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