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 sun.reflect.CallerSensitive; 30 import sun.reflect.ConstructorAccessor; 31 import sun.reflect.Reflection; 32 import sun.reflect.annotation.TypeAnnotation; 33 import sun.reflect.annotation.TypeAnnotationParser; 34 import sun.reflect.generics.repository.ConstructorRepository; 35 import sun.reflect.generics.factory.CoreReflectionFactory; 36 import sun.reflect.generics.factory.GenericsFactory; 37 import sun.reflect.generics.scope.ConstructorScope; 38 import java.lang.annotation.Annotation; 39 import java.lang.annotation.AnnotationFormatError; 40 41 /** 42 * {@code Constructor} provides information about, and access to, a single 43 * constructor for a class. 44 * 45 * <p>{@code Constructor} permits widening conversions to occur when matching the 46 * actual parameters to newInstance() with the underlying 47 * constructor's formal parameters, but throws an 48 * {@code IllegalArgumentException} if a narrowing conversion would occur. 49 * 50 * @param <T> the class in which the constructor is declared 51 * 52 * @see Member 53 * @see java.lang.Class 54 * @see java.lang.Class#getConstructors() 55 * @see java.lang.Class#getConstructor(Class[]) 56 * @see java.lang.Class#getDeclaredConstructors() 57 * 58 * @author Kenneth Russell 59 * @author Nakul Saraiya 60 */ 61 public final class Constructor<T> extends Executable { 62 private Class<T> clazz; 63 private int slot; 64 private Class<?>[] parameterTypes; 65 private Class<?>[] exceptionTypes; 66 private int modifiers; 67 // Generics and annotations support 68 private transient String signature; 69 // generic info repository; lazily initialized 70 private transient ConstructorRepository genericInfo; 71 private byte[] annotations; 72 private byte[] parameterAnnotations; 73 74 // Generics infrastructure 75 // Accessor for factory 76 private GenericsFactory getFactory() { 77 // create scope and factory 78 return CoreReflectionFactory.make(this, ConstructorScope.make(this)); 79 } 80 81 // Accessor for generic info repository 82 @Override 83 ConstructorRepository getGenericInfo() { 84 // lazily initialize repository if necessary 85 if (genericInfo == null) { 86 // create and cache generic info repository 87 genericInfo = 88 ConstructorRepository.make(getSignature(), 89 getFactory()); 90 } 91 return genericInfo; //return cached repository 92 } 93 94 private volatile ConstructorAccessor constructorAccessor; 95 // For sharing of ConstructorAccessors. This branching structure 96 // is currently only two levels deep (i.e., one root Constructor 97 // and potentially many Constructor objects pointing to it.) 98 // 99 // If this branching structure would ever contain cycles, deadlocks can 100 // occur in annotation code. 101 private Constructor<T> root; 102 103 /** 104 * Used by Excecutable for annotation sharing. 105 */ 106 @Override 107 Executable getRoot() { 108 return root; 109 } 110 111 /** 112 * Package-private constructor used by ReflectAccess to enable 113 * instantiation of these objects in Java code from the java.lang 114 * package via sun.reflect.LangReflectAccess. 115 */ 116 Constructor(Class<T> declaringClass, 117 Class<?>[] parameterTypes, 118 Class<?>[] checkedExceptions, 119 int modifiers, 120 int slot, 121 String signature, 122 byte[] annotations, 123 byte[] parameterAnnotations) { 124 this.clazz = declaringClass; 125 this.parameterTypes = parameterTypes; 126 this.exceptionTypes = checkedExceptions; 127 this.modifiers = modifiers; 128 this.slot = slot; 129 this.signature = signature; 130 this.annotations = annotations; 131 this.parameterAnnotations = parameterAnnotations; 132 } 133 134 /** 135 * Package-private routine (exposed to java.lang.Class via 136 * ReflectAccess) which returns a copy of this Constructor. The copy's 137 * "root" field points to this Constructor. 138 */ 139 Constructor<T> copy() { 140 // This routine enables sharing of ConstructorAccessor objects 141 // among Constructor objects which refer to the same underlying 142 // method in the VM. (All of this contortion is only necessary 143 // because of the "accessibility" bit in AccessibleObject, 144 // which implicitly requires that new java.lang.reflect 145 // objects be fabricated for each reflective call on Class 146 // objects.) 147 if (this.root != null) 148 throw new IllegalArgumentException("Can not copy a non-root Constructor"); 149 150 Constructor<T> res = new Constructor<>(clazz, 151 parameterTypes, 152 exceptionTypes, modifiers, slot, 153 signature, 154 annotations, 155 parameterAnnotations); 156 res.root = this; 157 // Might as well eagerly propagate this if already present 158 res.constructorAccessor = constructorAccessor; 159 return res; 160 } 161 162 @Override 163 boolean hasGenericInformation() { 164 return (getSignature() != null); 165 } 166 167 @Override 168 byte[] getAnnotationBytes() { 169 return annotations; 170 } 171 172 /** 173 * {@inheritDoc} 174 */ 175 @Override 176 public Class<T> getDeclaringClass() { 177 return clazz; 178 } 179 180 /** 181 * Returns the name of this constructor, as a string. This is 182 * the binary name of the constructor's declaring class. 183 */ 184 @Override 185 public String getName() { 186 return getDeclaringClass().getName(); 187 } 188 189 /** 190 * {@inheritDoc} 191 */ 192 @Override 193 public int getModifiers() { 194 return modifiers; 195 } 196 197 /** 198 * {@inheritDoc} 199 * @throws GenericSignatureFormatError {@inheritDoc} 200 * @since 1.5 201 */ 202 @Override 203 @SuppressWarnings({"rawtypes", "unchecked"}) 204 public TypeVariable<Constructor<T>>[] getTypeParameters() { 205 if (getSignature() != null) { 206 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 207 } else 208 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 209 } 210 211 212 /** 213 * {@inheritDoc} 214 */ 215 @Override 216 public Class<?>[] getParameterTypes() { 217 return parameterTypes.clone(); 218 } 219 220 /** 221 * {@inheritDoc} 222 * @since 1.8 223 */ 224 public int getParameterCount() { return parameterTypes.length; } 225 226 /** 227 * {@inheritDoc} 228 * @throws GenericSignatureFormatError {@inheritDoc} 229 * @throws TypeNotPresentException {@inheritDoc} 230 * @throws MalformedParameterizedTypeException {@inheritDoc} 231 * @since 1.5 232 */ 233 @Override 234 public Type[] getGenericParameterTypes() { 235 return super.getGenericParameterTypes(); 236 } 237 238 /** 239 * {@inheritDoc} 240 */ 241 @Override 242 public Class<?>[] getExceptionTypes() { 243 return exceptionTypes.clone(); 244 } 245 246 247 /** 248 * {@inheritDoc} 249 * @throws GenericSignatureFormatError {@inheritDoc} 250 * @throws TypeNotPresentException {@inheritDoc} 251 * @throws MalformedParameterizedTypeException {@inheritDoc} 252 * @since 1.5 253 */ 254 @Override 255 public Type[] getGenericExceptionTypes() { 256 return super.getGenericExceptionTypes(); 257 } 258 259 /** 260 * Compares this {@code Constructor} against the specified object. 261 * Returns true if the objects are the same. Two {@code Constructor} objects are 262 * the same if they were declared by the same class and have the 263 * same formal parameter types. 264 */ 265 public boolean equals(Object obj) { 266 if (obj != null && obj instanceof Constructor) { 267 Constructor<?> other = (Constructor<?>)obj; 268 if (getDeclaringClass() == other.getDeclaringClass()) { 269 return equalParamTypes(parameterTypes, other.parameterTypes); 270 } 271 } 272 return false; 273 } 274 275 /** 276 * Returns a hashcode for this {@code Constructor}. The hashcode is 277 * the same as the hashcode for the underlying constructor's 278 * declaring class name. 279 */ 280 public int hashCode() { 281 return getDeclaringClass().getName().hashCode(); 282 } 283 284 /** 285 * Returns a string describing this {@code Constructor}. The string is 286 * formatted as the constructor access modifiers, if any, 287 * followed by the fully-qualified name of the declaring class, 288 * followed by a parenthesized, comma-separated list of the 289 * constructor's formal parameter types. For example: 290 * <pre>{@code 291 * public java.util.Hashtable(int,float) 292 * }</pre> 293 * 294 * <p>The only possible modifiers for constructors are the access 295 * modifiers {@code public}, {@code protected} or 296 * {@code private}. Only one of these may appear, or none if the 297 * constructor has default (package) access. 298 * 299 * @return a string describing this {@code Constructor} 300 * @jls 8.8.3 Constructor Modifiers 301 * @jls 8.9.2 Enum Body Declarations 302 */ 303 public String toString() { 304 return sharedToString(Modifier.constructorModifiers(), 305 false, 306 parameterTypes, 307 exceptionTypes); 308 } 309 310 @Override 311 void specificToStringHeader(StringBuilder sb) { 312 sb.append(getDeclaringClass().getTypeName()); 313 } 314 315 /** 316 * Returns a string describing this {@code Constructor}, 317 * including type parameters. The string is formatted as the 318 * constructor access modifiers, if any, followed by an 319 * angle-bracketed comma separated list of the constructor's type 320 * parameters, if any, followed by the fully-qualified name of the 321 * declaring class, followed by a parenthesized, comma-separated 322 * list of the constructor's generic formal parameter types. 323 * 324 * If this constructor was declared to take a variable number of 325 * arguments, instead of denoting the last parameter as 326 * "<code><i>Type</i>[]</code>", it is denoted as 327 * "<code><i>Type</i>...</code>". 328 * 329 * A space is used to separate access modifiers from one another 330 * and from the type parameters or return type. If there are no 331 * type parameters, the type parameter list is elided; if the type 332 * parameter list is present, a space separates the list from the 333 * class name. If the constructor is declared to throw 334 * exceptions, the parameter list is followed by a space, followed 335 * by the word "{@code throws}" followed by a 336 * comma-separated list of the thrown exception types. 337 * 338 * <p>The only possible modifiers for constructors are the access 339 * modifiers {@code public}, {@code protected} or 340 * {@code private}. Only one of these may appear, or none if the 341 * constructor has default (package) access. 342 * 343 * @return a string describing this {@code Constructor}, 344 * include type parameters 345 * 346 * @since 1.5 347 * @jls 8.8.3 Constructor Modifiers 348 * @jls 8.9.2 Enum Body Declarations 349 */ 350 @Override 351 public String toGenericString() { 352 return sharedToGenericString(Modifier.constructorModifiers(), false); 353 } 354 355 @Override 356 void specificToGenericStringHeader(StringBuilder sb) { 357 specificToStringHeader(sb); 358 } 359 360 /** 361 * Uses the constructor represented by this {@code Constructor} object to 362 * create and initialize a new instance of the constructor's 363 * declaring class, with the specified initialization parameters. 364 * Individual parameters are automatically unwrapped to match 365 * primitive formal parameters, and both primitive and reference 366 * parameters are subject to method invocation conversions as necessary. 367 * 368 * <p>If the number of formal parameters required by the underlying constructor 369 * is 0, the supplied {@code initargs} array may be of length 0 or null. 370 * 371 * <p>If the constructor's declaring class is an inner class in a 372 * non-static context, the first argument to the constructor needs 373 * to be the enclosing instance; see section 15.9.3 of 374 * <cite>The Java™ Language Specification</cite>. 375 * 376 * <p>If the required access and argument checks succeed and the 377 * instantiation will proceed, the constructor's declaring class 378 * is initialized if it has not already been initialized. 379 * 380 * <p>If the constructor completes normally, returns the newly 381 * created and initialized instance. 382 * 383 * @param initargs array of objects to be passed as arguments to 384 * the constructor call; values of primitive types are wrapped in 385 * a wrapper object of the appropriate type (e.g. a {@code float} 386 * in a {@link java.lang.Float Float}) 387 * 388 * @return a new object created by calling the constructor 389 * this object represents 390 * 391 * @exception IllegalAccessException if this {@code Constructor} object 392 * is enforcing Java language access control and the underlying 393 * constructor is inaccessible. 394 * @exception IllegalArgumentException if the number of actual 395 * and formal parameters differ; if an unwrapping 396 * conversion for primitive arguments fails; or if, 397 * after possible unwrapping, a parameter value 398 * cannot be converted to the corresponding formal 399 * parameter type by a method invocation conversion; if 400 * this constructor pertains to an enum type. 401 * @exception InstantiationException if the class that declares the 402 * underlying constructor represents an abstract class. 403 * @exception InvocationTargetException if the underlying constructor 404 * throws an exception. 405 * @exception ExceptionInInitializerError if the initialization provoked 406 * by this method fails. 407 */ 408 @CallerSensitive 409 public T newInstance(Object ... initargs) 410 throws InstantiationException, IllegalAccessException, 411 IllegalArgumentException, InvocationTargetException 412 { 413 if (!override) { 414 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 415 Class<?> caller = Reflection.getCallerClass(); 416 checkAccess(caller, clazz, null, modifiers); 417 } 418 } 419 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 420 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 421 ConstructorAccessor ca = constructorAccessor; // read volatile 422 if (ca == null) { 423 ca = acquireConstructorAccessor(); 424 } 425 @SuppressWarnings("unchecked") 426 T inst = (T) ca.newInstance(initargs); 427 return inst; 428 } 429 430 /** 431 * {@inheritDoc} 432 * @since 1.5 433 */ 434 @Override 435 public boolean isVarArgs() { 436 return super.isVarArgs(); 437 } 438 439 /** 440 * {@inheritDoc} 441 * @jls 13.1 The Form of a Binary 442 * @since 1.5 443 */ 444 @Override 445 public boolean isSynthetic() { 446 return super.isSynthetic(); 447 } 448 449 // NOTE that there is no synchronization used here. It is correct 450 // (though not efficient) to generate more than one 451 // ConstructorAccessor for a given Constructor. However, avoiding 452 // synchronization will probably make the implementation more 453 // scalable. 454 private ConstructorAccessor acquireConstructorAccessor() { 455 // First check to see if one has been created yet, and take it 456 // if so. 457 ConstructorAccessor tmp = null; 458 if (root != null) tmp = root.getConstructorAccessor(); 459 if (tmp != null) { 460 constructorAccessor = tmp; 461 } else { 462 // Otherwise fabricate one and propagate it up to the root 463 tmp = reflectionFactory.newConstructorAccessor(this); 464 setConstructorAccessor(tmp); 465 } 466 467 return tmp; 468 } 469 470 // Returns ConstructorAccessor for this Constructor object, not 471 // looking up the chain to the root 472 ConstructorAccessor getConstructorAccessor() { 473 return constructorAccessor; 474 } 475 476 // Sets the ConstructorAccessor for this Constructor object and 477 // (recursively) its root 478 void setConstructorAccessor(ConstructorAccessor accessor) { 479 constructorAccessor = accessor; 480 // Propagate up 481 if (root != null) { 482 root.setConstructorAccessor(accessor); 483 } 484 } 485 486 int getSlot() { 487 return slot; 488 } 489 490 String getSignature() { 491 return signature; 492 } 493 494 byte[] getRawAnnotations() { 495 return annotations; 496 } 497 498 byte[] getRawParameterAnnotations() { 499 return parameterAnnotations; 500 } 501 502 503 /** 504 * {@inheritDoc} 505 * @throws NullPointerException {@inheritDoc} 506 * @since 1.5 507 */ 508 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 509 return super.getAnnotation(annotationClass); 510 } 511 512 /** 513 * {@inheritDoc} 514 * @since 1.5 515 */ 516 public Annotation[] getDeclaredAnnotations() { 517 return super.getDeclaredAnnotations(); 518 } 519 520 /** 521 * {@inheritDoc} 522 * @since 1.5 523 */ 524 @Override 525 public Annotation[][] getParameterAnnotations() { 526 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 527 } 528 529 @Override 530 void handleParameterNumberMismatch(int resultLength, int numParameters) { 531 Class<?> declaringClass = getDeclaringClass(); 532 if (declaringClass.isEnum() || 533 declaringClass.isAnonymousClass() || 534 declaringClass.isLocalClass() ) 535 return ; // Can't do reliable parameter counting 536 else { 537 if (!declaringClass.isMemberClass() || // top-level 538 // Check for the enclosing instance parameter for 539 // non-static member classes 540 (declaringClass.isMemberClass() && 541 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 542 resultLength + 1 != numParameters) ) { 543 throw new AnnotationFormatError( 544 "Parameter annotations don't match number of parameters"); 545 } 546 } 547 } 548 549 /** 550 * {@inheritDoc} 551 * @since 1.8 552 */ 553 @Override 554 public AnnotatedType getAnnotatedReturnType() { 555 return getAnnotatedReturnType0(getDeclaringClass()); 556 } 557 558 /** 559 * {@inheritDoc} 560 * @since 1.8 561 */ 562 @Override 563 public AnnotatedType getAnnotatedReceiverType() { 564 Class<?> thisDeclClass = getDeclaringClass(); 565 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 566 567 if (enclosingClass == null) { 568 // A Constructor for a top-level class 569 return null; 570 } 571 572 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 573 if (outerDeclaringClass == null) { 574 // A constructor for a local or anonymous class 575 return null; 576 } 577 578 // Either static nested or inner class 579 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 580 // static nested 581 return null; 582 } 583 584 // A Constructor for an inner class 585 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 586 SharedSecrets.getJavaLangAccess(). 587 getConstantPool(thisDeclClass), 588 this, 589 thisDeclClass, 590 enclosingClass, 591 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 592 } 593 }