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.ConstructorAccessor;
29 import sun.reflect.Reflection;
30 import sun.reflect.generics.repository.ConstructorRepository;
31 import sun.reflect.generics.factory.CoreReflectionFactory;
32 import sun.reflect.generics.factory.GenericsFactory;
33 import sun.reflect.generics.scope.ConstructorScope;
34 import java.lang.annotation.Annotation;
35 import java.lang.annotation.AnnotationFormatError;
36
37 /**
38 * {@code Constructor} provides information about, and access to, a single
39 * constructor for a class.
40 *
41 * <p>{@code Constructor} permits widening conversions to occur when matching the
42 * actual parameters to newInstance() with the underlying
43 * constructor's formal parameters, but throws an
44 * {@code IllegalArgumentException} if a narrowing conversion would occur.
45 *
46 * @param <T> the class in which the constructor is declared
47 *
48 * @see Member
49 * @see java.lang.Class
50 * @see java.lang.Class#getConstructors()
51 * @see java.lang.Class#getConstructor(Class[])
52 * @see java.lang.Class#getDeclaredConstructors()
53 *
54 * @author Kenneth Russell
55 * @author Nakul Saraiya
56 */
57 public final class Constructor<T> extends Executable {
58 private Class<T> clazz;
59 private int slot;
60 private Class<?>[] parameterTypes;
61 private Class<?>[] exceptionTypes;
62 private int modifiers;
63 // Generics and annotations support
64 private transient String signature;
65 // generic info repository; lazily initialized
66 private transient ConstructorRepository genericInfo;
67 private byte[] annotations;
68 private byte[] parameterAnnotations;
69 // This is set by the vm at Constructor creation
70 private byte[] typeAnnotations;
71
72 // Generics infrastructure
73 // Accessor for factory
74 private GenericsFactory getFactory() {
75 // create scope and factory
76 return CoreReflectionFactory.make(this, ConstructorScope.make(this));
77 }
78
79 // Accessor for generic info repository
80 @Override
81 ConstructorRepository getGenericInfo() {
82 // lazily initialize repository if necessary
83 if (genericInfo == null) {
84 // create and cache generic info repository
85 genericInfo =
86 ConstructorRepository.make(getSignature(),
87 getFactory());
88 }
89 return genericInfo; //return cached repository
90 }
91
92 private volatile ConstructorAccessor constructorAccessor;
93 // For sharing of ConstructorAccessors. This branching structure
94 // is currently only two levels deep (i.e., one root Constructor
95 // and potentially many Constructor objects pointing to it.)
96 private Constructor<T> root;
97
98 /**
99 * Package-private constructor used by ReflectAccess to enable
100 * instantiation of these objects in Java code from the java.lang
101 * package via sun.reflect.LangReflectAccess.
102 */
103 Constructor(Class<T> declaringClass,
104 Class<?>[] parameterTypes,
105 Class<?>[] checkedExceptions,
106 int modifiers,
107 int slot,
108 String signature,
109 byte[] annotations,
110 byte[] parameterAnnotations) {
111 this.clazz = declaringClass;
112 this.parameterTypes = parameterTypes;
113 this.exceptionTypes = checkedExceptions;
114 this.modifiers = modifiers;
115 this.slot = slot;
116 this.signature = signature;
117 this.annotations = annotations;
118 this.parameterAnnotations = parameterAnnotations;
119 }
120
121 /**
122 * Package-private routine (exposed to java.lang.Class via
123 * ReflectAccess) which returns a copy of this Constructor. The copy's
124 * "root" field points to this Constructor.
125 */
126 Constructor<T> copy() {
127 // This routine enables sharing of ConstructorAccessor objects
128 // among Constructor objects which refer to the same underlying
129 // method in the VM. (All of this contortion is only necessary
130 // because of the "accessibility" bit in AccessibleObject,
131 // which implicitly requires that new java.lang.reflect
132 // objects be fabricated for each reflective call on Class
133 // objects.)
134 Constructor<T> res = new Constructor<>(clazz,
135 parameterTypes,
136 exceptionTypes, modifiers, slot,
137 signature,
138 annotations,
139 parameterAnnotations);
140 res.root = this;
141 // Might as well eagerly propagate this if already present
142 res.constructorAccessor = constructorAccessor;
143
144 res.typeAnnotations = typeAnnotations;
145 return res;
146 }
147
148 @Override
149 boolean hasGenericInformation() {
150 return (getSignature() != null);
151 }
152
153 @Override
154 byte[] getAnnotationBytes() {
155 return annotations;
156 }
157 @Override
158 byte[] getTypeAnnotationBytes() {
159 return typeAnnotations;
160 }
161
162 /**
163 * {@inheritDoc}
164 */
165 @Override
166 public Class<T> getDeclaringClass() {
167 return clazz;
168 }
169
170 /**
171 * Returns the name of this constructor, as a string. This is
172 * the binary name of the constructor's declaring class.
173 */
174 @Override
175 public String getName() {
176 return getDeclaringClass().getName();
177 }
178
179 /**
180 * {@inheritDoc}
181 */
182 @Override
183 public int getModifiers() {
184 return modifiers;
185 }
186
187 /**
188 * {@inheritDoc}
189 * @throws GenericSignatureFormatError {@inheritDoc}
190 * @since 1.5
191 */
192 @Override
193 @SuppressWarnings({"rawtypes", "unchecked"})
194 public TypeVariable<Constructor<T>>[] getTypeParameters() {
195 if (getSignature() != null) {
196 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters();
197 } else
198 return (TypeVariable<Constructor<T>>[])new TypeVariable[0];
199 }
200
201
202 /**
203 * {@inheritDoc}
204 */
205 @Override
206 public Class<?>[] getParameterTypes() {
207 return parameterTypes.clone();
208 }
209
210 /**
211 * {@inheritDoc}
212 */
213 public int getParameterCount() { return parameterTypes.length; }
214
215 /**
216 * {@inheritDoc}
217 * @throws GenericSignatureFormatError {@inheritDoc}
218 * @throws TypeNotPresentException {@inheritDoc}
219 * @throws MalformedParameterizedTypeException {@inheritDoc}
220 * @since 1.5
221 */
222 @Override
223 public Type[] getGenericParameterTypes() {
224 return super.getGenericParameterTypes();
225 }
226
227 /**
228 * {@inheritDoc}
229 */
230 @Override
231 public Class<?>[] getExceptionTypes() {
232 return exceptionTypes.clone();
233 }
234
235
236 /**
237 * {@inheritDoc}
238 * @throws GenericSignatureFormatError {@inheritDoc}
239 * @throws TypeNotPresentException {@inheritDoc}
240 * @throws MalformedParameterizedTypeException {@inheritDoc}
241 * @since 1.5
242 */
243 @Override
244 public Type[] getGenericExceptionTypes() {
245 return super.getGenericExceptionTypes();
246 }
247
248 /**
249 * Compares this {@code Constructor} against the specified object.
250 * Returns true if the objects are the same. Two {@code Constructor} objects are
251 * the same if they were declared by the same class and have the
252 * same formal parameter types.
253 */
254 public boolean equals(Object obj) {
255 if (obj != null && obj instanceof Constructor) {
256 Constructor<?> other = (Constructor<?>)obj;
257 if (getDeclaringClass() == other.getDeclaringClass()) {
258 return equalParamTypes(parameterTypes, other.parameterTypes);
259 }
260 }
261 return false;
262 }
263
264 /**
265 * Returns a hashcode for this {@code Constructor}. The hashcode is
266 * the same as the hashcode for the underlying constructor's
267 * declaring class name.
268 */
269 public int hashCode() {
270 return getDeclaringClass().getName().hashCode();
271 }
272
273 /**
274 * Returns a string describing this {@code Constructor}. The string is
275 * formatted as the constructor access modifiers, if any,
276 * followed by the fully-qualified name of the declaring class,
277 * followed by a parenthesized, comma-separated list of the
278 * constructor's formal parameter types. For example:
279 * <pre>
280 * public java.util.Hashtable(int,float)
281 * </pre>
282 *
283 * <p>The only possible modifiers for constructors are the access
284 * modifiers {@code public}, {@code protected} or
285 * {@code private}. Only one of these may appear, or none if the
286 * constructor has default (package) access.
287 *
288 * @return a string describing this {@code Constructor}
289 * @jls 8.8.3. Constructor Modifiers
290 */
291 public String toString() {
292 return sharedToString(Modifier.constructorModifiers(),
293 false,
294 parameterTypes,
295 exceptionTypes);
296 }
297
298 @Override
299 void specificToStringHeader(StringBuilder sb) {
300 sb.append(getDeclaringClass().getTypeName());
301 }
302
303 /**
304 * Returns a string describing this {@code Constructor},
305 * including type parameters. The string is formatted as the
306 * constructor access modifiers, if any, followed by an
307 * angle-bracketed comma separated list of the constructor's type
308 * parameters, if any, followed by the fully-qualified name of the
309 * declaring class, followed by a parenthesized, comma-separated
310 * list of the constructor's generic formal parameter types.
311 *
312 * If this constructor was declared to take a variable number of
313 * arguments, instead of denoting the last parameter as
314 * "<tt><i>Type</i>[]</tt>", it is denoted as
315 * "<tt><i>Type</i>...</tt>".
316 *
317 * A space is used to separate access modifiers from one another
318 * and from the type parameters or return type. If there are no
319 * type parameters, the type parameter list is elided; if the type
320 * parameter list is present, a space separates the list from the
321 * class name. If the constructor is declared to throw
322 * exceptions, the parameter list is followed by a space, followed
323 * by the word "{@code throws}" followed by a
324 * comma-separated list of the thrown exception types.
325 *
326 * <p>The only possible modifiers for constructors are the access
327 * modifiers {@code public}, {@code protected} or
328 * {@code private}. Only one of these may appear, or none if the
329 * constructor has default (package) access.
330 *
331 * @return a string describing this {@code Constructor},
332 * include type parameters
333 *
334 * @since 1.5
335 * @jls 8.8.3. Constructor Modifiers
336 */
337 @Override
338 public String toGenericString() {
339 return sharedToGenericString(Modifier.constructorModifiers(), false);
340 }
341
342 @Override
343 void specificToGenericStringHeader(StringBuilder sb) {
344 specificToStringHeader(sb);
345 }
346
347 /**
348 * Uses the constructor represented by this {@code Constructor} object to
349 * create and initialize a new instance of the constructor's
350 * declaring class, with the specified initialization parameters.
351 * Individual parameters are automatically unwrapped to match
352 * primitive formal parameters, and both primitive and reference
353 * parameters are subject to method invocation conversions as necessary.
354 *
355 * <p>If the number of formal parameters required by the underlying constructor
356 * is 0, the supplied {@code initargs} array may be of length 0 or null.
357 *
358 * <p>If the constructor's declaring class is an inner class in a
359 * non-static context, the first argument to the constructor needs
360 * to be the enclosing instance; see section 15.9.3 of
361 * <cite>The Java™ Language Specification</cite>.
362 *
363 * <p>If the required access and argument checks succeed and the
364 * instantiation will proceed, the constructor's declaring class
365 * is initialized if it has not already been initialized.
366 *
367 * <p>If the constructor completes normally, returns the newly
368 * created and initialized instance.
369 *
370 * @param initargs array of objects to be passed as arguments to
371 * the constructor call; values of primitive types are wrapped in
372 * a wrapper object of the appropriate type (e.g. a {@code float}
373 * in a {@link java.lang.Float Float})
374 *
375 * @return a new object created by calling the constructor
376 * this object represents
377 *
378 * @exception IllegalAccessException if this {@code Constructor} object
379 * is enforcing Java language access control and the underlying
380 * constructor is inaccessible.
381 * @exception IllegalArgumentException if the number of actual
382 * and formal parameters differ; if an unwrapping
383 * conversion for primitive arguments fails; or if,
384 * after possible unwrapping, a parameter value
385 * cannot be converted to the corresponding formal
386 * parameter type by a method invocation conversion; if
387 * this constructor pertains to an enum type.
388 * @exception InstantiationException if the class that declares the
389 * underlying constructor represents an abstract class.
390 * @exception InvocationTargetException if the underlying constructor
391 * throws an exception.
392 * @exception ExceptionInInitializerError if the initialization provoked
393 * by this method fails.
394 */
395 public T newInstance(Object ... initargs)
396 throws InstantiationException, IllegalAccessException,
397 IllegalArgumentException, InvocationTargetException
398 {
399 if (!override) {
400 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) {
401 Class<?> caller = Reflection.getCallerClass(2);
402
403 checkAccess(caller, clazz, null, modifiers);
404 }
405 }
406 if ((clazz.getModifiers() & Modifier.ENUM) != 0)
407 throw new IllegalArgumentException("Cannot reflectively create enum objects");
408 ConstructorAccessor ca = constructorAccessor; // read volatile
409 if (ca == null) {
410 ca = acquireConstructorAccessor();
411 }
412 @SuppressWarnings("unchecked")
413 T inst = (T) ca.newInstance(initargs);
414 return inst;
415 }
416
417 /**
418 * {@inheritDoc}
419 * @since 1.5
420 */
421 @Override
422 public boolean isVarArgs() {
423 return super.isVarArgs();
424 }
425
426 /**
427 * {@inheritDoc}
428 * @jls 13.1 The Form of a Binary
429 * @since 1.5
430 */
431 @Override
432 public boolean isSynthetic() {
433 return super.isSynthetic();
434 }
435
436 // NOTE that there is no synchronization used here. It is correct
437 // (though not efficient) to generate more than one
438 // ConstructorAccessor for a given Constructor. However, avoiding
439 // synchronization will probably make the implementation more
440 // scalable.
441 private ConstructorAccessor acquireConstructorAccessor() {
442 // First check to see if one has been created yet, and take it
443 // if so.
444 ConstructorAccessor tmp = null;
445 if (root != null) tmp = root.getConstructorAccessor();
446 if (tmp != null) {
447 constructorAccessor = tmp;
448 } else {
449 // Otherwise fabricate one and propagate it up to the root
450 tmp = reflectionFactory.newConstructorAccessor(this);
451 setConstructorAccessor(tmp);
452 }
453
454 return tmp;
455 }
456
457 // Returns ConstructorAccessor for this Constructor object, not
458 // looking up the chain to the root
459 ConstructorAccessor getConstructorAccessor() {
460 return constructorAccessor;
461 }
462
463 // Sets the ConstructorAccessor for this Constructor object and
464 // (recursively) its root
465 void setConstructorAccessor(ConstructorAccessor accessor) {
466 constructorAccessor = accessor;
467 // Propagate up
468 if (root != null) {
469 root.setConstructorAccessor(accessor);
470 }
471 }
472
473 int getSlot() {
474 return slot;
475 }
476
477 String getSignature() {
478 return signature;
479 }
480
481 byte[] getRawAnnotations() {
482 return annotations;
483 }
484
485 byte[] getRawParameterAnnotations() {
486 return parameterAnnotations;
487 }
488
489
490 /**
491 * {@inheritDoc}
492 * @throws NullPointerException {@inheritDoc}
493 * @since 1.5
494 */
495 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
496 return super.getAnnotation(annotationClass);
497 }
498
499 /**
500 * {@inheritDoc}
501 * @since 1.5
502 */
503 public Annotation[] getDeclaredAnnotations() {
504 return super.getDeclaredAnnotations();
505 }
506
507 /**
508 * {@inheritDoc}
509 * @since 1.5
510 */
511 @Override
512 public Annotation[][] getParameterAnnotations() {
513 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations);
514 }
515
516 @Override
517 void handleParameterNumberMismatch(int resultLength, int numParameters) {
518 Class<?> declaringClass = getDeclaringClass();
519 if (declaringClass.isEnum() ||
520 declaringClass.isAnonymousClass() ||
521 declaringClass.isLocalClass() )
522 return ; // Can't do reliable parameter counting
523 else {
524 if (!declaringClass.isMemberClass() || // top-level
525 // Check for the enclosing instance parameter for
526 // non-static member classes
527 (declaringClass.isMemberClass() &&
528 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) &&
529 resultLength + 1 != numParameters) ) {
530 throw new AnnotationFormatError(
531 "Parameter annotations don't match number of parameters");
532 }
533 }
534 }
535
536 /**
537 * {@inheritDoc}
538 * @since 1.8
539 */
540 @Override
541 public AnnotatedType getAnnotatedReturnType() {
542 return getAnnotatedReturnType0(getDeclaringClass());
543 }
544 }