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