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 if (clazz.isValue()) { 184 throw new InaccessibleObjectException( 185 "Unable to make an inline class constructor \"" + this + "\" accessible"); 186 } 187 checkCanSetAccessible(Reflection.getCallerClass()); 188 } 189 setAccessible0(flag); 190 } 191 192 @Override 193 void checkCanSetAccessible(Class<?> caller) { 194 checkCanSetAccessible(caller, clazz); 195 if (clazz == Class.class) { 196 // can we change this to InaccessibleObjectException? 197 throw new SecurityException("Cannot make a java.lang.Class" 198 + " constructor accessible"); 199 } 200 } 201 202 @Override 203 boolean hasGenericInformation() { 204 return (getSignature() != null); 205 } 206 207 @Override 208 byte[] getAnnotationBytes() { 209 return annotations; 210 } 211 212 /** 213 * Returns the {@code Class} object representing 214 * {@linkplain Class#asBoxType() the box type} of the class that 215 * declares the constructor represented by this object. 216 */ 217 @Override 218 public Class<T> getDeclaringClass() { 219 return clazz; 220 } 221 222 /** 223 * Returns the name of this constructor, as a string. This is 224 * the binary name of the constructor's declaring class. 225 */ 226 @Override 227 public String getName() { 228 return getDeclaringClass().getName(); 229 } 230 231 /** 232 * {@inheritDoc} 233 */ 234 @Override 235 public int getModifiers() { 236 return modifiers; 237 } 238 239 /** 240 * {@inheritDoc} 241 * @throws GenericSignatureFormatError {@inheritDoc} 242 * @since 1.5 243 */ 244 @Override 245 @SuppressWarnings({"rawtypes", "unchecked"}) 246 public TypeVariable<Constructor<T>>[] getTypeParameters() { 247 if (getSignature() != null) { 248 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 249 } else 250 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 251 } 252 253 254 @Override 255 Class<?>[] getSharedParameterTypes() { 256 return parameterTypes; 257 } 258 259 @Override 260 Class<?>[] getSharedExceptionTypes() { 261 return exceptionTypes; 262 } 263 264 /** 265 * {@inheritDoc} 266 */ 267 @Override 268 public Class<?>[] getParameterTypes() { 269 return parameterTypes.clone(); 270 } 271 272 /** 273 * {@inheritDoc} 274 * @since 1.8 275 */ 276 public int getParameterCount() { return parameterTypes.length; } 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[] getGenericParameterTypes() { 287 return super.getGenericParameterTypes(); 288 } 289 290 /** 291 * {@inheritDoc} 292 */ 293 @Override 294 public Class<?>[] getExceptionTypes() { 295 return exceptionTypes.clone(); 296 } 297 298 299 /** 300 * {@inheritDoc} 301 * @throws GenericSignatureFormatError {@inheritDoc} 302 * @throws TypeNotPresentException {@inheritDoc} 303 * @throws MalformedParameterizedTypeException {@inheritDoc} 304 * @since 1.5 305 */ 306 @Override 307 public Type[] getGenericExceptionTypes() { 308 return super.getGenericExceptionTypes(); 309 } 310 311 /** 312 * Compares this {@code Constructor} against the specified object. 313 * Returns true if the objects are the same. Two {@code Constructor} objects are 314 * the same if they were declared by the same class and have the 315 * same formal parameter types. 316 */ 317 public boolean equals(Object obj) { 318 if (obj != null && obj instanceof Constructor) { 319 Constructor<?> other = (Constructor<?>)obj; 320 if (getDeclaringClass() == other.getDeclaringClass()) { 321 return equalParamTypes(parameterTypes, other.parameterTypes); 322 } 323 } 324 return false; 325 } 326 327 /** 328 * Returns a hashcode for this {@code Constructor}. The hashcode is 329 * the same as the hashcode for the underlying constructor's 330 * declaring class name. 331 */ 332 public int hashCode() { 333 return getDeclaringClass().getName().hashCode(); 334 } 335 336 /** 337 * Returns a string describing this {@code Constructor}. The string is 338 * formatted as the constructor access modifiers, if any, 339 * followed by the fully-qualified name of the declaring class, 340 * followed by a parenthesized, comma-separated list of the 341 * constructor's formal parameter types. For example: 342 * <pre>{@code 343 * public java.util.Hashtable(int,float) 344 * }</pre> 345 * 346 * <p>If the constructor is declared to throw exceptions, the 347 * parameter list is followed by a space, followed by the word 348 * "{@code throws}" followed by a comma-separated list of the 349 * thrown exception types. 350 * 351 * <p>The only possible modifiers for constructors are the access 352 * modifiers {@code public}, {@code protected} or 353 * {@code private}. Only one of these may appear, or none if the 354 * constructor has default (package) access. 355 * 356 * @return a string describing this {@code Constructor} 357 * @jls 8.8.3 Constructor Modifiers 358 * @jls 8.9.2 Enum Body Declarations 359 */ 360 public String toString() { 361 return sharedToString(Modifier.constructorModifiers(), 362 false, 363 parameterTypes, 364 exceptionTypes); 365 } 366 367 @Override 368 void specificToStringHeader(StringBuilder sb) { 369 sb.append(getDeclaringClass().getTypeName()); 370 } 371 372 @Override 373 String toShortString() { 374 StringBuilder sb = new StringBuilder("constructor "); 375 sb.append(getDeclaringClass().getTypeName()); 376 sb.append('('); 377 StringJoiner sj = new StringJoiner(","); 378 for (Class<?> parameterType : getParameterTypes()) { 379 sj.add(parameterType.getTypeName()); 380 } 381 sb.append(sj); 382 sb.append(')'); 383 return sb.toString(); 384 } 385 386 /** 387 * Returns a string describing this {@code Constructor}, 388 * including type parameters. The string is formatted as the 389 * constructor access modifiers, if any, followed by an 390 * angle-bracketed comma separated list of the constructor's type 391 * parameters, if any, including informative bounds of the 392 * type parameters, if any, followed by the fully-qualified name of the 393 * declaring class, followed by a parenthesized, comma-separated 394 * list of the constructor's generic formal parameter types. 395 * 396 * If this constructor was declared to take a variable number of 397 * arguments, instead of denoting the last parameter as 398 * "<code><i>Type</i>[]</code>", it is denoted as 399 * "<code><i>Type</i>...</code>". 400 * 401 * A space is used to separate access modifiers from one another 402 * and from the type parameters or class name. If there are no 403 * type parameters, the type parameter list is elided; if the type 404 * parameter list is present, a space separates the list from the 405 * class name. If the constructor is declared to throw 406 * exceptions, the parameter list is followed by a space, followed 407 * by the word "{@code throws}" followed by a 408 * comma-separated list of the generic thrown exception types. 409 * 410 * <p>The only possible modifiers for constructors are the access 411 * modifiers {@code public}, {@code protected} or 412 * {@code private}. Only one of these may appear, or none if the 413 * constructor has default (package) access. 414 * 415 * @return a string describing this {@code Constructor}, 416 * include type parameters 417 * 418 * @since 1.5 419 * @jls 8.8.3 Constructor Modifiers 420 * @jls 8.9.2 Enum Body Declarations 421 */ 422 @Override 423 public String toGenericString() { 424 return sharedToGenericString(Modifier.constructorModifiers(), false); 425 } 426 427 @Override 428 void specificToGenericStringHeader(StringBuilder sb) { 429 specificToStringHeader(sb); 430 } 431 432 /** 433 * Uses the constructor represented by this {@code Constructor} object to 434 * create and initialize a new instance of the constructor's 435 * declaring class, with the specified initialization parameters. 436 * Individual parameters are automatically unwrapped to match 437 * primitive formal parameters, and both primitive and reference 438 * parameters are subject to method invocation conversions as necessary. 439 * 440 * <p>If the number of formal parameters required by the underlying constructor 441 * is 0, the supplied {@code initargs} array may be of length 0 or null. 442 * 443 * <p>If the constructor's declaring class is an inner class in a 444 * non-static context, the first argument to the constructor needs 445 * to be the enclosing instance; see section 15.9.3 of 446 * <cite>The Java™ Language Specification</cite>. 447 * 448 * <p>If the required access and argument checks succeed and the 449 * instantiation will proceed, the constructor's declaring class 450 * is initialized if it has not already been initialized. 451 * 452 * <p>If the constructor completes normally, returns the newly 453 * created and initialized instance. 454 * 455 * @param initargs array of objects to be passed as arguments to 456 * the constructor call; values of primitive types are wrapped in 457 * a wrapper object of the appropriate type (e.g. a {@code float} 458 * in a {@link java.lang.Float Float}) 459 * 460 * @return a new object created by calling the constructor 461 * this object represents 462 * 463 * @exception IllegalAccessException if this {@code Constructor} object 464 * is enforcing Java language access control and the underlying 465 * constructor is inaccessible. 466 * @exception IllegalArgumentException if the number of actual 467 * and formal parameters differ; if an unwrapping 468 * conversion for primitive arguments fails; or if, 469 * after possible unwrapping, a parameter value 470 * cannot be converted to the corresponding formal 471 * parameter type by a method invocation conversion; if 472 * this constructor pertains to an enum type. 473 * @exception InstantiationException if the class that declares the 474 * underlying constructor represents an abstract class. 475 * @exception InvocationTargetException if the underlying constructor 476 * throws an exception. 477 * @exception ExceptionInInitializerError if the initialization provoked 478 * by this method fails. 479 */ 480 @CallerSensitive 481 @ForceInline // to ensure Reflection.getCallerClass optimization 482 public T newInstance(Object ... initargs) 483 throws InstantiationException, IllegalAccessException, 484 IllegalArgumentException, InvocationTargetException 485 { 486 if (clazz.isValue()) { 487 throw new IllegalAccessException( 488 "cannot create new instance of an inline class " + clazz.getName()); 489 } 490 Class<?> caller = override ? null : Reflection.getCallerClass(); 491 return newInstanceWithCaller(initargs, !override, caller); 492 } 493 494 /* package-private */ 495 T newInstanceWithCaller(Object[] args, boolean checkAccess, Class<?> caller) 496 throws InstantiationException, IllegalAccessException, 497 InvocationTargetException 498 { 499 if (checkAccess) 500 checkAccess(caller, clazz, clazz, modifiers); 501 502 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 503 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 504 505 ConstructorAccessor ca = constructorAccessor; // read volatile 506 if (ca == null) { 507 ca = acquireConstructorAccessor(); 508 } 509 @SuppressWarnings("unchecked") 510 T inst = (T) ca.newInstance(args); 511 return inst; 512 } 513 514 /** 515 * {@inheritDoc} 516 * @since 1.5 517 */ 518 @Override 519 public boolean isVarArgs() { 520 return super.isVarArgs(); 521 } 522 523 /** 524 * {@inheritDoc} 525 * @jls 13.1 The Form of a Binary 526 * @since 1.5 527 */ 528 @Override 529 public boolean isSynthetic() { 530 return super.isSynthetic(); 531 } 532 533 // NOTE that there is no synchronization used here. It is correct 534 // (though not efficient) to generate more than one 535 // ConstructorAccessor for a given Constructor. However, avoiding 536 // synchronization will probably make the implementation more 537 // scalable. 538 private ConstructorAccessor acquireConstructorAccessor() { 539 // First check to see if one has been created yet, and take it 540 // if so. 541 ConstructorAccessor tmp = null; 542 if (root != null) tmp = root.getConstructorAccessor(); 543 if (tmp != null) { 544 constructorAccessor = tmp; 545 } else { 546 // Otherwise fabricate one and propagate it up to the root 547 tmp = reflectionFactory.newConstructorAccessor(this); 548 setConstructorAccessor(tmp); 549 } 550 551 return tmp; 552 } 553 554 // Returns ConstructorAccessor for this Constructor object, not 555 // looking up the chain to the root 556 ConstructorAccessor getConstructorAccessor() { 557 return constructorAccessor; 558 } 559 560 // Sets the ConstructorAccessor for this Constructor object and 561 // (recursively) its root 562 void setConstructorAccessor(ConstructorAccessor accessor) { 563 constructorAccessor = accessor; 564 // Propagate up 565 if (root != null) { 566 root.setConstructorAccessor(accessor); 567 } 568 } 569 570 int getSlot() { 571 return slot; 572 } 573 574 String getSignature() { 575 return signature; 576 } 577 578 byte[] getRawAnnotations() { 579 return annotations; 580 } 581 582 byte[] getRawParameterAnnotations() { 583 return parameterAnnotations; 584 } 585 586 587 /** 588 * {@inheritDoc} 589 * @throws NullPointerException {@inheritDoc} 590 * @since 1.5 591 */ 592 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 593 return super.getAnnotation(annotationClass); 594 } 595 596 /** 597 * {@inheritDoc} 598 * @since 1.5 599 */ 600 public Annotation[] getDeclaredAnnotations() { 601 return super.getDeclaredAnnotations(); 602 } 603 604 /** 605 * {@inheritDoc} 606 * @since 1.5 607 */ 608 @Override 609 public Annotation[][] getParameterAnnotations() { 610 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 611 } 612 613 @Override 614 boolean handleParameterNumberMismatch(int resultLength, int numParameters) { 615 Class<?> declaringClass = getDeclaringClass(); 616 if (declaringClass.isEnum() || 617 declaringClass.isAnonymousClass() || 618 declaringClass.isLocalClass() ) 619 return false; // Can't do reliable parameter counting 620 else { 621 if (declaringClass.isMemberClass() && 622 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 623 resultLength + 1 == numParameters) { 624 return true; 625 } else { 626 throw new AnnotationFormatError( 627 "Parameter annotations don't match number of parameters"); 628 } 629 } 630 } 631 632 /** 633 * {@inheritDoc} 634 * @since 1.8 635 */ 636 @Override 637 public AnnotatedType getAnnotatedReturnType() { 638 return getAnnotatedReturnType0(getDeclaringClass()); 639 } 640 641 /** 642 * {@inheritDoc} 643 * @since 1.8 644 */ 645 @Override 646 public AnnotatedType getAnnotatedReceiverType() { 647 Class<?> thisDeclClass = getDeclaringClass(); 648 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 649 650 if (enclosingClass == null) { 651 // A Constructor for a top-level class 652 return null; 653 } 654 655 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 656 if (outerDeclaringClass == null) { 657 // A constructor for a local or anonymous class 658 return null; 659 } 660 661 // Either static nested or inner class 662 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 663 // static nested 664 return null; 665 } 666 667 // A Constructor for an inner class 668 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 669 SharedSecrets.getJavaLangAccess(). 670 getConstantPool(thisDeclClass), 671 this, 672 thisDeclClass, 673 enclosingClass, 674 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 675 } 676 }