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