1 /* 2 * Copyright (c) 1996, 2017, 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 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 /** 107 * Used by Excecutable for annotation sharing. 108 */ 109 @Override 110 Executable getRoot() { 111 return root; 112 } 113 114 /** 115 * Package-private constructor used by ReflectAccess to enable 116 * instantiation of these objects in Java code from the java.lang 117 * package via sun.reflect.LangReflectAccess. 118 */ 119 Constructor(Class<T> declaringClass, 120 Class<?>[] parameterTypes, 121 Class<?>[] checkedExceptions, 122 int modifiers, 123 int slot, 124 String signature, 125 byte[] annotations, 126 byte[] parameterAnnotations) { 127 this.clazz = declaringClass; 128 this.parameterTypes = parameterTypes; 129 this.exceptionTypes = checkedExceptions; 130 this.modifiers = modifiers; 131 this.slot = slot; 132 this.signature = signature; 133 this.annotations = annotations; 134 this.parameterAnnotations = parameterAnnotations; 135 } 136 137 /** 138 * Package-private routine (exposed to java.lang.Class via 139 * ReflectAccess) which returns a copy of this Constructor. The copy's 140 * "root" field points to this Constructor. 141 */ 142 Constructor<T> copy() { 143 // This routine enables sharing of ConstructorAccessor objects 144 // among Constructor objects which refer to the same underlying 145 // method in the VM. (All of this contortion is only necessary 146 // because of the "accessibility" bit in AccessibleObject, 147 // which implicitly requires that new java.lang.reflect 148 // objects be fabricated for each reflective call on Class 149 // objects.) 150 if (this.root != null) 151 throw new IllegalArgumentException("Can not copy a non-root Constructor"); 152 153 Constructor<T> res = new Constructor<>(clazz, 154 parameterTypes, 155 exceptionTypes, modifiers, slot, 156 signature, 157 annotations, 158 parameterAnnotations); 159 res.root = this; 160 // Might as well eagerly propagate this if already present 161 res.constructorAccessor = constructorAccessor; 162 return res; 163 } 164 165 /** 166 * {@inheritDoc} 167 * 168 * <p> A {@code SecurityException} is also thrown if this object is a 169 * {@code Constructor} object for the class {@code Class} and {@code flag} 170 * is true. </p> 171 * 172 * @param flag {@inheritDoc} 173 * 174 * @throws InaccessibleObjectException {@inheritDoc} 175 * @throws SecurityException if the request is denied by the security manager 176 * or this is a constructor for {@code java.lang.Class} 177 * 178 * @spec JPMS 179 */ 180 @Override 181 @CallerSensitive 182 public void setAccessible(boolean flag) { 183 AccessibleObject.checkPermission(); 184 185 if (clazz.isValue()) { 186 throw new InaccessibleObjectException( 187 "Unable to make a value class constructor \"" + this + "\" accessible"); 188 } 189 190 if (flag) { 191 checkCanSetAccessible(Reflection.getCallerClass()); 192 } 193 setAccessible0(flag); 194 } 195 196 @Override 197 void checkCanSetAccessible(Class<?> caller) { 198 checkCanSetAccessible(caller, clazz); 199 if (clazz == Class.class) { 200 // can we change this to InaccessibleObjectException? 201 throw new SecurityException("Cannot make a java.lang.Class" 202 + " constructor accessible"); 203 } 204 } 205 206 @Override 207 boolean hasGenericInformation() { 208 return (getSignature() != null); 209 } 210 211 @Override 212 byte[] getAnnotationBytes() { 213 return annotations; 214 } 215 216 /** 217 * Returns the {@code Class} object representing the class that 218 * declares the constructor represented by this object. 219 */ 220 @Override 221 public Class<T> getDeclaringClass() { 222 return clazz; 223 } 224 225 /** 226 * Returns the name of this constructor, as a string. This is 227 * the binary name of the constructor's declaring class. 228 */ 229 @Override 230 public String getName() { 231 return getDeclaringClass().getName(); 232 } 233 234 /** 235 * {@inheritDoc} 236 */ 237 @Override 238 public int getModifiers() { 239 return modifiers; 240 } 241 242 /** 243 * {@inheritDoc} 244 * @throws GenericSignatureFormatError {@inheritDoc} 245 * @since 1.5 246 */ 247 @Override 248 @SuppressWarnings({"rawtypes", "unchecked"}) 249 public TypeVariable<Constructor<T>>[] getTypeParameters() { 250 if (getSignature() != null) { 251 return (TypeVariable<Constructor<T>>[])getGenericInfo().getTypeParameters(); 252 } else 253 return (TypeVariable<Constructor<T>>[])new TypeVariable[0]; 254 } 255 256 257 @Override 258 Class<?>[] getSharedParameterTypes() { 259 return parameterTypes; 260 } 261 262 /** 263 * {@inheritDoc} 264 */ 265 @Override 266 public Class<?>[] getParameterTypes() { 267 return parameterTypes.clone(); 268 } 269 270 /** 271 * {@inheritDoc} 272 * @since 1.8 273 */ 274 public int getParameterCount() { return parameterTypes.length; } 275 276 /** 277 * {@inheritDoc} 278 * @throws GenericSignatureFormatError {@inheritDoc} 279 * @throws TypeNotPresentException {@inheritDoc} 280 * @throws MalformedParameterizedTypeException {@inheritDoc} 281 * @since 1.5 282 */ 283 @Override 284 public Type[] getGenericParameterTypes() { 285 return super.getGenericParameterTypes(); 286 } 287 288 /** 289 * {@inheritDoc} 290 */ 291 @Override 292 public Class<?>[] getExceptionTypes() { 293 return exceptionTypes.clone(); 294 } 295 296 297 /** 298 * {@inheritDoc} 299 * @throws GenericSignatureFormatError {@inheritDoc} 300 * @throws TypeNotPresentException {@inheritDoc} 301 * @throws MalformedParameterizedTypeException {@inheritDoc} 302 * @since 1.5 303 */ 304 @Override 305 public Type[] getGenericExceptionTypes() { 306 return super.getGenericExceptionTypes(); 307 } 308 309 /** 310 * Compares this {@code Constructor} against the specified object. 311 * Returns true if the objects are the same. Two {@code Constructor} objects are 312 * the same if they were declared by the same class and have the 313 * same formal parameter types. 314 */ 315 public boolean equals(Object obj) { 316 if (obj != null && obj instanceof Constructor) { 317 Constructor<?> other = (Constructor<?>)obj; 318 if (getDeclaringClass() == other.getDeclaringClass()) { 319 return equalParamTypes(parameterTypes, other.parameterTypes); 320 } 321 } 322 return false; 323 } 324 325 /** 326 * Returns a hashcode for this {@code Constructor}. The hashcode is 327 * the same as the hashcode for the underlying constructor's 328 * declaring class name. 329 */ 330 public int hashCode() { 331 return getDeclaringClass().getName().hashCode(); 332 } 333 334 /** 335 * Returns a string describing this {@code Constructor}. The string is 336 * formatted as the constructor access modifiers, if any, 337 * followed by the fully-qualified name of the declaring class, 338 * followed by a parenthesized, comma-separated list of the 339 * constructor's formal parameter types. For example: 340 * <pre>{@code 341 * public java.util.Hashtable(int,float) 342 * }</pre> 343 * 344 * <p>If the constructor is declared to throw exceptions, the 345 * parameter list is followed by a space, followed by the word 346 * "{@code throws}" followed by a comma-separated list of the 347 * thrown exception types. 348 * 349 * <p>The only possible modifiers for constructors are the access 350 * modifiers {@code public}, {@code protected} or 351 * {@code private}. Only one of these may appear, or none if the 352 * constructor has default (package) access. 353 * 354 * @return a string describing this {@code Constructor} 355 * @jls 8.8.3 Constructor Modifiers 356 * @jls 8.9.2 Enum Body Declarations 357 */ 358 public String toString() { 359 return sharedToString(Modifier.constructorModifiers(), 360 false, 361 parameterTypes, 362 exceptionTypes); 363 } 364 365 @Override 366 void specificToStringHeader(StringBuilder sb) { 367 sb.append(getDeclaringClass().getTypeName()); 368 } 369 370 @Override 371 String toShortString() { 372 StringBuilder sb = new StringBuilder("constructor "); 373 sb.append(getDeclaringClass().getTypeName()); 374 sb.append('('); 375 StringJoiner sj = new StringJoiner(","); 376 for (Class<?> parameterType : getParameterTypes()) { 377 sj.add(parameterType.getTypeName()); 378 } 379 sb.append(sj); 380 sb.append(')'); 381 return sb.toString(); 382 } 383 384 /** 385 * Returns a string describing this {@code Constructor}, 386 * including type parameters. The string is formatted as the 387 * constructor access modifiers, if any, followed by an 388 * angle-bracketed comma separated list of the constructor's type 389 * parameters, if any, followed by the fully-qualified name of the 390 * declaring class, followed by a parenthesized, comma-separated 391 * list of the constructor's generic formal parameter types. 392 * 393 * If this constructor was declared to take a variable number of 394 * arguments, instead of denoting the last parameter as 395 * "<code><i>Type</i>[]</code>", it is denoted as 396 * "<code><i>Type</i>...</code>". 397 * 398 * A space is used to separate access modifiers from one another 399 * and from the type parameters or class name. If there are no 400 * type parameters, the type parameter list is elided; if the type 401 * parameter list is present, a space separates the list from the 402 * class name. If the constructor is declared to throw 403 * exceptions, the parameter list is followed by a space, followed 404 * by the word "{@code throws}" followed by a 405 * comma-separated list of the generic thrown exception types. 406 * 407 * <p>The only possible modifiers for constructors are the access 408 * modifiers {@code public}, {@code protected} or 409 * {@code private}. Only one of these may appear, or none if the 410 * constructor has default (package) access. 411 * 412 * @return a string describing this {@code Constructor}, 413 * include type parameters 414 * 415 * @since 1.5 416 * @jls 8.8.3 Constructor Modifiers 417 * @jls 8.9.2 Enum Body Declarations 418 */ 419 @Override 420 public String toGenericString() { 421 return sharedToGenericString(Modifier.constructorModifiers(), false); 422 } 423 424 @Override 425 void specificToGenericStringHeader(StringBuilder sb) { 426 specificToStringHeader(sb); 427 } 428 429 /** 430 * Uses the constructor represented by this {@code Constructor} object to 431 * create and initialize a new instance of the constructor's 432 * declaring class, with the specified initialization parameters. 433 * Individual parameters are automatically unwrapped to match 434 * primitive formal parameters, and both primitive and reference 435 * parameters are subject to method invocation conversions as necessary. 436 * 437 * <p>If the number of formal parameters required by the underlying constructor 438 * is 0, the supplied {@code initargs} array may be of length 0 or null. 439 * 440 * <p>If the constructor's declaring class is an inner class in a 441 * non-static context, the first argument to the constructor needs 442 * to be the enclosing instance; see section 15.9.3 of 443 * <cite>The Java™ Language Specification</cite>. 444 * 445 * <p>If the required access and argument checks succeed and the 446 * instantiation will proceed, the constructor's declaring class 447 * is initialized if it has not already been initialized. 448 * 449 * <p>If the constructor completes normally, returns the newly 450 * created and initialized instance. 451 * 452 * @param initargs array of objects to be passed as arguments to 453 * the constructor call; values of primitive types are wrapped in 454 * a wrapper object of the appropriate type (e.g. a {@code float} 455 * in a {@link java.lang.Float Float}) 456 * 457 * @return a new object created by calling the constructor 458 * this object represents 459 * 460 * @exception IllegalAccessException if this {@code Constructor} object 461 * is enforcing Java language access control and the underlying 462 * constructor is inaccessible. 463 * @exception IllegalArgumentException if the number of actual 464 * and formal parameters differ; if an unwrapping 465 * conversion for primitive arguments fails; or if, 466 * after possible unwrapping, a parameter value 467 * cannot be converted to the corresponding formal 468 * parameter type by a method invocation conversion; if 469 * this constructor pertains to an enum type. 470 * @exception InstantiationException if the class that declares the 471 * underlying constructor represents an abstract class. 472 * @exception InvocationTargetException if the underlying constructor 473 * throws an exception. 474 * @exception ExceptionInInitializerError if the initialization provoked 475 * by this method fails. 476 */ 477 @CallerSensitive 478 @ForceInline // to ensure Reflection.getCallerClass optimization 479 public T newInstance(Object ... initargs) 480 throws InstantiationException, IllegalAccessException, 481 IllegalArgumentException, InvocationTargetException 482 { 483 if (clazz.isValue()) { 484 throw new IllegalAccessException( 485 "cannot create new instance of value class " + clazz.getName()); 486 } 487 488 if (!override) { 489 Class<?> caller = Reflection.getCallerClass(); 490 checkAccess(caller, clazz, clazz, modifiers); 491 } 492 if ((clazz.getModifiers() & Modifier.ENUM) != 0) 493 throw new IllegalArgumentException("Cannot reflectively create enum objects"); 494 ConstructorAccessor ca = constructorAccessor; // read volatile 495 if (ca == null) { 496 ca = acquireConstructorAccessor(); 497 } 498 @SuppressWarnings("unchecked") 499 T inst = (T) ca.newInstance(initargs); 500 return inst; 501 } 502 503 /** 504 * {@inheritDoc} 505 * @since 1.5 506 */ 507 @Override 508 public boolean isVarArgs() { 509 return super.isVarArgs(); 510 } 511 512 /** 513 * {@inheritDoc} 514 * @jls 13.1 The Form of a Binary 515 * @since 1.5 516 */ 517 @Override 518 public boolean isSynthetic() { 519 return super.isSynthetic(); 520 } 521 522 // NOTE that there is no synchronization used here. It is correct 523 // (though not efficient) to generate more than one 524 // ConstructorAccessor for a given Constructor. However, avoiding 525 // synchronization will probably make the implementation more 526 // scalable. 527 private ConstructorAccessor acquireConstructorAccessor() { 528 // First check to see if one has been created yet, and take it 529 // if so. 530 ConstructorAccessor tmp = null; 531 if (root != null) tmp = root.getConstructorAccessor(); 532 if (tmp != null) { 533 constructorAccessor = tmp; 534 } else { 535 // Otherwise fabricate one and propagate it up to the root 536 tmp = reflectionFactory.newConstructorAccessor(this); 537 setConstructorAccessor(tmp); 538 } 539 540 return tmp; 541 } 542 543 // Returns ConstructorAccessor for this Constructor object, not 544 // looking up the chain to the root 545 ConstructorAccessor getConstructorAccessor() { 546 return constructorAccessor; 547 } 548 549 // Sets the ConstructorAccessor for this Constructor object and 550 // (recursively) its root 551 void setConstructorAccessor(ConstructorAccessor accessor) { 552 constructorAccessor = accessor; 553 // Propagate up 554 if (root != null) { 555 root.setConstructorAccessor(accessor); 556 } 557 } 558 559 int getSlot() { 560 return slot; 561 } 562 563 String getSignature() { 564 return signature; 565 } 566 567 byte[] getRawAnnotations() { 568 return annotations; 569 } 570 571 byte[] getRawParameterAnnotations() { 572 return parameterAnnotations; 573 } 574 575 576 /** 577 * {@inheritDoc} 578 * @throws NullPointerException {@inheritDoc} 579 * @since 1.5 580 */ 581 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 582 return super.getAnnotation(annotationClass); 583 } 584 585 /** 586 * {@inheritDoc} 587 * @since 1.5 588 */ 589 public Annotation[] getDeclaredAnnotations() { 590 return super.getDeclaredAnnotations(); 591 } 592 593 /** 594 * {@inheritDoc} 595 * @since 1.5 596 */ 597 @Override 598 public Annotation[][] getParameterAnnotations() { 599 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 600 } 601 602 @Override 603 boolean handleParameterNumberMismatch(int resultLength, int numParameters) { 604 Class<?> declaringClass = getDeclaringClass(); 605 if (declaringClass.isEnum() || 606 declaringClass.isAnonymousClass() || 607 declaringClass.isLocalClass() ) 608 return false; // Can't do reliable parameter counting 609 else { 610 if (declaringClass.isMemberClass() && 611 ((declaringClass.getModifiers() & Modifier.STATIC) == 0) && 612 resultLength + 1 == numParameters) { 613 return true; 614 } else { 615 throw new AnnotationFormatError( 616 "Parameter annotations don't match number of parameters"); 617 } 618 } 619 } 620 621 /** 622 * {@inheritDoc} 623 * @since 1.8 624 */ 625 @Override 626 public AnnotatedType getAnnotatedReturnType() { 627 return getAnnotatedReturnType0(getDeclaringClass()); 628 } 629 630 /** 631 * {@inheritDoc} 632 * @since 1.8 633 */ 634 @Override 635 public AnnotatedType getAnnotatedReceiverType() { 636 Class<?> thisDeclClass = getDeclaringClass(); 637 Class<?> enclosingClass = thisDeclClass.getEnclosingClass(); 638 639 if (enclosingClass == null) { 640 // A Constructor for a top-level class 641 return null; 642 } 643 644 Class<?> outerDeclaringClass = thisDeclClass.getDeclaringClass(); 645 if (outerDeclaringClass == null) { 646 // A constructor for a local or anonymous class 647 return null; 648 } 649 650 // Either static nested or inner class 651 if (Modifier.isStatic(thisDeclClass.getModifiers())) { 652 // static nested 653 return null; 654 } 655 656 // A Constructor for an inner class 657 return TypeAnnotationParser.buildAnnotatedType(getTypeAnnotationBytes0(), 658 SharedSecrets.getJavaLangAccess(). 659 getConstantPool(thisDeclClass), 660 this, 661 thisDeclClass, 662 enclosingClass, 663 TypeAnnotation.TypeAnnotationTarget.METHOD_RECEIVER); 664 } 665 }