1 /* 2 * Copyright (c) 1996, 2018, 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.access.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 import java.util.StringJoiner; 42 43 /** 44 * {@code Constructor} provides information about, and access to, a single 45 * constructor for a class. 46 * 47 * <p>{@code Constructor} permits widening conversions to occur when matching the 48 * actual parameters to newInstance() with the underlying 49 * constructor's formal parameters, but throws an 50 * {@code IllegalArgumentException} if a narrowing conversion would occur. 51 * 52 * @param <T> the class in which the constructor is declared 53 * 54 * @see Member 55 * @see java.lang.Class 56 * @see java.lang.Class#getConstructors() 57 * @see java.lang.Class#getConstructor(Class[]) 58 * @see java.lang.Class#getDeclaredConstructors() 59 * 60 * @author Kenneth Russell 61 * @author Nakul Saraiya 62 * @since 1.1 63 */ 64 public final class Constructor<T> extends Executable { 65 private Class<T> clazz; 66 private int slot; 67 private Class<?>[] parameterTypes; 68 private Class<?>[] exceptionTypes; 69 private int modifiers; 70 // Generics and annotations support 71 private transient String signature; 72 // generic info repository; lazily initialized 73 private transient ConstructorRepository genericInfo; 74 private byte[] annotations; 75 private byte[] parameterAnnotations; 76 77 // Generics infrastructure 78 // Accessor for factory 79 private GenericsFactory getFactory() { 80 // create scope and factory 81 return CoreReflectionFactory.make(this, ConstructorScope.make(this)); 82 } 83 84 // Accessor for generic info repository 85 @Override 86 ConstructorRepository getGenericInfo() { 87 // lazily initialize repository if necessary 88 if (genericInfo == null) { 89 // create and cache generic info repository 90 genericInfo = 91 ConstructorRepository.make(getSignature(), 92 getFactory()); 93 } 94 return genericInfo; //return cached repository 95 } 96 97 private volatile ConstructorAccessor constructorAccessor; 98 // For sharing of ConstructorAccessors. This branching structure 99 // is currently only two levels deep (i.e., one root Constructor 100 // and potentially many Constructor objects pointing to it.) 101 // 102 // If this branching structure would ever contain cycles, deadlocks can 103 // occur in annotation code. 104 private Constructor<T> root; 105 106 @Override 107 Constructor<T> 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 /** 163 * {@inheritDoc} 164 * 165 * <p> A {@code SecurityException} is also thrown if this object is a 166 * {@code Constructor} object for the class {@code Class} and {@code flag} 167 * is true. </p> 168 * 169 * @param flag {@inheritDoc} 170 * 171 * @throws InaccessibleObjectException {@inheritDoc} 172 * @throws SecurityException if the request is denied by the security manager 173 * or this is a constructor for {@code java.lang.Class} 174 * 175 * @spec JPMS 176 */ 177 @Override 178 @CallerSensitive 179 public void setAccessible(boolean flag) { 180 AccessibleObject.checkPermission(); 181 182 if (flag) { 183 checkCanSetAccessible(Reflection.getCallerClass()); 184 } 185 setAccessible0(flag); 186 } 187 188 @Override 189 void checkCanSetAccessible(Class<?> caller) { 190 checkCanSetAccessible(caller, clazz); 191 if (clazz == Class.class) { 192 // can we change this to InaccessibleObjectException? 193 throw new SecurityException("Cannot make a java.lang.Class" 194 + " constructor accessible"); 195 } 196 } 197 198 @Override 199 boolean hasGenericInformation() { 200 return (getSignature() != null); 201 } 202 203 @Override 204 byte[] getAnnotationBytes() { 205 return annotations; 206 } 207 208 /** 209 * Returns the {@code Class} object representing the class that 210 * declares the constructor represented by this object. 211 */ 212 @Override 213 public Class<T> getDeclaringClass() { 214 return clazz; 215 } 216 217 /** 218 * Returns the name of this constructor, as a string. This is 219 * the binary name of the constructor's declaring class. 220 */ 221 @Override 222 public String getName() { 223 return getDeclaringClass().getName(); 224 } 225 226 /** 227 * {@inheritDoc} 228 */ 229 @Override 230 public int getModifiers() { 231 return modifiers; 232 } 233 234 /** 235 * {@inheritDoc} 236 * @throws GenericSignatureFormatError {@inheritDoc} 237 * @since 1.5 238 */ 239 @Override 240 @SuppressWarnings({"rawtypes", "unchecked"}) 241 public TypeVariable<Constructor<T>>[] getTypeParameters() { 242 if (getSignature() != null) { 243 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 244 } else 245 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 246 } 247 248 249 @Override 250 Class<?>[] getSharedParameterTypes() { 251 return parameterTypes; 252 } 253 254 @Override 255 Class<?>[] getSharedExceptionTypes() { 256 return exceptionTypes; 257 } 258 259 /** 260 * {@inheritDoc} 261 */ 262 @Override 263 public Class<?>[] getParameterTypes() { 264 return parameterTypes.clone(); 265 } 266 267 /** 268 * {@inheritDoc} 269 * @since 1.8 270 */ 271 public int getParameterCount() { return parameterTypes.length; } 272 273 /** 274 * {@inheritDoc} 275 * @throws GenericSignatureFormatError {@inheritDoc} 276 * @throws TypeNotPresentException {@inheritDoc} 277 * @throws MalformedParameterizedTypeException {@inheritDoc} 278 * @since 1.5 279 */ 280 @Override 281 public Type[] getGenericParameterTypes() { 282 return super.getGenericParameterTypes(); 283 } 284 285 /** 286 * {@inheritDoc} 287 */ 288 @Override 289 public Class<?>[] getExceptionTypes() { 290 return exceptionTypes.clone(); 291 } 292 293 294 /** 295 * {@inheritDoc} 296 * @throws GenericSignatureFormatError {@inheritDoc} 297 * @throws TypeNotPresentException {@inheritDoc} 298 * @throws MalformedParameterizedTypeException {@inheritDoc} 299 * @since 1.5 300 */ 301 @Override 302 public Type[] getGenericExceptionTypes() { 303 return super.getGenericExceptionTypes(); 304 } 305 306 /** 307 * Compares this {@code Constructor} against the specified object. 308 * Returns true if the objects are the same. Two {@code Constructor} objects are 309 * the same if they were declared by the same class and have the 310 * same formal parameter types. 311 */ 312 public boolean equals(Object obj) { 313 if (obj != null && obj instanceof Constructor) { 314 Constructor<?> other = (Constructor<?>)obj; 315 if (getDeclaringClass() == other.getDeclaringClass()) { 316 return equalParamTypes(parameterTypes, other.parameterTypes); 317 } 318 } 319 return false; 320 } 321 322 /** 323 * Returns a hashcode for this {@code Constructor}. The hashcode is 324 * the same as the hashcode for the underlying constructor's 325 * declaring class name. 326 */ 327 public int hashCode() { 328 return getDeclaringClass().getName().hashCode(); 329 } 330 331 /** 332 * Returns a string describing this {@code Constructor}. The string is 333 * formatted as the constructor access modifiers, if any, 334 * followed by the fully-qualified name of the declaring class, 335 * followed by a parenthesized, comma-separated list of the 336 * constructor's formal parameter types. For example: 337 * <pre>{@code 338 * public java.util.Hashtable(int,float) 339 * }</pre> 340 * 341 * <p>If the constructor is declared to throw exceptions, the 342 * parameter list is followed by a space, followed by the word 343 * "{@code throws}" followed by a comma-separated list of the 344 * thrown exception types. 345 * 346 * <p>The only possible modifiers for constructors are the access 347 * modifiers {@code public}, {@code protected} or 348 * {@code private}. Only one of these may appear, or none if the 349 * constructor has default (package) access. 350 * 351 * @return a string describing this {@code Constructor} 352 * @jls 8.8.3 Constructor Modifiers 353 * @jls 8.9.2 Enum Body Declarations 354 */ 355 public String toString() { 356 return sharedToString(Modifier.constructorModifiers(), 357 false, 358 parameterTypes, 359 exceptionTypes); 360 } 361 362 @Override 363 void specificToStringHeader(StringBuilder sb) { 364 sb.append(getDeclaringClass().getTypeName()); 365 } 366 367 @Override 368 String toShortString() { 369 StringBuilder sb = new StringBuilder("constructor "); 370 sb.append(getDeclaringClass().getTypeName()); 371 sb.append('('); 372 StringJoiner sj = new StringJoiner(","); 373 for (Class<?> parameterType : getParameterTypes()) { 374 sj.add(parameterType.getTypeName()); 375 } 376 sb.append(sj); 377 sb.append(')'); 378 return sb.toString(); 379 } 380 381 /** 382 * Returns a string describing this {@code Constructor}, 383 * including type parameters. The string is formatted as the 384 * constructor access modifiers, if any, followed by an 385 * angle-bracketed comma separated list of the constructor's type 386 * parameters, if any, including informative bounds of the 387 * type parameters, if any, followed by the fully-qualified name of the 388 * declaring class, followed by a parenthesized, comma-separated 389 * list of the constructor's generic formal parameter types. 390 * 391 * If this constructor was declared to take a variable number of 392 * arguments, instead of denoting the last parameter as 393 * "<code><i>Type</i>[]</code>", it is denoted as 394 * "<code><i>Type</i>...</code>". 395 * 396 * A space is used to separate access modifiers from one another 397 * and from the type parameters or class name. If there are no 398 * type parameters, the type parameter list is elided; if the type 399 * parameter list is present, a space separates the list from the 400 * class name. If the constructor is declared to throw 401 * exceptions, the parameter list is followed by a space, followed 402 * by the word "{@code throws}" followed by a 403 * comma-separated list of the generic thrown exception types. 404 * 405 * <p>The only possible modifiers for constructors are the access 406 * modifiers {@code public}, {@code protected} or 407 * {@code private}. Only one of these may appear, or none if the 408 * constructor has default (package) access. 409 * 410 * @return a string describing this {@code Constructor}, 411 * include type parameters 412 * 413 * @since 1.5 414 * @jls 8.8.3 Constructor Modifiers 415 * @jls 8.9.2 Enum Body Declarations 416 */ 417 @Override 418 public String toGenericString() { 419 return sharedToGenericString(Modifier.constructorModifiers(), false); 420 } 421 422 @Override 423 void specificToGenericStringHeader(StringBuilder sb) { 424 specificToStringHeader(sb); 425 } 426 427 /** 428 * Uses the constructor represented by this {@code Constructor} object to 429 * create and initialize a new instance of the constructor's 430 * declaring class, with the specified initialization parameters. 431 * Individual parameters are automatically unwrapped to match 432 * primitive formal parameters, and both primitive and reference 433 * parameters are subject to method invocation conversions as necessary. 434 * 435 * <p>If the number of formal parameters required by the underlying constructor 436 * is 0, the supplied {@code initargs} array may be of length 0 or null. 437 * 438 * <p>If the constructor's declaring class is an inner class in a 439 * non-static context, the first argument to the constructor needs 440 * to be the enclosing instance; see section 15.9.3 of 441 * <cite>The Java™ Language Specification</cite>. 442 * 443 * <p>If the required access and argument checks succeed and the 444 * instantiation will proceed, the constructor's declaring class 445 * is initialized if it has not already been initialized. 446 * 447 * <p>If the constructor completes normally, returns the newly 448 * created and initialized instance. 449 * 450 * @param initargs array of objects to be passed as arguments to 451 * the constructor call; values of primitive types are wrapped in 452 * a wrapper object of the appropriate type (e.g. a {@code float} 453 * in a {@link java.lang.Float Float}) 454 * 455 * @return a new object created by calling the constructor 456 * this object represents 457 * 458 * @exception IllegalAccessException if this {@code Constructor} object 459 * is enforcing Java language access control and the underlying 460 * constructor is inaccessible. 461 * @exception IllegalArgumentException if the number of actual 462 * and formal parameters differ; if an unwrapping 463 * conversion for primitive arguments fails; or if, 464 * after possible unwrapping, a parameter value 465 * cannot be converted to the corresponding formal 466 * parameter type by a method invocation conversion; if 467 * this constructor pertains to an enum type. 468 * @exception InstantiationException if the class that declares the 469 * underlying constructor represents an abstract class. 470 * @exception InvocationTargetException if the underlying constructor 471 * throws an exception. 472 * @exception ExceptionInInitializerError if the initialization provoked 473 * by this method fails. 474 */ 475 @CallerSensitive 476 @ForceInline // to ensure Reflection.getCallerClass optimization 477 public T newInstance(Object ... initargs) 478 throws InstantiationException, IllegalAccessException, 479 IllegalArgumentException, InvocationTargetException 480 { 481 Class<?> caller = override ? null : Reflection.getCallerClass(); 482 return newInstanceWithCaller(initargs, !override, caller); 483 } 484 485 /* package-private */ 486 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller) 487 throws InstantiationException, IllegalAccessException, 488 InvocationTargetException 489 { 490 if (checkAccess) 491 checkAccess(caller, clazz, clazz, modifiers); 492 493 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 494 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 495 496 ConstructorAccessor ca = constructorAccessor; // read volatile 497 if (ca == null) { 498 ca = acquireConstructorAccessor(); 499 } 500 @SuppressWarnings("unchecked") 501 T inst = (T) ca.newInstance(args); 502 return inst; 503 } 504 505 /** 506 * {@inheritDoc} 507 * @since 1.5 508 */ 509 @Override 510 public boolean isVarArgs() { 511 return super.isVarArgs(); 512 } 513 514 /** 515 * {@inheritDoc} 516 * @jls 13.1 The Form of a Binary 517 * @since 1.5 518 */ 519 @Override 520 public boolean isSynthetic() { 521 return super.isSynthetic(); 522 } 523 524 // NOTE that there is no synchronization used here. It is correct 525 // (though not efficient) to generate more than one 526 // ConstructorAccessor for a given Constructor. However, avoiding 527 // synchronization will probably make the implementation more 528 // scalable. 529 private ConstructorAccessor acquireConstructorAccessor() { 530 // First check to see if one has been created yet, and take it 531 // if so. 532 ConstructorAccessor tmp = null; 533 if (root != null) tmp = root.getConstructorAccessor(); 534 if (tmp != null) { 535 constructorAccessor = tmp; 536 } else { 537 // Otherwise fabricate one and propagate it up to the root 538 tmp = reflectionFactory.newConstructorAccessor(this); 539 setConstructorAccessor(tmp); 540 } 541 542 return tmp; 543 } 544 545 // Returns ConstructorAccessor for this Constructor object, not 546 // looking up the chain to the root 547 ConstructorAccessor getConstructorAccessor() { 548 return constructorAccessor; 549 } 550 551 // Sets the ConstructorAccessor for this Constructor object and 552 // (recursively) its root 553 void setConstructorAccessor(ConstructorAccessor accessor) { 554 constructorAccessor = accessor; 555 // Propagate up 556 if (root != null) { 557 root.setConstructorAccessor(accessor); 558 } 559 } 560 561 int getSlot() { 562 return slot; 563 } 564 565 String getSignature() { 566 return signature; 567 } 568 569 byte[] getRawAnnotations() { 570 return annotations; 571 } 572 573 byte[] getRawParameterAnnotations() { 574 return parameterAnnotations; 575 } 576 577 578 /** 579 * {@inheritDoc} 580 * @throws NullPointerException {@inheritDoc} 581 * @since 1.5 582 */ 583 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 584 return super.getAnnotation(annotationClass); 585 } 586 587 /** 588 * {@inheritDoc} 589 * @since 1.5 590 */ 591 public Annotation[] getDeclaredAnnotations() { 592 return super.getDeclaredAnnotations(); 593 } 594 595 /** 596 * {@inheritDoc} 597 * @since 1.5 598 */ 599 @Override 600 public Annotation[][] getParameterAnnotations() { 601 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 602 } 603 604 @Override 605 boolean handleParameterNumberMismatch(int resultLength, int numParameters) { 606 Class<?> declaringClass = getDeclaringClass(); 607 if (declaringClass.isEnum() || 608 declaringClass.isAnonymousClass() || 609 declaringClass.isLocalClass() ) 610 return false; // Can't do reliable parameter counting 611 else { 612 if (declaringClass.isMemberClass() && 613 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 614 resultLength + 1 == numParameters) { 615 return true; 616 } else { 617 throw new AnnotationFormatError( 618 "Parameter annotations don't match number of parameters"); 619 } 620 } 621 } 622 623 /** 624 * {@inheritDoc} 625 * @since 1.8 626 */ 627 @Override 628 public AnnotatedType getAnnotatedReturnType() { 629 return getAnnotatedReturnType0(getDeclaringClass()); 630 } 631 632 /** 633 * {@inheritDoc} 634 * @since 1.8 635 */ 636 @Override 637 public AnnotatedType getAnnotatedReceiverType() { 638 Class<?> thisDeclClass = getDeclaringClass(); 639 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 640 641 if (enclosingClass == null) { 642 // A Constructor for a top-level class 643 return null; 644 } 645 646 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 647 if (outerDeclaringClass == null) { 648 // A constructor for a local or anonymous class 649 return null; 650 } 651 652 // Either static nested or inner class 653 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 654 // static nested 655 return null; 656 } 657 658 // A Constructor for an inner class 659 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 660 SharedSecrets.getJavaLangAccess(). 661 getConstantPool(thisDeclClass), 662 this, 663 thisDeclClass, 664 enclosingClass, 665 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 666 } 667 }