1 /* 2 * Copyright (c) 1996, 2020, 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 jdk.internal.access.JavaLangReflectAccess. 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 if (flag) { 182 checkCanSetAccessible(Reflection.getCallerClass()); 183 } 184 setAccessible0(flag); 185 } 186 187 @Override 188 void checkCanSetAccessible(Class<?> caller) { 189 checkCanSetAccessible(caller, clazz); 190 if (clazz == Class.class) { 191 // can we change this to InaccessibleObjectException? 192 throw new SecurityException("Cannot make a java.lang.Class" 193 + " constructor accessible"); 194 } 195 } 196 197 @Override 198 boolean hasGenericInformation() { 199 return (getSignature() != null); 200 } 201 202 @Override 203 byte[] getAnnotationBytes() { 204 return annotations; 205 } 206 207 /** 208 * Returns the {@code Class} object representing the class that 209 * declares the constructor represented by this object. 210 */ 211 @Override 212 public Class<T> getDeclaringClass() { 213 return clazz; 214 } 215 216 /** 217 * Returns the name of this constructor, as a string. This is 218 * the binary name of the constructor's declaring class. 219 */ 220 @Override 221 public String getName() { 222 return getDeclaringClass().getName(); 223 } 224 225 /** 226 * {@inheritDoc} 227 */ 228 @Override 229 public int getModifiers() { 230 return modifiers; 231 } 232 233 /** 234 * {@inheritDoc} 235 * @throws GenericSignatureFormatError {@inheritDoc} 236 * @since 1.5 237 */ 238 @Override 239 @SuppressWarnings({"rawtypes", "unchecked"}) 240 public TypeVariable<Constructor<T>>[] getTypeParameters() { 241 if (getSignature() != null) { 242 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 243 } else 244 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 245 } 246 247 248 @Override 249 Class<?>[] getSharedParameterTypes() { 250 return parameterTypes; 251 } 252 253 @Override 254 Class<?>[] getSharedExceptionTypes() { 255 return exceptionTypes; 256 } 257 258 /** 259 * {@inheritDoc} 260 */ 261 @Override 262 public Class<?>[] getParameterTypes() { 263 return parameterTypes.clone(); 264 } 265 266 /** 267 * {@inheritDoc} 268 * @since 1.8 269 */ 270 public int getParameterCount() { return parameterTypes.length; } 271 272 /** 273 * {@inheritDoc} 274 * @throws GenericSignatureFormatError {@inheritDoc} 275 * @throws TypeNotPresentException {@inheritDoc} 276 * @throws MalformedParameterizedTypeException {@inheritDoc} 277 * @since 1.5 278 */ 279 @Override 280 public Type[] getGenericParameterTypes() { 281 return super.getGenericParameterTypes(); 282 } 283 284 /** 285 * {@inheritDoc} 286 */ 287 @Override 288 public Class<?>[] getExceptionTypes() { 289 return exceptionTypes.clone(); 290 } 291 292 293 /** 294 * {@inheritDoc} 295 * @throws GenericSignatureFormatError {@inheritDoc} 296 * @throws TypeNotPresentException {@inheritDoc} 297 * @throws MalformedParameterizedTypeException {@inheritDoc} 298 * @since 1.5 299 */ 300 @Override 301 public Type[] getGenericExceptionTypes() { 302 return super.getGenericExceptionTypes(); 303 } 304 305 /** 306 * Compares this {@code Constructor} against the specified object. 307 * Returns true if the objects are the same. Two {@code Constructor} objects are 308 * the same if they were declared by the same class and have the 309 * same formal parameter types. 310 */ 311 public boolean equals(Object obj) { 312 if (obj != null && obj instanceof Constructor) { 313 Constructor<?> other = (Constructor<?>)obj; 314 if (getDeclaringClass() == other.getDeclaringClass()) { 315 return equalParamTypes(parameterTypes, other.parameterTypes); 316 } 317 } 318 return false; 319 } 320 321 /** 322 * Returns a hashcode for this {@code Constructor}. The hashcode is 323 * the same as the hashcode for the underlying constructor's 324 * declaring class name. 325 */ 326 public int hashCode() { 327 return getDeclaringClass().getName().hashCode(); 328 } 329 330 /** 331 * Returns a string describing this {@code Constructor}. The string is 332 * formatted as the constructor access modifiers, if any, 333 * followed by the fully-qualified name of the declaring class, 334 * followed by a parenthesized, comma-separated list of the 335 * constructor's formal parameter types. For example: 336 * <pre>{@code 337 * public java.util.Hashtable(int,float) 338 * }</pre> 339 * 340 * <p>If the constructor is declared to throw exceptions, the 341 * parameter list is followed by a space, followed by the word 342 * "{@code throws}" followed by a comma-separated list of the 343 * thrown exception types. 344 * 345 * <p>The only possible modifiers for constructors are the access 346 * modifiers {@code public}, {@code protected} or 347 * {@code private}. Only one of these may appear, or none if the 348 * constructor has default (package) access. 349 * 350 * @return a string describing this {@code Constructor} 351 * @jls 8.8.3 Constructor Modifiers 352 * @jls 8.9.2 Enum Body Declarations 353 */ 354 public String toString() { 355 return sharedToString(Modifier.constructorModifiers(), 356 false, 357 parameterTypes, 358 exceptionTypes); 359 } 360 361 @Override 362 void specificToStringHeader(StringBuilder sb) { 363 sb.append(getDeclaringClass().getTypeName()); 364 } 365 366 @Override 367 String toShortString() { 368 StringBuilder sb = new StringBuilder("constructor "); 369 sb.append(getDeclaringClass().getTypeName()); 370 sb.append('('); 371 StringJoiner sj = new StringJoiner(","); 372 for (Class<?> parameterType : getParameterTypes()) { 373 sj.add(parameterType.getTypeName()); 374 } 375 sb.append(sj); 376 sb.append(')'); 377 return sb.toString(); 378 } 379 380 /** 381 * Returns a string describing this {@code Constructor}, 382 * including type parameters. The string is formatted as the 383 * constructor access modifiers, if any, followed by an 384 * angle-bracketed comma separated list of the constructor's type 385 * parameters, if any, including informative bounds of the 386 * type parameters, if any, followed by the fully-qualified name of the 387 * declaring class, followed by a parenthesized, comma-separated 388 * list of the constructor's generic formal parameter types. 389 * 390 * If this constructor was declared to take a variable number of 391 * arguments, instead of denoting the last parameter as 392 * "<code><i>Type</i>[]</code>", it is denoted as 393 * "<code><i>Type</i>...</code>". 394 * 395 * A space is used to separate access modifiers from one another 396 * and from the type parameters or class name. If there are no 397 * type parameters, the type parameter list is elided; if the type 398 * parameter list is present, a space separates the list from the 399 * class name. If the constructor is declared to throw 400 * exceptions, the parameter list is followed by a space, followed 401 * by the word "{@code throws}" followed by a 402 * comma-separated list of the generic thrown exception types. 403 * 404 * <p>The only possible modifiers for constructors are the access 405 * modifiers {@code public}, {@code protected} or 406 * {@code private}. Only one of these may appear, or none if the 407 * constructor has default (package) access. 408 * 409 * @return a string describing this {@code Constructor}, 410 * include type parameters 411 * 412 * @since 1.5 413 * @jls 8.8.3 Constructor Modifiers 414 * @jls 8.9.2 Enum Body Declarations 415 */ 416 @Override 417 public String toGenericString() { 418 return sharedToGenericString(Modifier.constructorModifiers(), false); 419 } 420 421 @Override 422 void specificToGenericStringHeader(StringBuilder sb) { 423 specificToStringHeader(sb); 424 } 425 426 /** 427 * Uses the constructor represented by this {@code Constructor} object to 428 * create and initialize a new instance of the constructor's 429 * declaring class, with the specified initialization parameters. 430 * Individual parameters are automatically unwrapped to match 431 * primitive formal parameters, and both primitive and reference 432 * parameters are subject to method invocation conversions as necessary. 433 * 434 * <p>If the number of formal parameters required by the underlying constructor 435 * is 0, the supplied {@code initargs} array may be of length 0 or null. 436 * 437 * <p>If the constructor's declaring class is an inner class in a 438 * non-static context, the first argument to the constructor needs 439 * to be the enclosing instance; see section 15.9.3 of 440 * <cite>The Java™ Language Specification</cite>. 441 * 442 * <p>If the required access and argument checks succeed and the 443 * instantiation will proceed, the constructor's declaring class 444 * is initialized if it has not already been initialized. 445 * 446 * <p>If the constructor completes normally, returns the newly 447 * created and initialized instance. 448 * 449 * @param initargs array of objects to be passed as arguments to 450 * the constructor call; values of primitive types are wrapped in 451 * a wrapper object of the appropriate type (e.g. a {@code float} 452 * in a {@link java.lang.Float Float}) 453 * 454 * @return a new object created by calling the constructor 455 * this object represents 456 * 457 * @throws IllegalAccessException if this {@code Constructor} object 458 * is enforcing Java language access control and the underlying 459 * constructor is inaccessible. 460 * @throws IllegalArgumentException if the number of actual 461 * and formal parameters differ; if an unwrapping 462 * conversion for primitive arguments fails; or if, 463 * after possible unwrapping, a parameter value 464 * cannot be converted to the corresponding formal 465 * parameter type by a method invocation conversion; if 466 * this constructor pertains to an enum type. 467 * @throws InstantiationException if the class that declares the 468 * underlying constructor represents an abstract class. 469 * @throws InvocationTargetException if the underlying constructor 470 * throws an exception. 471 * @throws ExceptionInInitializerError if the initialization provoked 472 * by this method fails. 473 */ 474 @CallerSensitive 475 @ForceInline // to ensure Reflection.getCallerClass optimization 476 public T newInstance(Object ... initargs) 477 throws InstantiationException, IllegalAccessException, 478 IllegalArgumentException, InvocationTargetException 479 { 480 Class<?> caller = override ? null : Reflection.getCallerClass(); 481 return newInstanceWithCaller(initargs, !override, caller); 482 } 483 484 /* package-private */ 485 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller) 486 throws InstantiationException, IllegalAccessException, 487 InvocationTargetException 488 { 489 if (checkAccess) 490 checkAccess(caller, clazz, clazz, modifiers); 491 492 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 493 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 494 495 ConstructorAccessor ca = constructorAccessor; // read volatile 496 if (ca == null) { 497 ca = acquireConstructorAccessor(); 498 } 499 @SuppressWarnings("unchecked") 500 T inst = (T) ca.newInstance(args); 501 return inst; 502 } 503 504 /** 505 * {@inheritDoc} 506 * @since 1.5 507 */ 508 @Override 509 public boolean isVarArgs() { 510 return super.isVarArgs(); 511 } 512 513 /** 514 * {@inheritDoc} 515 * @jls 13.1 The Form of a Binary 516 * @since 1.5 517 */ 518 @Override 519 public boolean isSynthetic() { 520 return super.isSynthetic(); 521 } 522 523 // NOTE that there is no synchronization used here. It is correct 524 // (though not efficient) to generate more than one 525 // ConstructorAccessor for a given Constructor. However, avoiding 526 // synchronization will probably make the implementation more 527 // scalable. 528 private ConstructorAccessor acquireConstructorAccessor() { 529 // First check to see if one has been created yet, and take it 530 // if so. 531 ConstructorAccessor tmp = null; 532 if (root != null) tmp = root.getConstructorAccessor(); 533 if (tmp != null) { 534 constructorAccessor = tmp; 535 } else { 536 // Otherwise fabricate one and propagate it up to the root 537 tmp = reflectionFactory.newConstructorAccessor(this); 538 setConstructorAccessor(tmp); 539 } 540 541 return tmp; 542 } 543 544 // Returns ConstructorAccessor for this Constructor object, not 545 // looking up the chain to the root 546 ConstructorAccessor getConstructorAccessor() { 547 return constructorAccessor; 548 } 549 550 // Sets the ConstructorAccessor for this Constructor object and 551 // (recursively) its root 552 void setConstructorAccessor(ConstructorAccessor accessor) { 553 constructorAccessor = accessor; 554 // Propagate up 555 if (root != null) { 556 root.setConstructorAccessor(accessor); 557 } 558 } 559 560 int getSlot() { 561 return slot; 562 } 563 564 String getSignature() { 565 return signature; 566 } 567 568 byte[] getRawAnnotations() { 569 return annotations; 570 } 571 572 byte[] getRawParameterAnnotations() { 573 return parameterAnnotations; 574 } 575 576 577 /** 578 * {@inheritDoc} 579 * 580 * @throws NullPointerException {@inheritDoc} 581 * @since 1.5 582 */ 583 @Override 584 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 585 return super.getAnnotation(annotationClass); 586 } 587 588 /** 589 * {@inheritDoc} 590 * @since 1.5 591 */ 592 @Override 593 public Annotation[] getDeclaredAnnotations() { 594 return super.getDeclaredAnnotations(); 595 } 596 597 /** 598 * {@inheritDoc} 599 * @since 1.5 600 */ 601 @Override 602 public Annotation[][] getParameterAnnotations() { 603 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 604 } 605 606 @Override 607 boolean handleParameterNumberMismatch(int resultLength, int numParameters) { 608 Class<?> declaringClass = getDeclaringClass(); 609 if (declaringClass.isEnum() || 610 declaringClass.isAnonymousClass() || 611 declaringClass.isLocalClass() ) 612 return false; // Can't do reliable parameter counting 613 else { 614 if (declaringClass.isMemberClass() && 615 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 616 resultLength + 1 == numParameters) { 617 return true; 618 } else { 619 throw new AnnotationFormatError( 620 "Parameter annotations don't match number of parameters"); 621 } 622 } 623 } 624 625 /** 626 * {@inheritDoc} 627 * @since 1.8 628 */ 629 @Override 630 public AnnotatedType getAnnotatedReturnType() { 631 return getAnnotatedReturnType0(getDeclaringClass()); 632 } 633 634 /** 635 * {@inheritDoc} 636 * @since 1.8 637 */ 638 @Override 639 public AnnotatedType getAnnotatedReceiverType() { 640 Class<?> thisDeclClass = getDeclaringClass(); 641 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 642 643 if (enclosingClass == null) { 644 // A Constructor for a top-level class 645 return null; 646 } 647 648 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 649 if (outerDeclaringClass == null) { 650 // A constructor for a local or anonymous class 651 return null; 652 } 653 654 // Either static nested or inner class 655 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 656 // static nested 657 return null; 658 } 659 660 // A Constructor for an inner class 661 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 662 SharedSecrets.getJavaLangAccess(). 663 getConstantPool(thisDeclClass), 664 this, 665 thisDeclClass, 666 enclosingClass, 667 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 668 } 669 }