1 /* 2 * Copyright (c) 1996, 2012, 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 sun.reflect.MethodAccessor; 29 import sun.reflect.Reflection; 30 import sun.reflect.generics.repository.MethodRepository; 31 import sun.reflect.generics.factory.CoreReflectionFactory; 32 import sun.reflect.generics.factory.GenericsFactory; 33 import sun.reflect.generics.scope.MethodScope; 34 import sun.reflect.annotation.AnnotationType; 35 import sun.reflect.annotation.AnnotationParser; 36 import java.lang.annotation.Annotation; 37 import java.lang.annotation.AnnotationFormatError; 38 import java.nio.ByteBuffer; 39 40 /** 41 * A {@code Method} provides information about, and access to, a single method 42 * on a class or interface. The reflected method may be a class method 43 * or an instance method (including an abstract method). 44 * 45 * <p>A {@code Method} permits widening conversions to occur when matching the 46 * actual parameters to invoke with the underlying method's formal 47 * parameters, but it throws an {@code IllegalArgumentException} if a 48 * narrowing conversion would occur. 49 * 50 * @see Member 51 * @see java.lang.Class 52 * @see java.lang.Class#getMethods() 53 * @see java.lang.Class#getMethod(String, Class[]) 54 * @see java.lang.Class#getDeclaredMethods() 55 * @see java.lang.Class#getDeclaredMethod(String, Class[]) 56 * 57 * @author Kenneth Russell 58 * @author Nakul Saraiya 59 */ 60 public final class Method extends Executable { 61 private Class<?> clazz; 62 private int slot; 63 // This is guaranteed to be interned by the VM in the 1.4 64 // reflection implementation 65 private String name; 66 private Class<?> returnType; 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 MethodRepository genericInfo; 74 private byte[] annotations; 75 private byte[] parameterAnnotations; 76 private byte[] annotationDefault; 77 private volatile MethodAccessor methodAccessor; 78 // For sharing of MethodAccessors. This branching structure is 79 // currently only two levels deep (i.e., one root Method and 80 // potentially many Method objects pointing to it.) 81 private Method root; 82 // This is set by the vm at Method creation 83 private byte[] typeAnnotations; 84 85 // Generics infrastructure 86 private String getGenericSignature() {return signature;} 87 88 // Accessor for factory 89 private GenericsFactory getFactory() { 90 // create scope and factory 91 return CoreReflectionFactory.make(this, MethodScope.make(this)); 92 } 93 94 // Accessor for generic info repository 95 @Override 96 MethodRepository getGenericInfo() { 97 // lazily initialize repository if necessary 98 if (genericInfo == null) { 99 // create and cache generic info repository 100 genericInfo = MethodRepository.make(getGenericSignature(), 101 getFactory()); 102 } 103 return genericInfo; //return cached repository 104 } 105 106 /** 107 * Package-private constructor used by ReflectAccess to enable 108 * instantiation of these objects in Java code from the java.lang 109 * package via sun.reflect.LangReflectAccess. 110 */ 111 Method(Class<?> declaringClass, 112 String name, 113 Class<?>[] parameterTypes, 114 Class<?> returnType, 115 Class<?>[] checkedExceptions, 116 int modifiers, 117 int slot, 118 String signature, 119 byte[] annotations, 120 byte[] parameterAnnotations, 121 byte[] annotationDefault) { 122 this.clazz = declaringClass; 123 this.name = name; 124 this.parameterTypes = parameterTypes; 125 this.returnType = returnType; 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 this.annotationDefault = annotationDefault; 133 } 134 135 /** 136 * Package-private routine (exposed to java.lang.Class via 137 * ReflectAccess) which returns a copy of this Method. The copy's 138 * "root" field points to this Method. 139 */ 140 Method copy() { 141 // This routine enables sharing of MethodAccessor objects 142 // among Method objects which refer to the same underlying 143 // method in the VM. (All of this contortion is only necessary 144 // because of the "accessibility" bit in AccessibleObject, 145 // which implicitly requires that new java.lang.reflect 146 // objects be fabricated for each reflective call on Class 147 // objects.) 148 Method res = new Method(clazz, name, parameterTypes, returnType, 149 exceptionTypes, modifiers, slot, signature, 150 annotations, parameterAnnotations, annotationDefault); 151 res.root = this; 152 // Might as well eagerly propagate this if already present 153 res.methodAccessor = methodAccessor; 154 155 res.typeAnnotations = typeAnnotations; 156 return res; 157 } 158 159 @Override 160 boolean hasGenericInformation() { 161 return (getGenericSignature() != null); 162 } 163 164 @Override 165 byte[] getAnnotationBytes() { 166 return annotations; 167 } 168 169 /** 170 * {@inheritDoc} 171 */ 172 @Override 173 public Class<?> getDeclaringClass() { 174 return clazz; 175 } 176 177 /** 178 * Returns the name of the method represented by this {@code Method} 179 * object, as a {@code String}. 180 */ 181 @Override 182 public String getName() { 183 return name; 184 } 185 186 /** 187 * {@inheritDoc} 188 */ 189 @Override 190 public int getModifiers() { 191 return modifiers; 192 } 193 194 /** 195 * {@inheritDoc} 196 * @throws GenericSignatureFormatError {@inheritDoc} 197 * @since 1.5 198 */ 199 @Override 200 @SuppressWarnings({"rawtypes", "unchecked"}) 201 public TypeVariable<Method>[] getTypeParameters() { 202 if (getGenericSignature() != null) 203 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters(); 204 else 205 return (TypeVariable<Method>[])new TypeVariable[0]; 206 } 207 208 /** 209 * Returns a {@code Class} object that represents the formal return type 210 * of the method represented by this {@code Method} object. 211 * 212 * @return the return type for the method this object represents 213 */ 214 public Class<?> getReturnType() { 215 return returnType; 216 } 217 218 /** 219 * Returns a {@code Type} object that represents the formal return 220 * type of the method represented by this {@code Method} object. 221 * 222 * <p>If the return type is a parameterized type, 223 * the {@code Type} object returned must accurately reflect 224 * the actual type parameters used in the source code. 225 * 226 * <p>If the return type is a type variable or a parameterized type, it 227 * is created. Otherwise, it is resolved. 228 * 229 * @return a {@code Type} object that represents the formal return 230 * type of the underlying method 231 * @throws GenericSignatureFormatError 232 * if the generic method signature does not conform to the format 233 * specified in 234 * <cite>The Java™ Virtual Machine Specification</cite> 235 * @throws TypeNotPresentException if the underlying method's 236 * return type refers to a non-existent type declaration 237 * @throws MalformedParameterizedTypeException if the 238 * underlying method's return typed refers to a parameterized 239 * type that cannot be instantiated for any reason 240 * @since 1.5 241 */ 242 public Type getGenericReturnType() { 243 if (getGenericSignature() != null) { 244 return getGenericInfo().getReturnType(); 245 } else { return getReturnType();} 246 } 247 248 /** 249 * {@inheritDoc} 250 */ 251 @Override 252 public Class<?>[] getParameterTypes() { 253 return parameterTypes.clone(); 254 } 255 256 /** 257 * {@inheritDoc} 258 * @throws GenericSignatureFormatError {@inheritDoc} 259 * @throws TypeNotPresentException {@inheritDoc} 260 * @throws MalformedParameterizedTypeException {@inheritDoc} 261 * @since 1.5 262 */ 263 @Override 264 public Type[] getGenericParameterTypes() { 265 return super.getGenericParameterTypes(); 266 } 267 268 /** 269 * {@inheritDoc} 270 */ 271 @Override 272 public Class<?>[] getExceptionTypes() { 273 return exceptionTypes.clone(); 274 } 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[] getGenericExceptionTypes() { 285 return super.getGenericExceptionTypes(); 286 } 287 288 /** 289 * Compares this {@code Method} against the specified object. Returns 290 * true if the objects are the same. Two {@code Methods} are the same if 291 * they were declared by the same class and have the same name 292 * and formal parameter types and return type. 293 */ 294 public boolean equals(Object obj) { 295 if (obj != null && obj instanceof Method) { 296 Method other = (Method)obj; 297 if ((getDeclaringClass() == other.getDeclaringClass()) 298 && (getName() == other.getName())) { 299 if (!returnType.equals(other.getReturnType())) 300 return false; 301 return equalParamTypes(parameterTypes, other.parameterTypes); 302 } 303 } 304 return false; 305 } 306 307 /** 308 * Returns a hashcode for this {@code Method}. The hashcode is computed 309 * as the exclusive-or of the hashcodes for the underlying 310 * method's declaring class name and the method's name. 311 */ 312 public int hashCode() { 313 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 314 } 315 316 /** 317 * Returns a string describing this {@code Method}. The string is 318 * formatted as the method access modifiers, if any, followed by 319 * the method return type, followed by a space, followed by the 320 * class declaring the method, followed by a period, followed by 321 * the method name, followed by a parenthesized, comma-separated 322 * list of the method's formal parameter types. If the method 323 * throws checked exceptions, the parameter list is followed by a 324 * space, followed by the word throws followed by a 325 * comma-separated list of the thrown exception types. 326 * For example: 327 * <pre> 328 * public boolean java.lang.Object.equals(java.lang.Object) 329 * </pre> 330 * 331 * <p>The access modifiers are placed in canonical order as 332 * specified by "The Java Language Specification". This is 333 * {@code public}, {@code protected} or {@code private} first, 334 * and then other modifiers in the following order: 335 * {@code abstract}, {@code static}, {@code final}, 336 * {@code synchronized}, {@code native}, {@code strictfp}. 337 */ 338 public String toString() { 339 return sharedToString(Modifier.methodModifiers(), 340 parameterTypes, 341 exceptionTypes); 342 } 343 344 @Override 345 void specificToStringHeader(StringBuilder sb) { 346 sb.append(Field.getTypeName(getReturnType())).append(' '); 347 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 348 sb.append(getName()); 349 } 350 351 /** 352 * Returns a string describing this {@code Method}, including 353 * type parameters. The string is formatted as the method access 354 * modifiers, if any, followed by an angle-bracketed 355 * comma-separated list of the method's type parameters, if any, 356 * followed by the method's generic return type, followed by a 357 * space, followed by the class declaring the method, followed by 358 * a period, followed by the method name, followed by a 359 * parenthesized, comma-separated list of the method's generic 360 * formal parameter types. 361 * 362 * If this method was declared to take a variable number of 363 * arguments, instead of denoting the last parameter as 364 * "<tt><i>Type</i>[]</tt>", it is denoted as 365 * "<tt><i>Type</i>...</tt>". 366 * 367 * A space is used to separate access modifiers from one another 368 * and from the type parameters or return type. If there are no 369 * type parameters, the type parameter list is elided; if the type 370 * parameter list is present, a space separates the list from the 371 * class name. If the method is declared to throw exceptions, the 372 * parameter list is followed by a space, followed by the word 373 * throws followed by a comma-separated list of the generic thrown 374 * exception types. If there are no type parameters, the type 375 * parameter list is elided. 376 * 377 * <p>The access modifiers are placed in canonical order as 378 * specified by "The Java Language Specification". This is 379 * {@code public}, {@code protected} or {@code private} first, 380 * and then other modifiers in the following order: 381 * {@code abstract}, {@code static}, {@code final}, 382 * {@code synchronized}, {@code native}, {@code strictfp}. 383 * 384 * @return a string describing this {@code Method}, 385 * include type parameters 386 * 387 * @since 1.5 388 */ 389 @Override 390 public String toGenericString() { 391 return sharedToGenericString(Modifier.methodModifiers()); 392 } 393 394 @Override 395 void specificToGenericStringHeader(StringBuilder sb) { 396 Type genRetType = getGenericReturnType(); 397 sb.append( ((genRetType instanceof Class<?>)? 398 Field.getTypeName((Class<?>)genRetType):genRetType.toString())) 399 .append(' '); 400 401 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 402 sb.append(getName()); 403 } 404 405 /** 406 * Invokes the underlying method represented by this {@code Method} 407 * object, on the specified object with the specified parameters. 408 * Individual parameters are automatically unwrapped to match 409 * primitive formal parameters, and both primitive and reference 410 * parameters are subject to method invocation conversions as 411 * necessary. 412 * 413 * <p>If the underlying method is static, then the specified {@code obj} 414 * argument is ignored. It may be null. 415 * 416 * <p>If the number of formal parameters required by the underlying method is 417 * 0, the supplied {@code args} array may be of length 0 or null. 418 * 419 * <p>If the underlying method is an instance method, it is invoked 420 * using dynamic method lookup as documented in The Java Language 421 * Specification, Second Edition, section 15.12.4.4; in particular, 422 * overriding based on the runtime type of the target object will occur. 423 * 424 * <p>If the underlying method is static, the class that declared 425 * the method is initialized if it has not already been initialized. 426 * 427 * <p>If the method completes normally, the value it returns is 428 * returned to the caller of invoke; if the value has a primitive 429 * type, it is first appropriately wrapped in an object. However, 430 * if the value has the type of an array of a primitive type, the 431 * elements of the array are <i>not</i> wrapped in objects; in 432 * other words, an array of primitive type is returned. If the 433 * underlying method return type is void, the invocation returns 434 * null. 435 * 436 * @param obj the object the underlying method is invoked from 437 * @param args the arguments used for the method call 438 * @return the result of dispatching the method represented by 439 * this object on {@code obj} with parameters 440 * {@code args} 441 * 442 * @exception IllegalAccessException if this {@code Method} object 443 * is enforcing Java language access control and the underlying 444 * method is inaccessible. 445 * @exception IllegalArgumentException if the method is an 446 * instance method and the specified object argument 447 * is not an instance of the class or interface 448 * declaring the underlying method (or of a subclass 449 * or implementor thereof); if the number of actual 450 * and formal parameters differ; if an unwrapping 451 * conversion for primitive arguments fails; or if, 452 * after possible unwrapping, a parameter value 453 * cannot be converted to the corresponding formal 454 * parameter type by a method invocation conversion. 455 * @exception InvocationTargetException if the underlying method 456 * throws an exception. 457 * @exception NullPointerException if the specified object is null 458 * and the method is an instance method. 459 * @exception ExceptionInInitializerError if the initialization 460 * provoked by this method fails. 461 */ 462 public Object invoke(Object obj, Object... args) 463 throws IllegalAccessException, IllegalArgumentException, 464 InvocationTargetException 465 { 466 if (!override) { 467 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 468 Class<?> caller = Reflection.getCallerClass(1); 469 470 checkAccess(caller, clazz, obj, modifiers); 471 } 472 } 473 MethodAccessor ma = methodAccessor; // read volatile 474 if (ma == null) { 475 ma = acquireMethodAccessor(); 476 } 477 return ma.invoke(obj, args); 478 } 479 480 /** 481 * Returns {@code true} if this method is a bridge 482 * method; returns {@code false} otherwise. 483 * 484 * @return true if and only if this method is a bridge 485 * method as defined by the Java Language Specification. 486 * @since 1.5 487 */ 488 public boolean isBridge() { 489 return (getModifiers() & Modifier.BRIDGE) != 0; 490 } 491 492 /** 493 * {@inheritDoc} 494 * @since 1.5 495 */ 496 @Override 497 public boolean isVarArgs() { 498 return super.isVarArgs(); 499 } 500 501 /** 502 * {@inheritDoc} 503 * @jls 13.1 The Form of a Binary 504 * @since 1.5 505 */ 506 @Override 507 public boolean isSynthetic() { 508 return super.isSynthetic(); 509 } 510 511 /** 512 * Returns {@code true} if this method is a default 513 * method; returns {@code false} otherwise. 514 * 515 * A default method is a non-abstract method, that is, a method 516 * with a body, declared in an interface type. 517 * 518 * @return true if and only if this method is a default 519 * method as defined by the Java Language Specification. 520 * @since 1.8 521 */ 522 public boolean isDefault() { 523 return (getModifiers() & Modifier.ABSTRACT) == 0 && 524 getDeclaringClass().isInterface(); 525 } 526 527 // NOTE that there is no synchronization used here. It is correct 528 // (though not efficient) to generate more than one MethodAccessor 529 // for a given Method. However, avoiding synchronization will 530 // probably make the implementation more scalable. 531 private MethodAccessor acquireMethodAccessor() { 532 // First check to see if one has been created yet, and take it 533 // if so 534 MethodAccessor tmp = null; 535 if (root != null) tmp = root.getMethodAccessor(); 536 if (tmp != null) { 537 methodAccessor = tmp; 538 } else { 539 // Otherwise fabricate one and propagate it up to the root 540 tmp = reflectionFactory.newMethodAccessor(this); 541 setMethodAccessor(tmp); 542 } 543 544 return tmp; 545 } 546 547 // Returns MethodAccessor for this Method object, not looking up 548 // the chain to the root 549 MethodAccessor getMethodAccessor() { 550 return methodAccessor; 551 } 552 553 // Sets the MethodAccessor for this Method object and 554 // (recursively) its root 555 void setMethodAccessor(MethodAccessor accessor) { 556 methodAccessor = accessor; 557 // Propagate up 558 if (root != null) { 559 root.setMethodAccessor(accessor); 560 } 561 } 562 563 /** 564 * Returns the default value for the annotation member represented by 565 * this {@code Method} instance. If the member is of a primitive type, 566 * an instance of the corresponding wrapper type is returned. Returns 567 * null if no default is associated with the member, or if the method 568 * instance does not represent a declared member of an annotation type. 569 * 570 * @return the default value for the annotation member represented 571 * by this {@code Method} instance. 572 * @throws TypeNotPresentException if the annotation is of type 573 * {@link Class} and no definition can be found for the 574 * default class value. 575 * @since 1.5 576 */ 577 public Object getDefaultValue() { 578 if (annotationDefault == null) 579 return null; 580 Class<?> memberType = AnnotationType.invocationHandlerReturnType( 581 getReturnType()); 582 Object result = AnnotationParser.parseMemberValue( 583 memberType, ByteBuffer.wrap(annotationDefault), 584 sun.misc.SharedSecrets.getJavaLangAccess(). 585 getConstantPool(getDeclaringClass()), 586 getDeclaringClass()); 587 if (result instanceof sun.reflect.annotation.ExceptionProxy) 588 throw new AnnotationFormatError("Invalid default: " + this); 589 return result; 590 } 591 592 /** 593 * {@inheritDoc} 594 * @throws NullPointerException {@inheritDoc} 595 * @since 1.5 596 */ 597 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 598 return super.getAnnotation(annotationClass); 599 } 600 601 /** 602 * {@inheritDoc} 603 * @since 1.5 604 */ 605 public Annotation[] getDeclaredAnnotations() { 606 return super.getDeclaredAnnotations(); 607 } 608 609 /** 610 * {@inheritDoc} 611 * @since 1.5 612 */ 613 @Override 614 public Annotation[][] getParameterAnnotations() { 615 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 616 } 617 618 @Override 619 void handleParameterNumberMismatch(int resultLength, int numParameters) { 620 throw new AnnotationFormatError("Parameter annotations don't match number of parameters"); 621 } 622 }