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 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, followed by the fully-qualified name of the 386 * declaring class, followed by a parenthesized, comma-separated 387 * list of the constructor's generic formal parameter types. 388 * 389 * If this constructor was declared to take a variable number of 390 * arguments, instead of denoting the last parameter as 391 * "<code><i>Type</i>[]</code>", it is denoted as 392 * "<code><i>Type</i>...</code>". 393 * 394 * A space is used to separate access modifiers from one another 395 * and from the type parameters or class name. If there are no 396 * type parameters, the type parameter list is elided; if the type 397 * parameter list is present, a space separates the list from the 398 * class name. If the constructor is declared to throw 399 * exceptions, the parameter list is followed by a space, followed 400 * by the word "{@code throws}" followed by a 401 * comma-separated list of the generic thrown exception types. 402 * 403 * <p>The only possible modifiers for constructors are the access 404 * modifiers {@code public}, {@code protected} or 405 * {@code private}. Only one of these may appear, or none if the 406 * constructor has default (package) access. 407 * 408 * @return a string describing this {@code Constructor}, 409 * include type parameters 410 * 411 * @since 1.5 412 * @jls 8.8.3 Constructor Modifiers 413 * @jls 8.9.2 Enum Body Declarations 414 */ 415 @Override 416 public String toGenericString() { 417 return sharedToGenericString(Modifier.constructorModifiers(), false); 418 } 419 420 @Override 421 void specificToGenericStringHeader(StringBuilder sb) { 422 specificToStringHeader(sb); 423 } 424 425 /** 426 * Uses the constructor represented by this {@code Constructor} object to 427 * create and initialize a new instance of the constructor's 428 * declaring class, with the specified initialization parameters. 429 * Individual parameters are automatically unwrapped to match 430 * primitive formal parameters, and both primitive and reference 431 * parameters are subject to method invocation conversions as necessary. 432 * 433 * <p>If the number of formal parameters required by the underlying constructor 434 * is 0, the supplied {@code initargs} array may be of length 0 or null. 435 * 436 * <p>If the constructor's declaring class is an inner class in a 437 * non-static context, the first argument to the constructor needs 438 * to be the enclosing instance; see section 15.9.3 of 439 * <cite>The Java™ Language Specification</cite>. 440 * 441 * <p>If the required access and argument checks succeed and the 442 * instantiation will proceed, the constructor's declaring class 443 * is initialized if it has not already been initialized. 444 * 445 * <p>If the constructor completes normally, returns the newly 446 * created and initialized instance. 447 * 448 * @param initargs array of objects to be passed as arguments to 449 * the constructor call; values of primitive types are wrapped in 450 * a wrapper object of the appropriate type (e.g. a {@code float} 451 * in a {@link java.lang.Float Float}) 452 * 453 * @return a new object created by calling the constructor 454 * this object represents 455 * 456 * @exception IllegalAccessException if this {@code Constructor} object 457 * is enforcing Java language access control and the underlying 458 * constructor is inaccessible. 459 * @exception IllegalArgumentException if the number of actual 460 * and formal parameters differ; if an unwrapping 461 * conversion for primitive arguments fails; or if, 462 * after possible unwrapping, a parameter value 463 * cannot be converted to the corresponding formal 464 * parameter type by a method invocation conversion; if 465 * this constructor pertains to an enum type. 466 * @exception InstantiationException if the class that declares the 467 * underlying constructor represents an abstract class. 468 * @exception InvocationTargetException if the underlying constructor 469 * throws an exception. 470 * @exception ExceptionInInitializerError if the initialization provoked 471 * by this method fails. 472 */ 473 @CallerSensitive 474 @ForceInline // to ensure Reflection.getCallerClass optimization 475 public T newInstance(Object ... initargs) 476 throws InstantiationException, IllegalAccessException, 477 IllegalArgumentException, InvocationTargetException 478 { 479 if (!override) { 480 Class<?> caller = Reflection.getCallerClass(); 481 checkAccess(caller, clazz, clazz, modifiers); 482 } 483 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 484 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 485 ConstructorAccessor ca = constructorAccessor; // read volatile 486 if (ca == null) { 487 ca = acquireConstructorAccessor(); 488 } 489 @SuppressWarnings("unchecked") 490 T inst = (T) ca.newInstance(initargs); 491 return inst; 492 } 493 494 /** 495 * {@inheritDoc} 496 * @since 1.5 497 */ 498 @Override 499 public boolean isVarArgs() { 500 return super.isVarArgs(); 501 } 502 503 /** 504 * {@inheritDoc} 505 * @jls 13.1 The Form of a Binary 506 * @since 1.5 507 */ 508 @Override 509 public boolean isSynthetic() { 510 return super.isSynthetic(); 511 } 512 513 // NOTE that there is no synchronization used here. It is correct 514 // (though not efficient) to generate more than one 515 // ConstructorAccessor for a given Constructor. However, avoiding 516 // synchronization will probably make the implementation more 517 // scalable. 518 private ConstructorAccessor acquireConstructorAccessor() { 519 // First check to see if one has been created yet, and take it 520 // if so. 521 ConstructorAccessor tmp = null; 522 if (root != null) tmp = root.getConstructorAccessor(); 523 if (tmp != null) { 524 constructorAccessor = tmp; 525 } else { 526 // Otherwise fabricate one and propagate it up to the root 527 tmp = reflectionFactory.newConstructorAccessor(this); 528 setConstructorAccessor(tmp); 529 } 530 531 return tmp; 532 } 533 534 // Returns ConstructorAccessor for this Constructor object, not 535 // looking up the chain to the root 536 ConstructorAccessor getConstructorAccessor() { 537 return constructorAccessor; 538 } 539 540 // Sets the ConstructorAccessor for this Constructor object and 541 // (recursively) its root 542 void setConstructorAccessor(ConstructorAccessor accessor) { 543 constructorAccessor = accessor; 544 // Propagate up 545 if (root != null) { 546 root.setConstructorAccessor(accessor); 547 } 548 } 549 550 int getSlot() { 551 return slot; 552 } 553 554 String getSignature() { 555 return signature; 556 } 557 558 byte[] getRawAnnotations() { 559 return annotations; 560 } 561 562 byte[] getRawParameterAnnotations() { 563 return parameterAnnotations; 564 } 565 566 567 /** 568 * {@inheritDoc} 569 * @throws NullPointerException {@inheritDoc} 570 * @since 1.5 571 */ 572 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 573 return super.getAnnotation(annotationClass); 574 } 575 576 /** 577 * {@inheritDoc} 578 * @since 1.5 579 */ 580 public Annotation[] getDeclaredAnnotations() { 581 return super.getDeclaredAnnotations(); 582 } 583 584 /** 585 * {@inheritDoc} 586 * @since 1.5 587 */ 588 @Override 589 public Annotation[][] getParameterAnnotations() { 590 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 591 } 592 593 @Override 594 boolean handleParameterNumberMismatch(int resultLength, int numParameters) { 595 Class<?> declaringClass = getDeclaringClass(); 596 if (declaringClass.isEnum() || 597 declaringClass.isAnonymousClass() || 598 declaringClass.isLocalClass() ) 599 return false; // Can't do reliable parameter counting 600 else { 601 if (declaringClass.isMemberClass() && 602 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 603 resultLength + 1 == numParameters) { 604 return true; 605 } else { 606 throw new AnnotationFormatError( 607 "Parameter annotations don't match number of parameters"); 608 } 609 } 610 } 611 612 /** 613 * {@inheritDoc} 614 * @since 1.8 615 */ 616 @Override 617 public AnnotatedType getAnnotatedReturnType() { 618 return getAnnotatedReturnType0(getDeclaringClass()); 619 } 620 621 /** 622 * {@inheritDoc} 623 * @since 1.8 624 */ 625 @Override 626 public AnnotatedType getAnnotatedReceiverType() { 627 Class<?> thisDeclClass = getDeclaringClass(); 628 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 629 630 if (enclosingClass == null) { 631 // A Constructor for a top-level class 632 return null; 633 } 634 635 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 636 if (outerDeclaringClass == null) { 637 // A constructor for a local or anonymous class 638 return null; 639 } 640 641 // Either static nested or inner class 642 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 643 // static nested 644 return null; 645 } 646 647 // A Constructor for an inner class 648 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 649 SharedSecrets.getJavaLangAccess(). 650 getConstantPool(thisDeclClass), 651 this, 652 thisDeclClass, 653 enclosingClass, 654 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 655 } 656 }