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 if (clazz.isInlineClass()) {
184 throw new InaccessibleObjectException(
185 "Unable to make an inline 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, 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 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 * @exception IllegalAccessException if this {@code Constructor} object
463 * is enforcing Java language access control and the underlying
464 * constructor is inaccessible.
465 * @exception 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 type.
472 * @exception InstantiationException if the class that declares the
473 * underlying constructor represents an abstract class.
474 * @exception InvocationTargetException if the underlying constructor
475 * throws an exception.
476 * @exception 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 if (clazz.isInlineClass()) {
486 throw new IllegalAccessException(
487 "cannot create new instance of an inline class " + clazz.getName());
488 }
489 Class<?> caller = override ? null : Reflection.getCallerClass();
490 return newInstanceWithCaller(initargs, !override, caller);
491 }
492
493 /* package-private */
494 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller)
495 throws InstantiationException, IllegalAccessException,
496 InvocationTargetException
497 {
498 if (checkAccess)
499 checkAccess(caller, clazz, clazz, modifiers);
500
501 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
502 throw new IllegalArgumentException("Cannot reflectively create enum objects");
503
504 ConstructorAccessor ca = constructorAccessor; // read volatile
505 if (ca == null) {
506 ca = acquireConstructorAccessor();
507 }
508 @SuppressWarnings("unchecked")
509 T inst = (T) ca.newInstance(args);
510 return inst;
511 }
512
513 /**
514 * {@inheritDoc}
515 * @since 1.5
516 */
517 @Override
518 public boolean isVarArgs() {
519 return super.isVarArgs();
520 }
521
522 /**
523 * {@inheritDoc}
524 * @jls 13.1 The Form of a Binary
525 * @since 1.5
526 */
527 @Override
528 public boolean isSynthetic() {
529 return super.isSynthetic();
530 }
531
532 // NOTE that there is no synchronization used here. It is correct
533 // (though not efficient) to generate more than one
534 // ConstructorAccessor for a given Constructor. However, avoiding
535 // synchronization will probably make the implementation more
536 // scalable.
537 private ConstructorAccessor acquireConstructorAccessor() {
538 // First check to see if one has been created yet, and take it
539 // if so.
540 ConstructorAccessor tmp = null;
541 if (root != null) tmp = root.getConstructorAccessor();
542 if (tmp != null) {
543 constructorAccessor = tmp;
544 } else {
545 // Otherwise fabricate one and propagate it up to the root
546 tmp = reflectionFactory.newConstructorAccessor(this);
547 setConstructorAccessor(tmp);
548 }
549
550 return tmp;
551 }
552
553 // Returns ConstructorAccessor for this Constructor object, not
554 // looking up the chain to the root
555 ConstructorAccessor getConstructorAccessor() {
556 return constructorAccessor;
557 }
558
559 // Sets the ConstructorAccessor for this Constructor object and
560 // (recursively) its root
561 void setConstructorAccessor(ConstructorAccessor accessor) {
562 constructorAccessor = accessor;
563 // Propagate up
564 if (root != null) {
565 root.setConstructorAccessor(accessor);
566 }
567 }
568
569 int getSlot() {
570 return slot;
571 }
572
573 String getSignature() {
574 return signature;
575 }
576
577 byte[] getRawAnnotations() {
578 return annotations;
579 }
580
581 byte[] getRawParameterAnnotations() {
582 return parameterAnnotations;
583 }
584
585
586 /**
587 * {@inheritDoc}
588 * @throws NullPointerException {@inheritDoc}
589 * @since 1.5
590 */
591 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
592 return super.getAnnotation(annotationClass);
593 }
594
595 /**
596 * {@inheritDoc}
597 * @since 1.5
598 */
599 public Annotation[] getDeclaredAnnotations() {
600 return super.getDeclaredAnnotations();
601 }
602
603 /**
604 * {@inheritDoc}
605 * @since 1.5
606 */
607 @Override
608 public Annotation[][] getParameterAnnotations() {
609 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
610 }
611
612 @Override
613 boolean handleParameterNumberMismatch(int resultLength, int numParameters) {
614 Class<?> declaringClass = getDeclaringClass();
615 if (declaringClass.isEnum() ||
616 declaringClass.isAnonymousClass() ||
617 declaringClass.isLocalClass() )
618 return false; // Can't do reliable parameter counting
619 else {
620 if (declaringClass.isMemberClass() &&
621 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
622 resultLength + 1 == numParameters) {
623 return true;
624 } else {
625 throw new AnnotationFormatError(
626 "Parameter annotations don't match number of parameters");
627 }
628 }
629 }
630
631 /**
632 * {@inheritDoc}
633 * @since 1.8
634 */
635 @Override
636 public AnnotatedType getAnnotatedReturnType() {
637 return getAnnotatedReturnType0(getDeclaringClass());
638 }
639
640 /**
641 * {@inheritDoc}
642 * @since 1.8
643 */
644 @Override
645 public AnnotatedType getAnnotatedReceiverType() {
646 Class<?> thisDeclClass = getDeclaringClass();
647 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
648
649 if (enclosingClass == null) {
650 // A Constructor for a top-level class
651 return null;
652 }
653
654 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
655 if (outerDeclaringClass == null) {
656 // A constructor for a local or anonymous class
657 return null;
658 }
659
660 // Either static nested or inner class
661 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
662 // static nested
663 return null;
664 }
665
666 // A Constructor for an inner class
667 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
668 SharedSecrets.getJavaLangAccess().
669 getConstantPool(thisDeclClass),
670 this,
671 thisDeclClass,
672 enclosingClass,
673 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
674 }
675 }