1 /* 2 * Copyright (c) 1996, 2011, 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 83 84 // Generics infrastructure 85 private String getGenericSignature() {return signature;} 86 87 // Accessor for factory 88 private GenericsFactory getFactory() { 89 // create scope and factory 90 return CoreReflectionFactory.make(this, MethodScope.make(this)); 91 } 92 93 // Accessor for generic info repository 94 @Override 95 MethodRepository getGenericInfo() { 96 // lazily initialize repository if necessary 97 if (genericInfo == null) { 98 // create and cache generic info repository 99 genericInfo = MethodRepository.make(getGenericSignature(), 100 getFactory()); 101 } 102 return genericInfo; //return cached repository 103 } 104 105 /** 106 * Package-private constructor used by ReflectAccess to enable 107 * instantiation of these objects in Java code from the java.lang 108 * package via sun.reflect.LangReflectAccess. 109 */ 110 Method(Class<?> declaringClass, 111 String name, 112 Class<?>[] parameterTypes, 113 Class<?> returnType, 114 Class<?>[] checkedExceptions, 115 int modifiers, 116 int slot, 117 String signature, 118 byte[] annotations, 119 byte[] parameterAnnotations, 120 byte[] annotationDefault) { 121 this.clazz = declaringClass; 122 this.name = name; 123 this.parameterTypes = parameterTypes; 124 this.returnType = returnType; 125 this.exceptionTypes = checkedExceptions; 126 this.modifiers = modifiers; 127 this.slot = slot; 128 this.signature = signature; 129 this.annotations = annotations; 130 this.parameterAnnotations = parameterAnnotations; 131 this.annotationDefault = annotationDefault; 132 } 133 134 /** 135 * Package-private routine (exposed to java.lang.Class via 136 * ReflectAccess) which returns a copy of this Method. The copy's 137 * "root" field points to this Method. 138 */ 139 Method copy() { 140 // This routine enables sharing of MethodAccessor objects 141 // among Method 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 Method res = new Method(clazz, name, parameterTypes, returnType, 148 exceptionTypes, modifiers, slot, signature, 149 annotations, parameterAnnotations, annotationDefault); 150 res.root = this; 151 // Might as well eagerly propagate this if already present 152 res.methodAccessor = methodAccessor; 153 return res; 154 } 155 156 @Override 157 boolean hasGenericInformation() { 158 return (getGenericSignature() != null); 159 } 160 161 @Override 162 byte[] getAnnotationBytes() { 163 return annotations; 164 } 165 166 /** 167 * {@inheritDoc} 168 */ 169 @Override 170 public Class<?> getDeclaringClass() { 171 return clazz; 172 } 173 174 /** 175 * Returns the name of the method represented by this {@code Method} 176 * object, as a {@code String}. 177 */ 178 @Override 179 public String getName() { 180 return name; 181 } 182 183 /** 184 * {@inheritDoc} 185 */ 186 @Override 187 public int getModifiers() { 188 return modifiers; 189 } 190 191 /** 192 * {@inheritDoc} 193 * @throws GenericSignatureFormatError {@inheritDoc} 194 * @since 1.5 195 */ 196 @Override 197 @SuppressWarnings({ "rawtypes", "unchecked" }) 198 public TypeVariable<Method>[] getTypeParameters() { 199 if (getGenericSignature() != null) 200 return (TypeVariable<Method>[])getGenericInfo().getTypeParameters(); 201 else 202 return (TypeVariable<Method>[])new TypeVariable[0]; 203 } 204 205 /** 206 * Returns a {@code Class} object that represents the formal return type 207 * of the method represented by this {@code Method} object. 208 * 209 * @return the return type for the method this object represents 210 */ 211 public Class<?> getReturnType() { 212 return returnType; 213 } 214 215 /** 216 * Returns a {@code Type} object that represents the formal return 217 * type of the method represented by this {@code Method} object. 218 * 219 * <p>If the return type is a parameterized type, 220 * the {@code Type} object returned must accurately reflect 221 * the actual type parameters used in the source code. 222 * 223 * <p>If the return type is a type variable or a parameterized type, it 224 * is created. Otherwise, it is resolved. 225 * 226 * @return a {@code Type} object that represents the formal return 227 * type of the underlying method 228 * @throws GenericSignatureFormatError 229 * if the generic method signature does not conform to the format 230 * specified in 231 * <cite>The Java™ Virtual Machine Specification</cite> 232 * @throws TypeNotPresentException if the underlying method's 233 * return type refers to a non-existent type declaration 234 * @throws MalformedParameterizedTypeException if the 235 * underlying method's return typed refers to a parameterized 236 * type that cannot be instantiated for any reason 237 * @since 1.5 238 */ 239 public Type getGenericReturnType() { 240 if (getGenericSignature() != null) { 241 return getGenericInfo().getReturnType(); 242 } else { return getReturnType();} 243 } 244 245 /** 246 * {@inheritDoc} 247 */ 248 @Override 249 public Class<?>[] getParameterTypes() { 250 return parameterTypes.clone(); 251 } 252 253 /** 254 * {@inheritDoc} 255 * @throws GenericSignatureFormatError {@inheritDoc} 256 * @throws TypeNotPresentException {@inheritDoc} 257 * @throws MalformedParameterizedTypeException {@inheritDoc} 258 * @since 1.5 259 */ 260 @Override 261 public Type[] getGenericParameterTypes() { 262 return super.getGenericParameterTypes(); 263 } 264 265 /** 266 * {@inheritDoc} 267 */ 268 @Override 269 public Class<?>[] getExceptionTypes() { 270 return exceptionTypes.clone(); 271 } 272 273 /** 274 * {@inheritDoc} 275 * @throws GenericSignatureFormatError {@inheritDoc} 276 * @throws TypeNotPresentException {@inheritDoc} 277 * @throws MalformedParameterizedTypeException {@inheritDoc} 278 * @since 1.5 279 */ 280 @Override 281 public Type[] getGenericExceptionTypes() { 282 return super.getGenericExceptionTypes(); 283 } 284 285 /** 286 * Compares this {@code Method} against the specified object. Returns 287 * true if the objects are the same. Two {@code Methods} are the same if 288 * they were declared by the same class and have the same name 289 * and formal parameter types and return type. 290 */ 291 public boolean equals(Object obj) { 292 if (obj != null && obj instanceof Method) { 293 Method other = (Method)obj; 294 if ((getDeclaringClass() == other.getDeclaringClass()) 295 && (getName() == other.getName())) { 296 if (!returnType.equals(other.getReturnType())) 297 return false; 298 return equalParamTypes(parameterTypes, other.parameterTypes); 299 } 300 } 301 return false; 302 } 303 304 /** 305 * Returns a hashcode for this {@code Method}. The hashcode is computed 306 * as the exclusive-or of the hashcodes for the underlying 307 * method's declaring class name and the method's name. 308 */ 309 public int hashCode() { 310 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 311 } 312 313 /** 314 * Returns a string describing this {@code Method}. The string is 315 * formatted as the method access modifiers, if any, followed by 316 * the method return type, followed by a space, followed by the 317 * class declaring the method, followed by a period, followed by 318 * the method name, followed by a parenthesized, comma-separated 319 * list of the method's formal parameter types. If the method 320 * throws checked exceptions, the parameter list is followed by a 321 * space, followed by the word throws followed by a 322 * comma-separated list of the thrown exception types. 323 * For example: 324 * <pre> 325 * public boolean java.lang.Object.equals(java.lang.Object) 326 * </pre> 327 * 328 * <p>The access modifiers are placed in canonical order as 329 * specified by "The Java Language Specification". This is 330 * {@code public}, {@code protected} or {@code private} first, 331 * and then other modifiers in the following order: 332 * {@code abstract}, {@code static}, {@code final}, 333 * {@code synchronized}, {@code native}, {@code strictfp}. 334 */ 335 public String toString() { 336 return sharedToString(Modifier.methodModifiers(), 337 parameterTypes, 338 exceptionTypes); 339 } 340 341 @Override 342 void specificToStringHeader(StringBuilder sb) { 343 sb.append(Field.getTypeName(getReturnType())).append(' '); 344 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 345 sb.append(getName()); 346 } 347 348 /** 349 * Returns a string describing this {@code Method}, including 350 * type parameters. The string is formatted as the method access 351 * modifiers, if any, followed by an angle-bracketed 352 * comma-separated list of the method's type parameters, if any, 353 * followed by the method's generic return type, followed by a 354 * space, followed by the class declaring the method, followed by 355 * a period, followed by the method name, followed by a 356 * parenthesized, comma-separated list of the method's generic 357 * formal parameter types. 358 * 359 * If this method was declared to take a variable number of 360 * arguments, instead of denoting the last parameter as 361 * "<tt><i>Type</i>[]</tt>", it is denoted as 362 * "<tt><i>Type</i>...</tt>". 363 * 364 * A space is used to separate access modifiers from one another 365 * and from the type parameters or return type. If there are no 366 * type parameters, the type parameter list is elided; if the type 367 * parameter list is present, a space separates the list from the 368 * class name. If the method is declared to throw exceptions, the 369 * parameter list is followed by a space, followed by the word 370 * throws followed by a comma-separated list of the generic thrown 371 * exception types. If there are no type parameters, the type 372 * parameter list is elided. 373 * 374 * <p>The access modifiers are placed in canonical order as 375 * specified by "The Java Language Specification". This is 376 * {@code public}, {@code protected} or {@code private} first, 377 * and then other modifiers in the following order: 378 * {@code abstract}, {@code static}, {@code final}, 379 * {@code synchronized}, {@code native}, {@code strictfp}. 380 * 381 * @return a string describing this {@code Method}, 382 * include type parameters 383 * 384 * @since 1.5 385 */ 386 @Override 387 public String toGenericString() { 388 return sharedToGenericString(Modifier.methodModifiers()); 389 } 390 391 @Override 392 void specificToGenericStringHeader(StringBuilder sb) { 393 Type genRetType = getGenericReturnType(); 394 sb.append( ((genRetType instanceof Class<?>)? 395 Field.getTypeName((Class<?>)genRetType):genRetType.toString())) 396 .append(' '); 397 398 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 399 sb.append(getName()); 400 } 401 402 /** 403 * Invokes the underlying method represented by this {@code Method} 404 * object, on the specified object with the specified parameters. 405 * Individual parameters are automatically unwrapped to match 406 * primitive formal parameters, and both primitive and reference 407 * parameters are subject to method invocation conversions as 408 * necessary. 409 * 410 * <p>If the underlying method is static, then the specified {@code obj} 411 * argument is ignored. It may be null. 412 * 413 * <p>If the number of formal parameters required by the underlying method is 414 * 0, the supplied {@code args} array may be of length 0 or null. 415 * 416 * <p>If the underlying method is an instance method, it is invoked 417 * using dynamic method lookup as documented in The Java Language 418 * Specification, Second Edition, section 15.12.4.4; in particular, 419 * overriding based on the runtime type of the target object will occur. 420 * 421 * <p>If the underlying method is static, the class that declared 422 * the method is initialized if it has not already been initialized. 423 * 424 * <p>If the method completes normally, the value it returns is 425 * returned to the caller of invoke; if the value has a primitive 426 * type, it is first appropriately wrapped in an object. However, 427 * if the value has the type of an array of a primitive type, the 428 * elements of the array are <i>not</i> wrapped in objects; in 429 * other words, an array of primitive type is returned. If the 430 * underlying method return type is void, the invocation returns 431 * null. 432 * 433 * @param obj the object the underlying method is invoked from 434 * @param args the arguments used for the method call 435 * @return the result of dispatching the method represented by 436 * this object on {@code obj} with parameters 437 * {@code args} 438 * 439 * @exception IllegalAccessException if this {@code Method} object 440 * is enforcing Java language access control and the underlying 441 * method is inaccessible. 442 * @exception IllegalArgumentException if the method is an 443 * instance method and the specified object argument 444 * is not an instance of the class or interface 445 * declaring the underlying method (or of a subclass 446 * or implementor thereof); if the number of actual 447 * and formal parameters differ; if an unwrapping 448 * conversion for primitive arguments fails; or if, 449 * after possible unwrapping, a parameter value 450 * cannot be converted to the corresponding formal 451 * parameter type by a method invocation conversion. 452 * @exception InvocationTargetException if the underlying method 453 * throws an exception. 454 * @exception NullPointerException if the specified object is null 455 * and the method is an instance method. 456 * @exception ExceptionInInitializerError if the initialization 457 * provoked by this method fails. 458 */ 459 public Object invoke(Object obj, Object... args) 460 throws IllegalAccessException, IllegalArgumentException, 461 InvocationTargetException 462 { 463 if (!override) { 464 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 465 Class<?> caller = Reflection.getCallerClass(1); 466 467 checkAccess(caller, clazz, obj, modifiers); 468 } 469 } 470 MethodAccessor ma = methodAccessor; // read volatile 471 if (ma == null) { 472 ma = acquireMethodAccessor(); 473 } 474 return ma.invoke(obj, args); 475 } 476 477 /** 478 * Returns {@code true} if this method is a bridge 479 * method; returns {@code false} otherwise. 480 * 481 * @return true if and only if this method is a bridge 482 * method as defined by the Java Language Specification. 483 * @since 1.5 484 */ 485 public boolean isBridge() { 486 return (getModifiers() & Modifier.BRIDGE) != 0; 487 } 488 489 /** 490 * {@inheritDoc} 491 * @since 1.5 492 */ 493 @Override 494 public boolean isVarArgs() { 495 return super.isVarArgs(); 496 } 497 498 /** 499 * {@inheritDoc} 500 * @since 1.5 501 */ 502 @Override 503 public boolean isSynthetic() { 504 return super.isSynthetic(); 505 } 506 507 // NOTE that there is no synchronization used here. It is correct 508 // (though not efficient) to generate more than one MethodAccessor 509 // for a given Method. However, avoiding synchronization will 510 // probably make the implementation more scalable. 511 private MethodAccessor acquireMethodAccessor() { 512 // First check to see if one has been created yet, and take it 513 // if so 514 MethodAccessor tmp = null; 515 if (root != null) tmp = root.getMethodAccessor(); 516 if (tmp != null) { 517 methodAccessor = tmp; 518 } else { 519 // Otherwise fabricate one and propagate it up to the root 520 tmp = reflectionFactory.newMethodAccessor(this); 521 setMethodAccessor(tmp); 522 } 523 524 return tmp; 525 } 526 527 // Returns MethodAccessor for this Method object, not looking up 528 // the chain to the root 529 MethodAccessor getMethodAccessor() { 530 return methodAccessor; 531 } 532 533 // Sets the MethodAccessor for this Method object and 534 // (recursively) its root 535 void setMethodAccessor(MethodAccessor accessor) { 536 methodAccessor = accessor; 537 // Propagate up 538 if (root != null) { 539 root.setMethodAccessor(accessor); 540 } 541 } 542 543 /** 544 * Returns the default value for the annotation member represented by 545 * this {@code Method} instance. If the member is of a primitive type, 546 * an instance of the corresponding wrapper type is returned. Returns 547 * null if no default is associated with the member, or if the method 548 * instance does not represent a declared member of an annotation type. 549 * 550 * @return the default value for the annotation member represented 551 * by this {@code Method} instance. 552 * @throws TypeNotPresentException if the annotation is of type 553 * {@link Class} and no definition can be found for the 554 * default class value. 555 * @since 1.5 556 */ 557 public Object getDefaultValue() { 558 if (annotationDefault == null) 559 return null; 560 Class<?> memberType = AnnotationType.invocationHandlerReturnType( 561 getReturnType()); 562 Object result = AnnotationParser.parseMemberValue( 563 memberType, ByteBuffer.wrap(annotationDefault), 564 sun.misc.SharedSecrets.getJavaLangAccess(). 565 getConstantPool(getDeclaringClass()), 566 getDeclaringClass()); 567 if (result instanceof sun.reflect.annotation.ExceptionProxy) 568 throw new AnnotationFormatError("Invalid default: " + this); 569 return result; 570 } 571 572 /** 573 * {@inheritDoc} 574 * @throws NullPointerException {@inheritDoc} 575 * @since 1.5 576 */ 577 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 578 return super.getAnnotation(annotationClass); 579 } 580 581 /** 582 * {@inheritDoc} 583 * @since 1.5 584 */ 585 public Annotation[] getDeclaredAnnotations() { 586 return super.getDeclaredAnnotations(); 587 } 588 589 /** 590 * {@inheritDoc} 591 * @since 1.5 592 */ 593 @Override 594 public Annotation[][] getParameterAnnotations() { 595 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 596 } 597 598 @Override 599 void handleParameterNumberMismatch(int resultLength, int numParameters) { 600 throw new AnnotationFormatError("Parameter annotations don't match number of parameters"); 601 } 602 }