override
605 boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
606 Class<?> declaringClass = getDeclaringClass();
607 if (declaringClass.isEnum() ||
608 declaringClass.isAnonymousClass() ||
609 declaringClass.isLocalClass() )
610 return false; // Can't do reliable parameter counting
611 else {
612 if (declaringClass.isMemberClass() &&
613 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
614 resultLength + 1 == numParameters) {
615 return true;
616 } else {
617 throw new AnnotationFormatError(
618 "Parameter annotations don't match number of parameters");
619 }
620 }
621 }
622
623 /**
624 * {@inheritDoc}
625 * @since 1.8
626 */
627 @Override
628 public AnnotatedType getAnnotatedReturnType() {
629 return getAnnotatedReturnType0(getDeclaringClass());
630 }
631
632 /**
633 * {@inheritDoc}
634 * @since 1.8
635 */
636 @Override
637 public AnnotatedType getAnnotatedReceiverType() {
638 Class<?> thisDeclClass = getDeclaringClass();
639 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
640
641 if (enclosingClass == null) {
642 // A Constructor for a top-level class
643 return null;
644 }
645
646 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
647 if (outerDeclaringClass == null) {
648 // A constructor for a local or anonymous class
649 return null;
650 }
651
652 // Either static nested or inner class
653 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
654 // static nested
655 return null;
656 }
657
658 // A Constructor for an inner class
659 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
660 SharedSecrets.getJavaLangAccess().
661 getConstantPool(thisDeclClass),
662 this,
663 thisDeclClass,
664 enclosingClass,
665 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
666 }
667 }