1 /*
2 * Copyright (c) 1996, 2013, 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
42 /**
43 * {@code Constructor} provides information about, and access to, a single
44 * constructor for a class.
45 *
46 * <p>{@code Constructor} permits widening conversions to occur when matching the
47 * actual parameters to newInstance() with the underlying
48 * constructor's formal parameters, but throws an
49 * {@code IllegalArgumentException} if a narrowing conversion would occur.
50 *
51 * @param <T> the class in which the constructor is declared
52 *
53 * @see Member
54 * @see java.lang.Class
55 * @see java.lang.Class#getConstructors()
56 * @see java.lang.Class#getConstructor(Class[])
57 * @see java.lang.Class#getDeclaredConstructors()
58 *
59 * @author Kenneth Russell
60 * @author Nakul Saraiya
61 */
62 public final class Constructor<T> extends Executable {
63 private Class<T> clazz;
64 private int slot;
65 private Class<?>[] parameterTypes;
66 private Class<?>[] exceptionTypes;
67 private int modifiers;
68 // Generics and annotations support
69 private transient String signature;
70 // generic info repository; lazily initialized
71 private transient ConstructorRepository genericInfo;
72 private byte[] annotations;
73 private byte[] parameterAnnotations;
74
75 // Generics infrastructure
76 // Accessor for factory
77 private GenericsFactory getFactory() {
78 // create scope and factory
79 return CoreReflectionFactory.make(this, ConstructorScope.make(this));
80 }
81
82 // Accessor for generic info repository
83 @Override
84 ConstructorRepository getGenericInfo() {
85 // lazily initialize repository if necessary
86 if (genericInfo == null) {
87 // create and cache generic info repository
88 genericInfo =
89 ConstructorRepository.make(getSignature(),
90 getFactory());
91 }
92 return genericInfo; //return cached repository
93 }
94
95 private volatile ConstructorAccessor constructorAccessor;
96 // For sharing of ConstructorAccessors. This branching structure
97 // is currently only two levels deep (i.e., one root Constructor
98 // and potentially many Constructor objects pointing to it.)
99 //
100 // If this branching structure would ever contain cycles, deadlocks can
101 // occur in annotation code.
102 private Constructor<T> root;
103
104 /**
105 * Used by Excecutable for annotation sharing.
106 */
107 @Override
108 Executable getRoot() {
109 return root;
110 }
111
112 /**
113 * Package-private constructor used by ReflectAccess to enable
114 * instantiation of these objects in Java code from the java.lang
115 * package via sun.reflect.LangReflectAccess.
116 */
117 Constructor(Class<T> declaringClass,
118 Class<?>[] parameterTypes,
119 Class<?>[] checkedExceptions,
120 int modifiers,
121 int slot,
122 String signature,
123 byte[] annotations,
124 byte[] parameterAnnotations) {
125 this.clazz = declaringClass;
126 this.parameterTypes = parameterTypes;
127 this.exceptionTypes = checkedExceptions;
128 this.modifiers = modifiers;
129 this.slot = slot;
130 this.signature = signature;
131 this.annotations = annotations;
132 this.parameterAnnotations = parameterAnnotations;
133 }
134
135 /**
136 * Package-private routine (exposed to java.lang.Class via
137 * ReflectAccess) which returns a copy of this Constructor. The copy's
138 * "root" field points to this Constructor.
139 */
140 Constructor<T> copy() {
141 // This routine enables sharing of ConstructorAccessor objects
142 // among Constructor objects which refer to the same underlying
143 // method in the VM. (All of this contortion is only necessary
144 // because of the "accessibility" bit in AccessibleObject,
145 // which implicitly requires that new java.lang.reflect
146 // objects be fabricated for each reflective call on Class
147 // objects.)
148 if (this.root != null)
149 throw new IllegalArgumentException("Can not copy a non-root Constructor");
150
151 Constructor<T> res = new Constructor<>(clazz,
152 parameterTypes,
153 exceptionTypes, modifiers, slot,
154 signature,
155 annotations,
156 parameterAnnotations);
157 res.root = this;
158 // Might as well eagerly propagate this if already present
159 res.constructorAccessor = constructorAccessor;
160 return res;
161 }
162
163 /**
164 * {@inheritDoc}
165 *
166 * <p> A {@code SecurityException} is also thrown if this object is a
167 * {@code Constructor} object for the class {@code Class} and {@code flag}
168 * is true. </p>
169 *
170 * @param flag {@inheritDoc}
171 */
172 @Override
173 @CallerSensitive
174 public void setAccessible(boolean flag) {
175 AccessibleObject.checkPermission();
176 if (flag) {
177 checkCanSetAccessible(Reflection.getCallerClass());
178 }
179 setAccessible0(flag);
180 }
181
182 @Override
183 void checkCanSetAccessible(Class<?> caller) {
184 checkCanSetAccessible(caller, clazz);
185 if (clazz == Class.class) {
186 // can we change this to InaccessibleObjectException?
187 throw new SecurityException("Cannot make a java.lang.Class"
188 + " constructor accessible");
189 }
190 }
191
192 @Override
193 boolean hasGenericInformation() {
194 return (getSignature() != null);
195 }
196
197 @Override
198 byte[] getAnnotationBytes() {
199 return annotations;
200 }
201
202 /**
203 * Returns the {@code Class} object representing the class that
204 * declares the constructor represented by this object.
205 */
206 @Override
207 public Class<T> getDeclaringClass() {
208 return clazz;
209 }
210
211 /**
212 * Returns the name of this constructor, as a string. This is
213 * the binary name of the constructor's declaring class.
214 */
215 @Override
216 public String getName() {
217 return getDeclaringClass().getName();
218 }
219
220 /**
221 * {@inheritDoc}
222 */
223 @Override
224 public int getModifiers() {
225 return modifiers;
226 }
227
228 /**
229 * {@inheritDoc}
230 * @throws GenericSignatureFormatError {@inheritDoc}
231 * @since 1.5
232 */
233 @Override
234 @SuppressWarnings({"rawtypes", "unchecked"})
235 public TypeVariable<Constructor<T>>[] getTypeParameters() {
236 if (getSignature() != null) {
237 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
238 } else
239 return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
240 }
241
242
243 @Override
244 Class<?>[] getSharedParameterTypes() {
245 return parameterTypes;
246 }
247
248 /**
249 * {@inheritDoc}
250 */
251 @Override
252 public Class<?>[] getParameterTypes() {
253 return parameterTypes.clone();
254 }
255
256 /**
257 * {@inheritDoc}
258 * @since 1.8
259 */
260 public int getParameterCount() { return parameterTypes.length; }
261
262 /**
263 * {@inheritDoc}
264 * @throws GenericSignatureFormatError {@inheritDoc}
265 * @throws TypeNotPresentException {@inheritDoc}
266 * @throws MalformedParameterizedTypeException {@inheritDoc}
267 * @since 1.5
268 */
269 @Override
270 public Type[] getGenericParameterTypes() {
271 return super.getGenericParameterTypes();
272 }
273
274 /**
275 * {@inheritDoc}
276 */
277 @Override
278 public Class<?>[] getExceptionTypes() {
279 return exceptionTypes.clone();
280 }
281
282
283 /**
284 * {@inheritDoc}
285 * @throws GenericSignatureFormatError {@inheritDoc}
286 * @throws TypeNotPresentException {@inheritDoc}
287 * @throws MalformedParameterizedTypeException {@inheritDoc}
288 * @since 1.5
289 */
290 @Override
291 public Type[] getGenericExceptionTypes() {
292 return super.getGenericExceptionTypes();
293 }
294
295 /**
296 * Compares this {@code Constructor} against the specified object.
297 * Returns true if the objects are the same. Two {@code Constructor} objects are
298 * the same if they were declared by the same class and have the
299 * same formal parameter types.
300 */
301 public boolean equals(Object obj) {
302 if (obj != null && obj instanceof Constructor) {
303 Constructor<?> other = (Constructor<?>)obj;
304 if (getDeclaringClass() == other.getDeclaringClass()) {
305 return equalParamTypes(parameterTypes, other.parameterTypes);
306 }
307 }
308 return false;
309 }
310
311 /**
312 * Returns a hashcode for this {@code Constructor}. The hashcode is
313 * the same as the hashcode for the underlying constructor's
314 * declaring class name.
315 */
316 public int hashCode() {
317 return getDeclaringClass().getName().hashCode();
318 }
319
320 /**
321 * Returns a string describing this {@code Constructor}. The string is
322 * formatted as the constructor access modifiers, if any,
323 * followed by the fully-qualified name of the declaring class,
324 * followed by a parenthesized, comma-separated list of the
325 * constructor's formal parameter types. For example:
326 * <pre>{@code
327 * public java.util.Hashtable(int,float)
328 * }</pre>
329 *
330 * <p>If the constructor is declared to throw exceptions, the
331 * parameter list is followed by a space, followed by the word
332 * "{@code throws}" followed by a comma-separated list of the
333 * thrown exception types.
334 *
335 * <p>The only possible modifiers for constructors are the access
336 * modifiers {@code public}, {@code protected} or
337 * {@code private}. Only one of these may appear, or none if the
338 * constructor has default (package) access.
339 *
340 * @return a string describing this {@code Constructor}
341 * @jls 8.8.3 Constructor Modifiers
342 * @jls 8.9.2 Enum Body Declarations
343 */
344 public String toString() {
345 return sharedToString(Modifier.constructorModifiers(),
346 false,
347 parameterTypes,
348 exceptionTypes);
349 }
350
351 @Override
352 void specificToStringHeader(StringBuilder sb) {
353 sb.append(getDeclaringClass().getTypeName());
354 }
355
356 /**
357 * Returns a string describing this {@code Constructor},
358 * including type parameters. The string is formatted as the
359 * constructor access modifiers, if any, followed by an
360 * angle-bracketed comma separated list of the constructor's type
361 * parameters, if any, followed by the fully-qualified name of the
362 * declaring class, followed by a parenthesized, comma-separated
363 * list of the constructor's generic formal parameter types.
364 *
365 * If this constructor was declared to take a variable number of
366 * arguments, instead of denoting the last parameter as
367 * "<code><i>Type</i>[]</code>", it is denoted as
368 * "<code><i>Type</i>...</code>".
369 *
370 * A space is used to separate access modifiers from one another
371 * and from the type parameters or class name. If there are no
372 * type parameters, the type parameter list is elided; if the type
373 * parameter list is present, a space separates the list from the
374 * class name. If the constructor is declared to throw
375 * exceptions, the parameter list is followed by a space, followed
376 * by the word "{@code throws}" followed by a
377 * comma-separated list of the generic thrown exception types.
378 *
379 * <p>The only possible modifiers for constructors are the access
380 * modifiers {@code public}, {@code protected} or
381 * {@code private}. Only one of these may appear, or none if the
382 * constructor has default (package) access.
383 *
384 * @return a string describing this {@code Constructor},
385 * include type parameters
386 *
387 * @since 1.5
388 * @jls 8.8.3 Constructor Modifiers
389 * @jls 8.9.2 Enum Body Declarations
390 */
391 @Override
392 public String toGenericString() {
393 return sharedToGenericString(Modifier.constructorModifiers(), false);
394 }
395
396 @Override
397 void specificToGenericStringHeader(StringBuilder sb) {
398 specificToStringHeader(sb);
399 }
400
401 /**
402 * Uses the constructor represented by this {@code Constructor} object to
403 * create and initialize a new instance of the constructor's
404 * declaring class, with the specified initialization parameters.
405 * Individual parameters are automatically unwrapped to match
406 * primitive formal parameters, and both primitive and reference
407 * parameters are subject to method invocation conversions as necessary.
408 *
409 * <p>If the number of formal parameters required by the underlying constructor
410 * is 0, the supplied {@code initargs} array may be of length 0 or null.
411 *
412 * <p>If the constructor's declaring class is an inner class in a
413 * non-static context, the first argument to the constructor needs
414 * to be the enclosing instance; see section 15.9.3 of
415 * <cite>The Java™ Language Specification</cite>.
416 *
417 * <p>If the required access and argument checks succeed and the
418 * instantiation will proceed, the constructor's declaring class
419 * is initialized if it has not already been initialized.
420 *
421 * <p>If the constructor completes normally, returns the newly
422 * created and initialized instance.
423 *
424 * @param initargs array of objects to be passed as arguments to
425 * the constructor call; values of primitive types are wrapped in
426 * a wrapper object of the appropriate type (e.g. a {@code float}
427 * in a {@link java.lang.Float Float})
428 *
429 * @return a new object created by calling the constructor
430 * this object represents
431 *
432 * @exception IllegalAccessException if this {@code Constructor} object
433 * is enforcing Java language access control and the underlying
434 * constructor is inaccessible.
435 * @exception IllegalArgumentException if the number of actual
436 * and formal parameters differ; if an unwrapping
437 * conversion for primitive arguments fails; or if,
438 * after possible unwrapping, a parameter value
439 * cannot be converted to the corresponding formal
440 * parameter type by a method invocation conversion; if
441 * this constructor pertains to an enum type.
442 * @exception InstantiationException if the class that declares the
443 * underlying constructor represents an abstract class.
444 * @exception InvocationTargetException if the underlying constructor
445 * throws an exception.
446 * @exception ExceptionInInitializerError if the initialization provoked
447 * by this method fails.
448 */
449 @CallerSensitive
450 @ForceInline // to ensure Reflection.getCallerClass optimization
451 public T newInstance(Object ... initargs)
452 throws InstantiationException, IllegalAccessException,
453 IllegalArgumentException, InvocationTargetException
454 {
455 if (!override) {
456 Class<?> caller = Reflection.getCallerClass();
457 checkAccess(caller, clazz, clazz, modifiers);
458 }
459 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
460 throw new IllegalArgumentException("Cannot reflectively create enum objects");
461 ConstructorAccessor ca = constructorAccessor; // read volatile
462 if (ca == null) {
463 ca = acquireConstructorAccessor();
464 }
465 @SuppressWarnings("unchecked")
466 T inst = (T) ca.newInstance(initargs);
467 return inst;
468 }
469
470 /**
471 * {@inheritDoc}
472 * @since 1.5
473 */
474 @Override
475 public boolean isVarArgs() {
476 return super.isVarArgs();
477 }
478
479 /**
480 * {@inheritDoc}
481 * @jls 13.1 The Form of a Binary
482 * @since 1.5
483 */
484 @Override
485 public boolean isSynthetic() {
486 return super.isSynthetic();
487 }
488
489 // NOTE that there is no synchronization used here. It is correct
490 // (though not efficient) to generate more than one
491 // ConstructorAccessor for a given Constructor. However, avoiding
492 // synchronization will probably make the implementation more
493 // scalable.
494 private ConstructorAccessor acquireConstructorAccessor() {
495 // First check to see if one has been created yet, and take it
496 // if so.
497 ConstructorAccessor tmp = null;
498 if (root != null) tmp = root.getConstructorAccessor();
499 if (tmp != null) {
500 constructorAccessor = tmp;
501 } else {
502 // Otherwise fabricate one and propagate it up to the root
503 tmp = reflectionFactory.newConstructorAccessor(this);
504 setConstructorAccessor(tmp);
505 }
506
507 return tmp;
508 }
509
510 // Returns ConstructorAccessor for this Constructor object, not
511 // looking up the chain to the root
512 ConstructorAccessor getConstructorAccessor() {
513 return constructorAccessor;
514 }
515
516 // Sets the ConstructorAccessor for this Constructor object and
517 // (recursively) its root
518 void setConstructorAccessor(ConstructorAccessor accessor) {
519 constructorAccessor = accessor;
520 // Propagate up
521 if (root != null) {
522 root.setConstructorAccessor(accessor);
523 }
524 }
525
526 int getSlot() {
527 return slot;
528 }
529
530 String getSignature() {
531 return signature;
532 }
533
534 byte[] getRawAnnotations() {
535 return annotations;
536 }
537
538 byte[] getRawParameterAnnotations() {
539 return parameterAnnotations;
540 }
541
542
543 /**
544 * {@inheritDoc}
545 * @throws NullPointerException {@inheritDoc}
546 * @since 1.5
547 */
548 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
549 return super.getAnnotation(annotationClass);
550 }
551
552 /**
553 * {@inheritDoc}
554 * @since 1.5
555 */
556 public Annotation[] getDeclaredAnnotations() {
557 return super.getDeclaredAnnotations();
558 }
559
560 /**
561 * {@inheritDoc}
562 * @since 1.5
563 */
564 @Override
565 public Annotation[][] getParameterAnnotations() {
566 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
567 }
568
569 @Override
570 void handleParameterNumberMismatch(int resultLength, int numParameters) {
571 Class<?> declaringClass = getDeclaringClass();
572 if (declaringClass.isEnum() ||
573 declaringClass.isAnonymousClass() ||
574 declaringClass.isLocalClass() )
575 return ; // Can't do reliable parameter counting
576 else {
577 if (!declaringClass.isMemberClass() || // top-level
578 // Check for the enclosing instance parameter for
579 // non-static member classes
580 (declaringClass.isMemberClass() &&
581 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
582 resultLength + 1 != numParameters) ) {
583 throw new AnnotationFormatError(
584 "Parameter annotations don't match number of parameters");
585 }
586 }
587 }
588
589 /**
590 * {@inheritDoc}
591 * @since 1.8
592 */
593 @Override
594 public AnnotatedType getAnnotatedReturnType() {
595 return getAnnotatedReturnType0(getDeclaringClass());
596 }
597
598 /**
599 * {@inheritDoc}
600 * @since 1.8
601 */
602 @Override
603 public AnnotatedType getAnnotatedReceiverType() {
604 Class<?> thisDeclClass = getDeclaringClass();
605 Class<?> enclosingClass = thisDeclClass.getEnclosingClass();
606
607 if (enclosingClass == null) {
608 // A Constructor for a top-level class
609 return null;
610 }
611
612 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass();
613 if (outerDeclaringClass == null) {
614 // A constructor for a local or anonymous class
615 return null;
616 }
617
618 // Either static nested or inner class
619 if (Modifier.isStatic(thisDeclClass.getModifiers())) {
620 // static nested
621 return null;
622 }
623
624 // A Constructor for an inner class
625 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(),
626 SharedSecrets.getJavaLangAccess().
627 getConstantPool(thisDeclClass),
628 this,
629 thisDeclClass,
630 enclosingClass,
631 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER);
632 }
633 }