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 * {@inheritDoc} 204 */ 205 @Override 206 public Class<T> getDeclaringClass() { 207 return clazz; 208 } 209 210 /** 211 * Returns the name of this constructor, as a string. This is 212 * the binary name of the constructor's declaring class. 213 */ 214 @Override 215 public String getName() { 216 return getDeclaringClass().getName(); 217 } 218 219 /** 220 * {@inheritDoc} 221 */ 222 @Override 223 public int getModifiers() { 224 return modifiers; 225 } 226 227 /** 228 * {@inheritDoc} 229 * @throws GenericSignatureFormatError {@inheritDoc} 230 * @since 1.5 231 */ 232 @Override 233 @SuppressWarnings({"rawtypes", "unchecked"}) 234 public TypeVariable<Constructor<T>>[] getTypeParameters() { 235 if (getSignature() != null) { 236 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 237 } else 238 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 239 } 240 241 242 /** 243 * {@inheritDoc} 244 */ 245 @Override 246 public Class<?>[] getParameterTypes() { 247 return parameterTypes.clone(); 248 } 249 250 /** 251 * {@inheritDoc} 252 * @since 1.8 253 */ 254 public int getParameterCount() { return parameterTypes.length; } 255 256 /** 257 * {@inheritDoc} 258 * @throws GenericSignatureFormatError {@inheritDoc} 259 * @throws TypeNotPresentException {@inheritDoc} 260 * @throws MalformedParameterizedTypeException {@inheritDoc} 261 * @since 1.5 262 */ 263 @Override 264 public Type[] getGenericParameterTypes() { 265 return super.getGenericParameterTypes(); 266 } 267 268 /** 269 * {@inheritDoc} 270 */ 271 @Override 272 public Class<?>[] getExceptionTypes() { 273 return exceptionTypes.clone(); 274 } 275 276 277 /** 278 * {@inheritDoc} 279 * @throws GenericSignatureFormatError {@inheritDoc} 280 * @throws TypeNotPresentException {@inheritDoc} 281 * @throws MalformedParameterizedTypeException {@inheritDoc} 282 * @since 1.5 283 */ 284 @Override 285 public Type[] getGenericExceptionTypes() { 286 return super.getGenericExceptionTypes(); 287 } 288 289 /** 290 * Compares this {@code Constructor} against the specified object. 291 * Returns true if the objects are the same. Two {@code Constructor} objects are 292 * the same if they were declared by the same class and have the 293 * same formal parameter types. 294 */ 295 public boolean equals(Object obj) { 296 if (obj != null && obj instanceof Constructor) { 297 Constructor<?> other = (Constructor<?>)obj; 298 if (getDeclaringClass() == other.getDeclaringClass()) { 299 return equalParamTypes(parameterTypes, other.parameterTypes); 300 } 301 } 302 return false; 303 } 304 305 /** 306 * Returns a hashcode for this {@code Constructor}. The hashcode is 307 * the same as the hashcode for the underlying constructor's 308 * declaring class name. 309 */ 310 public int hashCode() { 311 return getDeclaringClass().getName().hashCode(); 312 } 313 314 /** 315 * Returns a string describing this {@code Constructor}. The string is 316 * formatted as the constructor access modifiers, if any, 317 * followed by the fully-qualified name of the declaring class, 318 * followed by a parenthesized, comma-separated list of the 319 * constructor's formal parameter types. For example: 320 * <pre>{@code 321 * public java.util.Hashtable(int,float) 322 * }</pre> 323 * 324 * <p>The only possible modifiers for constructors are the access 325 * modifiers {@code public}, {@code protected} or 326 * {@code private}. Only one of these may appear, or none if the 327 * constructor has default (package) access. 328 * 329 * @return a string describing this {@code Constructor} 330 * @jls 8.8.3 Constructor Modifiers 331 * @jls 8.9.2 Enum Body Declarations 332 */ 333 public String toString() { 334 return sharedToString(Modifier.constructorModifiers(), 335 false, 336 parameterTypes, 337 exceptionTypes); 338 } 339 340 @Override 341 void specificToStringHeader(StringBuilder sb) { 342 sb.append(getDeclaringClass().getTypeName()); 343 } 344 345 /** 346 * Returns a string describing this {@code Constructor}, 347 * including type parameters. The string is formatted as the 348 * constructor access modifiers, if any, followed by an 349 * angle-bracketed comma separated list of the constructor's type 350 * parameters, if any, followed by the fully-qualified name of the 351 * declaring class, followed by a parenthesized, comma-separated 352 * list of the constructor's generic formal parameter types. 353 * 354 * If this constructor was declared to take a variable number of 355 * arguments, instead of denoting the last parameter as 356 * "<code><i>Type</i>[]</code>", it is denoted as 357 * "<code><i>Type</i>...</code>". 358 * 359 * A space is used to separate access modifiers from one another 360 * and from the type parameters or return type. If there are no 361 * type parameters, the type parameter list is elided; if the type 362 * parameter list is present, a space separates the list from the 363 * class name. If the constructor is declared to throw 364 * exceptions, the parameter list is followed by a space, followed 365 * by the word "{@code throws}" followed by a 366 * comma-separated list of the thrown exception types. 367 * 368 * <p>The only possible modifiers for constructors are the access 369 * modifiers {@code public}, {@code protected} or 370 * {@code private}. Only one of these may appear, or none if the 371 * constructor has default (package) access. 372 * 373 * @return a string describing this {@code Constructor}, 374 * include type parameters 375 * 376 * @since 1.5 377 * @jls 8.8.3 Constructor Modifiers 378 * @jls 8.9.2 Enum Body Declarations 379 */ 380 @Override 381 public String toGenericString() { 382 return sharedToGenericString(Modifier.constructorModifiers(), false); 383 } 384 385 @Override 386 void specificToGenericStringHeader(StringBuilder sb) { 387 specificToStringHeader(sb); 388 } 389 390 /** 391 * Uses the constructor represented by this {@code Constructor} object to 392 * create and initialize a new instance of the constructor's 393 * declaring class, with the specified initialization parameters. 394 * Individual parameters are automatically unwrapped to match 395 * primitive formal parameters, and both primitive and reference 396 * parameters are subject to method invocation conversions as necessary. 397 * 398 * <p>If the number of formal parameters required by the underlying constructor 399 * is 0, the supplied {@code initargs} array may be of length 0 or null. 400 * 401 * <p>If the constructor's declaring class is an inner class in a 402 * non-static context, the first argument to the constructor needs 403 * to be the enclosing instance; see section 15.9.3 of 404 * <cite>The Java™ Language Specification</cite>. 405 * 406 * <p>If the required access and argument checks succeed and the 407 * instantiation will proceed, the constructor's declaring class 408 * is initialized if it has not already been initialized. 409 * 410 * <p>If the constructor completes normally, returns the newly 411 * created and initialized instance. 412 * 413 * @param initargs array of objects to be passed as arguments to 414 * the constructor call; values of primitive types are wrapped in 415 * a wrapper object of the appropriate type (e.g. a {@code float} 416 * in a {@link java.lang.Float Float}) 417 * 418 * @return a new object created by calling the constructor 419 * this object represents 420 * 421 * @exception IllegalAccessException if this {@code Constructor} object 422 * is enforcing Java language access control and the underlying 423 * constructor is inaccessible. 424 * @exception IllegalArgumentException if the number of actual 425 * and formal parameters differ; if an unwrapping 426 * conversion for primitive arguments fails; or if, 427 * after possible unwrapping, a parameter value 428 * cannot be converted to the corresponding formal 429 * parameter type by a method invocation conversion; if 430 * this constructor pertains to an enum type. 431 * @exception InstantiationException if the class that declares the 432 * underlying constructor represents an abstract class. 433 * @exception InvocationTargetException if the underlying constructor 434 * throws an exception. 435 * @exception ExceptionInInitializerError if the initialization provoked 436 * by this method fails. 437 */ 438 @CallerSensitive 439 @ForceInline // to ensure Reflection.getCallerClass optimization 440 public T newInstance(Object ... initargs) 441 throws InstantiationException, IllegalAccessException, 442 IllegalArgumentException, InvocationTargetException 443 { 444 if (!override) { 445 Class<?> caller = Reflection.getCallerClass(); 446 checkAccess(caller, clazz, null, modifiers); 447 } 448 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 449 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 450 ConstructorAccessor ca = constructorAccessor; // read volatile 451 if (ca == null) { 452 ca = acquireConstructorAccessor(); 453 } 454 @SuppressWarnings("unchecked") 455 T inst = (T) ca.newInstance(initargs); 456 return inst; 457 } 458 459 /** 460 * {@inheritDoc} 461 * @since 1.5 462 */ 463 @Override 464 public boolean isVarArgs() { 465 return super.isVarArgs(); 466 } 467 468 /** 469 * {@inheritDoc} 470 * @jls 13.1 The Form of a Binary 471 * @since 1.5 472 */ 473 @Override 474 public boolean isSynthetic() { 475 return super.isSynthetic(); 476 } 477 478 // NOTE that there is no synchronization used here. It is correct 479 // (though not efficient) to generate more than one 480 // ConstructorAccessor for a given Constructor. However, avoiding 481 // synchronization will probably make the implementation more 482 // scalable. 483 private ConstructorAccessor acquireConstructorAccessor() { 484 // First check to see if one has been created yet, and take it 485 // if so. 486 ConstructorAccessor tmp = null; 487 if (root != null) tmp = root.getConstructorAccessor(); 488 if (tmp != null) { 489 constructorAccessor = tmp; 490 } else { 491 // Otherwise fabricate one and propagate it up to the root 492 tmp = reflectionFactory.newConstructorAccessor(this); 493 setConstructorAccessor(tmp); 494 } 495 496 return tmp; 497 } 498 499 // Returns ConstructorAccessor for this Constructor object, not 500 // looking up the chain to the root 501 ConstructorAccessor getConstructorAccessor() { 502 return constructorAccessor; 503 } 504 505 // Sets the ConstructorAccessor for this Constructor object and 506 // (recursively) its root 507 void setConstructorAccessor(ConstructorAccessor accessor) { 508 constructorAccessor = accessor; 509 // Propagate up 510 if (root != null) { 511 root.setConstructorAccessor(accessor); 512 } 513 } 514 515 int getSlot() { 516 return slot; 517 } 518 519 String getSignature() { 520 return signature; 521 } 522 523 byte[] getRawAnnotations() { 524 return annotations; 525 } 526 527 byte[] getRawParameterAnnotations() { 528 return parameterAnnotations; 529 } 530 531 532 /** 533 * {@inheritDoc} 534 * @throws NullPointerException {@inheritDoc} 535 * @since 1.5 536 */ 537 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 538 return super.getAnnotation(annotationClass); 539 } 540 541 /** 542 * {@inheritDoc} 543 * @since 1.5 544 */ 545 public Annotation[] getDeclaredAnnotations() { 546 return super.getDeclaredAnnotations(); 547 } 548 549 /** 550 * {@inheritDoc} 551 * @since 1.5 552 */ 553 @Override 554 public Annotation[][] getParameterAnnotations() { 555 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 556 } 557 558 @Override 559 void handleParameterNumberMismatch(int resultLength, int numParameters) { 560 Class<?> declaringClass = getDeclaringClass(); 561 if (declaringClass.isEnum() || 562 declaringClass.isAnonymousClass() || 563 declaringClass.isLocalClass() ) 564 return ; // Can't do reliable parameter counting 565 else { 566 if (!declaringClass.isMemberClass() || // top-level 567 // Check for the enclosing instance parameter for 568 // non-static member classes 569 (declaringClass.isMemberClass() && 570 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 571 resultLength + 1 != numParameters) ) { 572 throw new AnnotationFormatError( 573 "Parameter annotations don't match number of parameters"); 574 } 575 } 576 } 577 578 /** 579 * {@inheritDoc} 580 * @since 1.8 581 */ 582 @Override 583 public AnnotatedType getAnnotatedReturnType() { 584 return getAnnotatedReturnType0(getDeclaringClass()); 585 } 586 587 /** 588 * {@inheritDoc} 589 * @since 1.8 590 */ 591 @Override 592 public AnnotatedType getAnnotatedReceiverType() { 593 Class<?> thisDeclClass = getDeclaringClass(); 594 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 595 596 if (enclosingClass == null) { 597 // A Constructor for a top-level class 598 return null; 599 } 600 601 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 602 if (outerDeclaringClass == null) { 603 // A constructor for a local or anonymous class 604 return null; 605 } 606 607 // Either static nested or inner class 608 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 609 // static nested 610 return null; 611 } 612 613 // A Constructor for an inner class 614 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 615 SharedSecrets.getJavaLangAccess(). 616 getConstantPool(thisDeclClass), 617 this, 618 thisDeclClass, 619 enclosingClass, 620 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 621 } 622 }