1 /*
2 * Copyright (c) 1996, 2017, 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.misc.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 if (clazz.isValue()) {
184 throw new InaccessibleObjectException(
185 "Unable to make a value class constructor \"" + this + "\" accessible");
186 }
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 */
233 @Override
234 public int getModifiers() {
235 return modifiers;
236 }
237
238 /**
239 * {@inheritDoc}
240 * @throws GenericSignatureFormatError {@inheritDoc}
241 * @since 1.5
242 */
243 @Override
244 @SuppressWarnings({"rawtypes", "unchecked"})
245 public TypeVariable<Constructor<T>>[] getTypeParameters() {
246 if (getSignature() != null) {
247 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
248 } else
249 return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
250 }
251
252
253 @Override
254 Class<?>[] getSharedParameterTypes() {
255 return parameterTypes;
256 }
257
258 @Override
259 Class<?>[] getSharedExceptionTypes() {
260 return exceptionTypes;
261 }
262
263 /**
264 * {@inheritDoc}
265 */
266 @Override
267 public Class<?>[] getParameterTypes() {
268 return parameterTypes.clone();
269 }
270
271 /**
272 * {@inheritDoc}
273 * @since 1.8
274 */
275 public int getParameterCount() { return parameterTypes.length; }
276
277 /**
278 * {@inheritDoc}
279 * @throws GenericSignatureFormatError {@inheritDoc}
280 * @throws TypeNotPresentException {@inheritDoc}
281 * @throws MalformedParameterizedTypeException {@inheritDoc}
282 * @since 1.5
283 */
284 @Override
285 public Type[] getGenericParameterTypes() {
286 return super.getGenericParameterTypes();
287 }
288
289 /**
290 * {@inheritDoc}
291 */
292 @Override
293 public Class<?>[] getExceptionTypes() {
294 return exceptionTypes.clone();
295 }
296
297
298 /**
299 * {@inheritDoc}
300 * @throws GenericSignatureFormatError {@inheritDoc}
301 * @throws TypeNotPresentException {@inheritDoc}
302 * @throws MalformedParameterizedTypeException {@inheritDoc}
303 * @since 1.5
304 */
305 @Override
306 public Type[] getGenericExceptionTypes() {
307 return super.getGenericExceptionTypes();
308 }
309
310 /**
311 * Compares this {@code Constructor} against the specified object.
312 * Returns true if the objects are the same. Two {@code Constructor} objects are
313 * the same if they were declared by the same class and have the
314 * same formal parameter types.
315 */
316 public boolean equals(Object obj) {
317 if (obj != null && obj instanceof Constructor) {
318 Constructor<?> other = (Constructor<?>)obj;
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.Hashtable(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(getDeclaringClass().getTypeName());
369 }
370
371 @Override
372 String toShortString() {
373 StringBuilder sb = new StringBuilder("constructor ");
374 sb.append(getDeclaringClass().getTypeName());
375 sb.append('(');
376 StringJoiner sj = new StringJoiner(",");
377 for (Class<?> parameterType : getParameterTypes()) {
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, followed by the fully-qualified name of the
391 * declaring class, followed by a parenthesized, comma-separated
392 * list of the constructor's generic formal parameter types.
393 *
394 * If this constructor was declared to take a variable number of
395 * arguments, instead of denoting the last parameter as
396 * "<code><i>Type</i>[]</code>", it is denoted as
397 * "<code><i>Type</i>...</code>".
398 *
399 * A space is used to separate access modifiers from one another
400 * and from the type parameters or class name. If there are no
401 * type parameters, the type parameter list is elided; if the type
402 * parameter list is present, a space separates the list from the
403 * class name. If the constructor is declared to throw
404 * exceptions, the parameter list is followed by a space, followed
405 * by the word "{@code throws}" followed by a
406 * comma-separated list of the generic thrown exception types.
407 *
408 * <p>The only possible modifiers for constructors are the access
409 * modifiers {@code public}, {@code protected} or
410 * {@code private}. Only one of these may appear, or none if the
411 * constructor has default (package) access.
412 *
413 * @return a string describing this {@code Constructor},
414 * include type parameters
415 *
416 * @since 1.5
417 * @jls 8.8.3 Constructor Modifiers
418 * @jls 8.9.2 Enum Body Declarations
419 */
420 @Override
421 public String toGenericString() {
422 return sharedToGenericString(Modifier.constructorModifiers(), false);
423 }
424
425 @Override
426 void specificToGenericStringHeader(StringBuilder sb) {
427 specificToStringHeader(sb);
428 }
429
430 /**
431 * Uses the constructor represented by this {@code Constructor} object to
432 * create and initialize a new instance of the constructor's
433 * declaring class, with the specified initialization parameters.
434 * Individual parameters are automatically unwrapped to match
435 * primitive formal parameters, and both primitive and reference
436 * parameters are subject to method invocation conversions as necessary.
437 *
438 * <p>If the number of formal parameters required by the underlying constructor
439 * is 0, the supplied {@code initargs} array may be of length 0 or null.
440 *
441 * <p>If the constructor's declaring class is an inner class in a
442 * non-static context, the first argument to the constructor needs
443 * to be the enclosing instance; see section 15.9.3 of
444 * <cite>The Java™ Language Specification</cite>.
445 *
446 * <p>If the required access and argument checks succeed and the
447 * instantiation will proceed, the constructor's declaring class
448 * is initialized if it has not already been initialized.
449 *
450 * <p>If the constructor completes normally, returns the newly
451 * created and initialized instance.
452 *
453 * @param initargs array of objects to be passed as arguments to
454 * the constructor call; values of primitive types are wrapped in
455 * a wrapper object of the appropriate type (e.g. a {@code float}
456 * in a {@link java.lang.Float Float})
457 *
458 * @return a new object created by calling the constructor
459 * this object represents
460 *
461 * @exception IllegalAccessException if this {@code Constructor} object
462 * is enforcing Java language access control and the underlying
463 * constructor is inaccessible.
464 * @exception IllegalArgumentException if the number of actual
465 * and formal parameters differ; if an unwrapping
466 * conversion for primitive arguments fails; or if,
467 * after possible unwrapping, a parameter value
468 * cannot be converted to the corresponding formal
469 * parameter type by a method invocation conversion; if
470 * this constructor pertains to an enum type.
471 * @exception InstantiationException if the class that declares the
472 * underlying constructor represents an abstract class.
473 * @exception InvocationTargetException if the underlying constructor
474 * throws an exception.
475 * @exception ExceptionInInitializerError if the initialization provoked
476 * by this method fails.
477 */
478 @CallerSensitive
479 @ForceInline // to ensure Reflection.getCallerClass optimization
480 public T newInstance(Object ... initargs)
481 throws InstantiationException, IllegalAccessException,
482 IllegalArgumentException, InvocationTargetException
483 {
484 if (clazz.isValue()) {
485 throw new IllegalAccessException(
486 "cannot create new instance of value class " + clazz.getName());
487 }
488
489 if (!override) {
490 Class<?> caller = Reflection.getCallerClass();
491 checkAccess(caller, clazz, clazz, modifiers);
492 }
493 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
494 throw new IllegalArgumentException("Cannot reflectively create enum objects");
495 ConstructorAccessor ca = constructorAccessor; // read volatile
496 if (ca == null) {
497 ca = acquireConstructorAccessor();
498 }
499 @SuppressWarnings("unchecked")
500 T inst = (T) ca.newInstance(initargs);
501 return inst;
502 }
503
504 /**
505 * {@inheritDoc}
506 * @since 1.5
507 */
508 @Override
509 public boolean isVarArgs() {
510 return super.isVarArgs();
511 }
512
513 /**
514 * {@inheritDoc}
515 * @jls 13.1 The Form of a Binary
516 * @since 1.5
517 */
518 @Override
519 public boolean isSynthetic() {
520 return super.isSynthetic();
521 }
522
523 // NOTE that there is no synchronization used here. It is correct
524 // (though not efficient) to generate more than one
525 // ConstructorAccessor for a given Constructor. However, avoiding
526 // synchronization will probably make the implementation more
527 // scalable.
528 private ConstructorAccessor acquireConstructorAccessor() {
529 // First check to see if one has been created yet, and take it
530 // if so.
531 ConstructorAccessor tmp = null;
532 if (root != null) tmp = root.getConstructorAccessor();
533 if (tmp != null) {
534 constructorAccessor = tmp;
535 } else {
536 // Otherwise fabricate one and propagate it up to the root
537 tmp = reflectionFactory.newConstructorAccessor(this);
538 setConstructorAccessor(tmp);
539 }
540
541 return tmp;
542 }
543
544 // Returns ConstructorAccessor for this Constructor object, not
545 // looking up the chain to the root
546 ConstructorAccessor getConstructorAccessor() {
547 return constructorAccessor;
548 }
549
550 // Sets the ConstructorAccessor for this Constructor object and
551 // (recursively) its root
552 void setConstructorAccessor(ConstructorAccessor accessor) {
553 constructorAccessor = accessor;
554 // Propagate up
555 if (root != null) {
556 root.setConstructorAccessor(accessor);
557 }
558 }
559
560 int getSlot() {
561 return slot;
562 }
563
564 String getSignature() {
565 return signature;
566 }
567
568 byte[] getRawAnnotations() {
569 return annotations;
570 }
571
572 byte[] getRawParameterAnnotations() {
573 return parameterAnnotations;
574 }
575
576
577 /**
578 * {@inheritDoc}
579 * @throws NullPointerException {@inheritDoc}
580 * @since 1.5
581 */
582 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
583 return super.getAnnotation(annotationClass);
584 }
585
586 /**
587 * {@inheritDoc}
588 * @since 1.5
589 */
590 public Annotation[] getDeclaredAnnotations() {
591 return super.getDeclaredAnnotations();
592 }
593
594 /**
595 * {@inheritDoc}
596 * @since 1.5
597 */
598 @Override
599 public Annotation[][] getParameterAnnotations() {
600 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
601 }
602
603 @Override
604 boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
605 Class<?> declaringClass = getDeclaringClass();
606 if (declaringClass.isEnum() ||
607 declaringClass.isAnonymousClass() ||
608 declaringClass.isLocalClass() )
609 return false; // Can't do reliable parameter counting
610 else {
611 if (declaringClass.isMemberClass() &&
612 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
613 resultLength + 1 == numParameters) {
614 return true;
615 } else {
616 throw new AnnotationFormatError(
617 "Parameter annotations don't match number of parameters");
618 }
619 }
620 }
621
622 /**
623 * {@inheritDoc}
624 * @since 1.8
625 */
626 @Override
627 public AnnotatedType getAnnotatedReturnType() {
628 return getAnnotatedReturnType0(getDeclaringClass());
629 }
630
631 /**
632 * {@inheritDoc}
633 * @since 1.8
634 */
635 @Override
636 public AnnotatedType getAnnotatedReceiverType() {
637 Class<?> thisDeclClass = getDeclaringClass();
638 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
639
640 if (enclosingClass == null) {
641 // A Constructor for a top-level class
642 return null;
643 }
644
645 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
646 if (outerDeclaringClass == null) {
647 // A constructor for a local or anonymous class
648 return null;
649 }
650
651 // Either static nested or inner class
652 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
653 // static nested
654 return null;
655 }
656
657 // A Constructor for an inner class
658 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
659 SharedSecrets.getJavaLangAccess().
660 getConstantPool(thisDeclClass),
661 this,
662 thisDeclClass,
663 enclosingClass,
664 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
665 }
666 }