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