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 jdk.internal.reflect.CallerSensitive; 30 import jdk.internal.reflect.ConstructorAccessor; 31 import jdk.internal.reflect.Reflection; 32 import jdk.internal.vm.annotation.ForceInline; 33 import sun.reflect.annotation.TypeAnnotation; 34 import sun.reflect.annotation.TypeAnnotationParser; 35 import sun.reflect.generics.repository.ConstructorRepository; 36 import sun.reflect.generics.factory.CoreReflectionFactory; 37 import sun.reflect.generics.factory.GenericsFactory; 38 import sun.reflect.generics.scope.ConstructorScope; 39 import java.lang.annotation.Annotation; 40 import java.lang.annotation.AnnotationFormatError; 41 42 /** 43 * {@code Constructor} provides information about, and access to, a single 44 * constructor for a class. 45 * 46 * <p>{@code Constructor} permits widening conversions to occur when matching the 47 * actual parameters to newInstance() with the underlying 48 * constructor's formal parameters, but throws an 49 * {@code IllegalArgumentException} if a narrowing conversion would occur. 50 * 51 * @param <T> the class in which the constructor is declared 52 * 53 * @see Member 54 * @see java.lang.Class 55 * @see java.lang.Class#getConstructors() 56 * @see java.lang.Class#getConstructor(Class[]) 57 * @see java.lang.Class#getDeclaredConstructors() 58 * 59 * @author Kenneth Russell 60 * @author Nakul Saraiya 61 */ 62 public final class Constructor<T> extends Executable { 63 private Class<T> clazz; 64 private int slot; 65 private Class<?>[] parameterTypes; 66 private Class<?>[] exceptionTypes; 67 private int modifiers; 68 // Generics and annotations support 69 private transient String signature; 70 // generic info repository; lazily initialized 71 private transient ConstructorRepository genericInfo; 72 private byte[] annotations; 73 private byte[] parameterAnnotations; 74 75 // Generics infrastructure 76 // Accessor for factory 77 private GenericsFactory getFactory() { 78 // create scope and factory 79 return CoreReflectionFactory.make(this, ConstructorScope.make(this)); 80 } 81 82 // Accessor for generic info repository 83 @Override 84 ConstructorRepository getGenericInfo() { 85 // lazily initialize repository if necessary 86 if (genericInfo == null) { 87 // create and cache generic info repository 88 genericInfo = 89 ConstructorRepository.make(getSignature(), 90 getFactory()); 91 } 92 return genericInfo; //return cached repository 93 } 94 95 private volatile ConstructorAccessor constructorAccessor; 96 // For sharing of ConstructorAccessors. This branching structure 97 // is currently only two levels deep (i.e., one root Constructor 98 // and potentially many Constructor objects pointing to it.) 99 // 100 // If this branching structure would ever contain cycles, deadlocks can 101 // occur in annotation code. 102 private Constructor<T> root; 103 104 /** 105 * Used by Excecutable for annotation sharing. 106 */ 107 @Override 108 Executable getRoot() { 109 return root; 110 } 111 112 /** 113 * Package-private constructor used by ReflectAccess to enable 114 * instantiation of these objects in Java code from the java.lang 115 * package via sun.reflect.LangReflectAccess. 116 */ 117 Constructor(Class<T> declaringClass, 118 Class<?>[] parameterTypes, 119 Class<?>[] checkedExceptions, 120 int modifiers, 121 int slot, 122 String signature, 123 byte[] annotations, 124 byte[] parameterAnnotations) { 125 this.clazz = declaringClass; 126 this.parameterTypes = parameterTypes; 127 this.exceptionTypes = checkedExceptions; 128 this.modifiers = modifiers; 129 this.slot = slot; 130 this.signature = signature; 131 this.annotations = annotations; 132 this.parameterAnnotations = parameterAnnotations; 133 } 134 135 /** 136 * Package-private routine (exposed to java.lang.Class via 137 * ReflectAccess) which returns a copy of this Constructor. The copy's 138 * "root" field points to this Constructor. 139 */ 140 Constructor<T> copy() { 141 // This routine enables sharing of ConstructorAccessor objects 142 // among Constructor objects which refer to the same underlying 143 // method in the VM. (All of this contortion is only necessary 144 // because of the "accessibility" bit in AccessibleObject, 145 // which implicitly requires that new java.lang.reflect 146 // objects be fabricated for each reflective call on Class 147 // objects.) 148 if (this.root != null) 149 throw new IllegalArgumentException("Can not copy a non-root Constructor"); 150 151 Constructor<T> res = new Constructor<>(clazz, 152 parameterTypes, 153 exceptionTypes, modifiers, slot, 154 signature, 155 annotations, 156 parameterAnnotations); 157 res.root = this; 158 // Might as well eagerly propagate this if already present 159 res.constructorAccessor = constructorAccessor; 160 return res; 161 } 162 163 /** 164 * {@inheritDoc} 165 * 166 * <p> A {@code SecurityException} is also thrown if this object is a 167 * {@code Constructor} object for the class {@code Class} and {@code flag} 168 * is true. </p> 169 * 170 * @param flag {@inheritDoc} 171 */ 172 @Override 173 @CallerSensitive 174 public void setAccessible(boolean flag) { 175 AccessibleObject.checkPermission(); 176 if (flag) { 177 checkCanSetAccessible(Reflection.getCallerClass()); 178 } 179 setAccessible0(flag); 180 } 181 182 @Override 183 void checkCanSetAccessible(Class<?> caller) { 184 checkCanSetAccessible(caller, clazz); 185 if (clazz == Class.class) { 186 // can we change this to InaccessibleObjectException? 187 throw new SecurityException("Cannot make a java.lang.Class" 188 + " constructor accessible"); 189 } 190 } 191 192 @Override 193 boolean hasGenericInformation() { 194 return (getSignature() != null); 195 } 196 197 @Override 198 byte[] getAnnotationBytes() { 199 return annotations; 200 } 201 202 /** 203 * Returns the {@code Class} object representing the class that 204 * declares the constructor represented by this object. 205 */ 206 @Override 207 public Class<T> getDeclaringClass() { 208 return clazz; 209 } 210 211 /** 212 * Returns the name of this constructor, as a string. This is 213 * the binary name of the constructor's declaring class. 214 */ 215 @Override 216 public String getName() { 217 return getDeclaringClass().getName(); 218 } 219 220 /** 221 * {@inheritDoc} 222 */ 223 @Override 224 public int getModifiers() { 225 return modifiers; 226 } 227 228 /** 229 * {@inheritDoc} 230 * @throws GenericSignatureFormatError {@inheritDoc} 231 * @since 1.5 232 */ 233 @Override 234 @SuppressWarnings({"rawtypes", "unchecked"}) 235 public TypeVariable<Constructor<T>>[] getTypeParameters() { 236 if (getSignature() != null) { 237 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 238 } else 239 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 240 } 241 242 243 /** 244 * {@inheritDoc} 245 */ 246 @Override 247 public Class<?>[] getParameterTypes() { 248 return parameterTypes.clone(); 249 } 250 251 /** 252 * {@inheritDoc} 253 * @since 1.8 254 */ 255 public int getParameterCount() { return parameterTypes.length; } 256 257 /** 258 * {@inheritDoc} 259 * @throws GenericSignatureFormatError {@inheritDoc} 260 * @throws TypeNotPresentException {@inheritDoc} 261 * @throws MalformedParameterizedTypeException {@inheritDoc} 262 * @since 1.5 263 */ 264 @Override 265 public Type[] getGenericParameterTypes() { 266 return super.getGenericParameterTypes(); 267 } 268 269 /** 270 * {@inheritDoc} 271 */ 272 @Override 273 public Class<?>[] getExceptionTypes() { 274 return exceptionTypes.clone(); 275 } 276 277 278 /** 279 * {@inheritDoc} 280 * @throws GenericSignatureFormatError {@inheritDoc} 281 * @throws TypeNotPresentException {@inheritDoc} 282 * @throws MalformedParameterizedTypeException {@inheritDoc} 283 * @since 1.5 284 */ 285 @Override 286 public Type[] getGenericExceptionTypes() { 287 return super.getGenericExceptionTypes(); 288 } 289 290 /** 291 * Compares this {@code Constructor} against the specified object. 292 * Returns true if the objects are the same. Two {@code Constructor} objects are 293 * the same if they were declared by the same class and have the 294 * same formal parameter types. 295 */ 296 public boolean equals(Object obj) { 297 if (obj != null && obj instanceof Constructor) { 298 Constructor<?> other = (Constructor<?>)obj; 299 if (getDeclaringClass() == other.getDeclaringClass()) { 300 return equalParamTypes(parameterTypes, other.parameterTypes); 301 } 302 } 303 return false; 304 } 305 306 /** 307 * Returns a hashcode for this {@code Constructor}. The hashcode is 308 * the same as the hashcode for the underlying constructor's 309 * declaring class name. 310 */ 311 public int hashCode() { 312 return getDeclaringClass().getName().hashCode(); 313 } 314 315 /** 316 * Returns a string describing this {@code Constructor}. The string is 317 * formatted as the constructor access modifiers, if any, 318 * followed by the fully-qualified name of the declaring class, 319 * followed by a parenthesized, comma-separated list of the 320 * constructor's formal parameter types. For example: 321 * <pre>{@code 322 * public java.util.Hashtable(int,float) 323 * }</pre> 324 * 325 * <p>If the constructor is declared to throw exceptions, the 326 * parameter list is followed by a space, followed by the word 327 * "{@code throws}" followed by a comma-separated list of the 328 * thrown exception types. 329 * 330 * <p>The only possible modifiers for constructors are the access 331 * modifiers {@code public}, {@code protected} or 332 * {@code private}. Only one of these may appear, or none if the 333 * constructor has default (package) access. 334 * 335 * @return a string describing this {@code Constructor} 336 * @jls 8.8.3 Constructor Modifiers 337 * @jls 8.9.2 Enum Body Declarations 338 */ 339 public String toString() { 340 return sharedToString(Modifier.constructorModifiers(), 341 false, 342 parameterTypes, 343 exceptionTypes); 344 } 345 346 @Override 347 void specificToStringHeader(StringBuilder sb) { 348 sb.append(getDeclaringClass().getTypeName()); 349 } 350 351 /** 352 * Returns a string describing this {@code Constructor}, 353 * including type parameters. The string is formatted as the 354 * constructor access modifiers, if any, followed by an 355 * angle-bracketed comma separated list of the constructor's type 356 * parameters, if any, followed by the fully-qualified name of the 357 * declaring class, followed by a parenthesized, comma-separated 358 * list of the constructor's generic formal parameter types. 359 * 360 * If this constructor was declared to take a variable number of 361 * arguments, instead of denoting the last parameter as 362 * "<code><i>Type</i>[]</code>", it is denoted as 363 * "<code><i>Type</i>...</code>". 364 * 365 * A space is used to separate access modifiers from one another 366 * and from the type parameters or class name. If there are no 367 * type parameters, the type parameter list is elided; if the type 368 * parameter list is present, a space separates the list from the 369 * class name. If the constructor is declared to throw 370 * exceptions, the parameter list is followed by a space, followed 371 * by the word "{@code throws}" followed by a 372 * comma-separated list of the generic thrown exception types. 373 * 374 * <p>The only possible modifiers for constructors are the access 375 * modifiers {@code public}, {@code protected} or 376 * {@code private}. Only one of these may appear, or none if the 377 * constructor has default (package) access. 378 * 379 * @return a string describing this {@code Constructor}, 380 * include type parameters 381 * 382 * @since 1.5 383 * @jls 8.8.3 Constructor Modifiers 384 * @jls 8.9.2 Enum Body Declarations 385 */ 386 @Override 387 public String toGenericString() { 388 return sharedToGenericString(Modifier.constructorModifiers(), false); 389 } 390 391 @Override 392 void specificToGenericStringHeader(StringBuilder sb) { 393 specificToStringHeader(sb); 394 } 395 396 /** 397 * Uses the constructor represented by this {@code Constructor} object to 398 * create and initialize a new instance of the constructor's 399 * declaring class, with the specified initialization parameters. 400 * Individual parameters are automatically unwrapped to match 401 * primitive formal parameters, and both primitive and reference 402 * parameters are subject to method invocation conversions as necessary. 403 * 404 * <p>If the number of formal parameters required by the underlying constructor 405 * is 0, the supplied {@code initargs} array may be of length 0 or null. 406 * 407 * <p>If the constructor's declaring class is an inner class in a 408 * non-static context, the first argument to the constructor needs 409 * to be the enclosing instance; see section 15.9.3 of 410 * <cite>The Java™ Language Specification</cite>. 411 * 412 * <p>If the required access and argument checks succeed and the 413 * instantiation will proceed, the constructor's declaring class 414 * is initialized if it has not already been initialized. 415 * 416 * <p>If the constructor completes normally, returns the newly 417 * created and initialized instance. 418 * 419 * @param initargs array of objects to be passed as arguments to 420 * the constructor call; values of primitive types are wrapped in 421 * a wrapper object of the appropriate type (e.g. a {@code float} 422 * in a {@link java.lang.Float Float}) 423 * 424 * @return a new object created by calling the constructor 425 * this object represents 426 * 427 * @exception IllegalAccessException if this {@code Constructor} object 428 * is enforcing Java language access control and the underlying 429 * constructor is inaccessible. 430 * @exception IllegalArgumentException if the number of actual 431 * and formal parameters differ; if an unwrapping 432 * conversion for primitive arguments fails; or if, 433 * after possible unwrapping, a parameter value 434 * cannot be converted to the corresponding formal 435 * parameter type by a method invocation conversion; if 436 * this constructor pertains to an enum type. 437 * @exception InstantiationException if the class that declares the 438 * underlying constructor represents an abstract class. 439 * @exception InvocationTargetException if the underlying constructor 440 * throws an exception. 441 * @exception ExceptionInInitializerError if the initialization provoked 442 * by this method fails. 443 */ 444 @CallerSensitive 445 @ForceInline // to ensure Reflection.getCallerClass optimization 446 public T newInstance(Object ... initargs) 447 throws InstantiationException, IllegalAccessException, 448 IllegalArgumentException, InvocationTargetException 449 { 450 if (!override) { 451 Class<?> caller = Reflection.getCallerClass(); 452 checkAccess(caller, clazz, clazz, modifiers); 453 } 454 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 455 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 456 ConstructorAccessor ca = constructorAccessor; // read volatile 457 if (ca == null) { 458 ca = acquireConstructorAccessor(); 459 } 460 @SuppressWarnings("unchecked") 461 T inst = (T) ca.newInstance(initargs); 462 return inst; 463 } 464 465 /** 466 * {@inheritDoc} 467 * @since 1.5 468 */ 469 @Override 470 public boolean isVarArgs() { 471 return super.isVarArgs(); 472 } 473 474 /** 475 * {@inheritDoc} 476 * @jls 13.1 The Form of a Binary 477 * @since 1.5 478 */ 479 @Override 480 public boolean isSynthetic() { 481 return super.isSynthetic(); 482 } 483 484 // NOTE that there is no synchronization used here. It is correct 485 // (though not efficient) to generate more than one 486 // ConstructorAccessor for a given Constructor. However, avoiding 487 // synchronization will probably make the implementation more 488 // scalable. 489 private ConstructorAccessor acquireConstructorAccessor() { 490 // First check to see if one has been created yet, and take it 491 // if so. 492 ConstructorAccessor tmp = null; 493 if (root != null) tmp = root.getConstructorAccessor(); 494 if (tmp != null) { 495 constructorAccessor = tmp; 496 } else { 497 // Otherwise fabricate one and propagate it up to the root 498 tmp = reflectionFactory.newConstructorAccessor(this); 499 setConstructorAccessor(tmp); 500 } 501 502 return tmp; 503 } 504 505 // Returns ConstructorAccessor for this Constructor object, not 506 // looking up the chain to the root 507 ConstructorAccessor getConstructorAccessor() { 508 return constructorAccessor; 509 } 510 511 // Sets the ConstructorAccessor for this Constructor object and 512 // (recursively) its root 513 void setConstructorAccessor(ConstructorAccessor accessor) { 514 constructorAccessor = accessor; 515 // Propagate up 516 if (root != null) { 517 root.setConstructorAccessor(accessor); 518 } 519 } 520 521 int getSlot() { 522 return slot; 523 } 524 525 String getSignature() { 526 return signature; 527 } 528 529 byte[] getRawAnnotations() { 530 return annotations; 531 } 532 533 byte[] getRawParameterAnnotations() { 534 return parameterAnnotations; 535 } 536 537 538 /** 539 * {@inheritDoc} 540 * @throws NullPointerException {@inheritDoc} 541 * @since 1.5 542 */ 543 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 544 return super.getAnnotation(annotationClass); 545 } 546 547 /** 548 * {@inheritDoc} 549 * @since 1.5 550 */ 551 public Annotation[] getDeclaredAnnotations() { 552 return super.getDeclaredAnnotations(); 553 } 554 555 /** 556 * {@inheritDoc} 557 * @since 1.5 558 */ 559 @Override 560 public Annotation[][] getParameterAnnotations() { 561 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 562 } 563 564 @Override 565 void handleParameterNumberMismatch(int resultLength, int numParameters) { 566 Class<?> declaringClass = getDeclaringClass(); 567 if (declaringClass.isEnum() || 568 declaringClass.isAnonymousClass() || 569 declaringClass.isLocalClass() ) 570 return ; // Can't do reliable parameter counting 571 else { 572 if (!declaringClass.isMemberClass() || // top-level 573 // Check for the enclosing instance parameter for 574 // non-static member classes 575 (declaringClass.isMemberClass() && 576 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 577 resultLength + 1 != numParameters) ) { 578 throw new AnnotationFormatError( 579 "Parameter annotations don't match number of parameters"); 580 } 581 } 582 } 583 584 /** 585 * {@inheritDoc} 586 * @since 1.8 587 */ 588 @Override 589 public AnnotatedType getAnnotatedReturnType() { 590 return getAnnotatedReturnType0(getDeclaringClass()); 591 } 592 593 /** 594 * {@inheritDoc} 595 * @since 1.8 596 */ 597 @Override 598 public AnnotatedType getAnnotatedReceiverType() { 599 Class<?> thisDeclClass = getDeclaringClass(); 600 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 601 602 if (enclosingClass == null) { 603 // A Constructor for a top-level class 604 return null; 605 } 606 607 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 608 if (outerDeclaringClass == null) { 609 // A constructor for a local or anonymous class 610 return null; 611 } 612 613 // Either static nested or inner class 614 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 615 // static nested 616 return null; 617 } 618 619 // A Constructor for an inner class 620 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 621 SharedSecrets.getJavaLangAccess(). 622 getConstantPool(thisDeclClass), 623 this, 624 thisDeclClass, 625 enclosingClass, 626 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 627 } 628 }