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 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 */ 256 public int getNumParameters() { return parameterTypes.length; } 257 258 259 /** 260 * {@inheritDoc} 261 * @throws GenericSignatureFormatError {@inheritDoc} 262 * @throws TypeNotPresentException {@inheritDoc} 263 * @throws MalformedParameterizedTypeException {@inheritDoc} 264 * @since 1.5 265 */ 266 @Override 267 public Type[] getGenericParameterTypes() { 268 return super.getGenericParameterTypes(); 269 } 270 271 /** 272 * {@inheritDoc} 273 */ 274 @Override 275 public Class<?>[] getExceptionTypes() { 276 return exceptionTypes.clone(); 277 } 278 279 /** 280 * {@inheritDoc} 281 * @throws GenericSignatureFormatError {@inheritDoc} 282 * @throws TypeNotPresentException {@inheritDoc} 283 * @throws MalformedParameterizedTypeException {@inheritDoc} 284 * @since 1.5 285 */ 286 @Override 287 public Type[] getGenericExceptionTypes() { 288 return super.getGenericExceptionTypes(); 289 } 290 291 /** 292 * Compares this {@code Method} against the specified object. Returns 293 * true if the objects are the same. Two {@code Methods} are the same if 294 * they were declared by the same class and have the same name 295 * and formal parameter types and return type. 296 */ 297 public boolean equals(Object obj) { 298 if (obj != null && obj instanceof Method) { 299 Method other = (Method)obj; 300 if ((getDeclaringClass() == other.getDeclaringClass()) 301 && (getName() == other.getName())) { 302 if (!returnType.equals(other.getReturnType())) 303 return false; 304 return equalParamTypes(parameterTypes, other.parameterTypes); 305 } 306 } 307 return false; 308 } 309 310 /** 311 * Returns a hashcode for this {@code Method}. The hashcode is computed 312 * as the exclusive-or of the hashcodes for the underlying 313 * method's declaring class name and the method's name. 314 */ 315 public int hashCode() { 316 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 317 } 318 319 /** 320 * Returns a string describing this {@code Method}. The string is 321 * formatted as the method access modifiers, if any, followed by 322 * the method return type, followed by a space, followed by the 323 * class declaring the method, followed by a period, followed by 324 * the method name, followed by a parenthesized, comma-separated 325 * list of the method's formal parameter types. If the method 326 * throws checked exceptions, the parameter list is followed by a 327 * space, followed by the word throws followed by a 328 * comma-separated list of the thrown exception types. 329 * For example: 330 * <pre> 331 * public boolean java.lang.Object.equals(java.lang.Object) 332 * </pre> 333 * 334 * <p>The access modifiers are placed in canonical order as 335 * specified by "The Java Language Specification". This is 336 * {@code public}, {@code protected} or {@code private} first, 337 * and then other modifiers in the following order: 338 * {@code abstract}, {@code static}, {@code final}, 339 * {@code synchronized}, {@code native}, {@code strictfp}. 340 */ 341 public String toString() { 342 return sharedToString(Modifier.methodModifiers(), 343 parameterTypes, 344 exceptionTypes); 345 } 346 347 @Override 348 void specificToStringHeader(StringBuilder sb) { 349 sb.append(Field.getTypeName(getReturnType())).append(' '); 350 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 351 sb.append(getName()); 352 } 353 354 /** 355 * Returns a string describing this {@code Method}, including 356 * type parameters. The string is formatted as the method access 357 * modifiers, if any, followed by an angle-bracketed 358 * comma-separated list of the method's type parameters, if any, 359 * followed by the method's generic return type, followed by a 360 * space, followed by the class declaring the method, followed by 361 * a period, followed by the method name, followed by a 362 * parenthesized, comma-separated list of the method's generic 363 * formal parameter types. 364 * 365 * If this method was declared to take a variable number of 366 * arguments, instead of denoting the last parameter as 367 * "<tt><i>Type</i>[]</tt>", it is denoted as 368 * "<tt><i>Type</i>...</tt>". 369 * 370 * A space is used to separate access modifiers from one another 371 * and from the type parameters or return type. If there are no 372 * type parameters, the type parameter list is elided; if the type 373 * parameter list is present, a space separates the list from the 374 * class name. If the method is declared to throw exceptions, the 375 * parameter list is followed by a space, followed by the word 376 * throws followed by a comma-separated list of the generic thrown 377 * exception types. If there are no type parameters, the type 378 * parameter list is elided. 379 * 380 * <p>The access modifiers are placed in canonical order as 381 * specified by "The Java Language Specification". This is 382 * {@code public}, {@code protected} or {@code private} first, 383 * and then other modifiers in the following order: 384 * {@code abstract}, {@code static}, {@code final}, 385 * {@code synchronized}, {@code native}, {@code strictfp}. 386 * 387 * @return a string describing this {@code Method}, 388 * include type parameters 389 * 390 * @since 1.5 391 */ 392 @Override 393 public String toGenericString() { 394 return sharedToGenericString(Modifier.methodModifiers()); 395 } 396 397 @Override 398 void specificToGenericStringHeader(StringBuilder sb) { 399 Type genRetType = getGenericReturnType(); 400 sb.append( ((genRetType instanceof Class<?>)? 401 Field.getTypeName((Class<?>)genRetType):genRetType.toString())) 402 .append(' '); 403 404 sb.append(Field.getTypeName(getDeclaringClass())).append('.'); 405 sb.append(getName()); 406 } 407 408 /** 409 * Invokes the underlying method represented by this {@code Method} 410 * object, on the specified object with the specified parameters. 411 * Individual parameters are automatically unwrapped to match 412 * primitive formal parameters, and both primitive and reference 413 * parameters are subject to method invocation conversions as 414 * necessary. 415 * 416 * <p>If the underlying method is static, then the specified {@code obj} 417 * argument is ignored. It may be null. 418 * 419 * <p>If the number of formal parameters required by the underlying method is 420 * 0, the supplied {@code args} array may be of length 0 or null. 421 * 422 * <p>If the underlying method is an instance method, it is invoked 423 * using dynamic method lookup as documented in The Java Language 424 * Specification, Second Edition, section 15.12.4.4; in particular, 425 * overriding based on the runtime type of the target object will occur. 426 * 427 * <p>If the underlying method is static, the class that declared 428 * the method is initialized if it has not already been initialized. 429 * 430 * <p>If the method completes normally, the value it returns is 431 * returned to the caller of invoke; if the value has a primitive 432 * type, it is first appropriately wrapped in an object. However, 433 * if the value has the type of an array of a primitive type, the 434 * elements of the array are <i>not</i> wrapped in objects; in 435 * other words, an array of primitive type is returned. If the 436 * underlying method return type is void, the invocation returns 437 * null. 438 * 439 * @param obj the object the underlying method is invoked from 440 * @param args the arguments used for the method call 441 * @return the result of dispatching the method represented by 442 * this object on {@code obj} with parameters 443 * {@code args} 444 * 445 * @exception IllegalAccessException if this {@code Method} object 446 * is enforcing Java language access control and the underlying 447 * method is inaccessible. 448 * @exception IllegalArgumentException if the method is an 449 * instance method and the specified object argument 450 * is not an instance of the class or interface 451 * declaring the underlying method (or of a subclass 452 * or implementor thereof); if the number of actual 453 * and formal parameters differ; if an unwrapping 454 * conversion for primitive arguments fails; or if, 455 * after possible unwrapping, a parameter value 456 * cannot be converted to the corresponding formal 457 * parameter type by a method invocation conversion. 458 * @exception InvocationTargetException if the underlying method 459 * throws an exception. 460 * @exception NullPointerException if the specified object is null 461 * and the method is an instance method. 462 * @exception ExceptionInInitializerError if the initialization 463 * provoked by this method fails. 464 */ 465 public Object invoke(Object obj, Object... args) 466 throws IllegalAccessException, IllegalArgumentException, 467 InvocationTargetException 468 { 469 if (!override) { 470 if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { 471 Class<?> caller = Reflection.getCallerClass(1); 472 473 checkAccess(caller, clazz, obj, modifiers); 474 } 475 } 476 MethodAccessor ma = methodAccessor; // read volatile 477 if (ma == null) { 478 ma = acquireMethodAccessor(); 479 } 480 return ma.invoke(obj, args); 481 } 482 483 /** 484 * Returns {@code true} if this method is a bridge 485 * method; returns {@code false} otherwise. 486 * 487 * @return true if and only if this method is a bridge 488 * method as defined by the Java Language Specification. 489 * @since 1.5 490 */ 491 public boolean isBridge() { 492 return (getModifiers() & Modifier.BRIDGE) != 0; 493 } 494 495 /** 496 * {@inheritDoc} 497 * @since 1.5 498 */ 499 @Override 500 public boolean isVarArgs() { 501 return super.isVarArgs(); 502 } 503 504 /** 505 * {@inheritDoc} 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 MethodAccessor 515 // for a given Method. However, avoiding synchronization will 516 // probably make the implementation more scalable. 517 private MethodAccessor acquireMethodAccessor() { 518 // First check to see if one has been created yet, and take it 519 // if so 520 MethodAccessor tmp = null; 521 if (root != null) tmp = root.getMethodAccessor(); 522 if (tmp != null) { 523 methodAccessor = tmp; 524 } else { 525 // Otherwise fabricate one and propagate it up to the root 526 tmp = reflectionFactory.newMethodAccessor(this); 527 setMethodAccessor(tmp); 528 } 529 530 return tmp; 531 } 532 533 // Returns MethodAccessor for this Method object, not looking up 534 // the chain to the root 535 MethodAccessor getMethodAccessor() { 536 return methodAccessor; 537 } 538 539 // Sets the MethodAccessor for this Method object and 540 // (recursively) its root 541 void setMethodAccessor(MethodAccessor accessor) { 542 methodAccessor = accessor; 543 // Propagate up 544 if (root != null) { 545 root.setMethodAccessor(accessor); 546 } 547 } 548 549 /** 550 * Returns the default value for the annotation member represented by 551 * this {@code Method} instance. If the member is of a primitive type, 552 * an instance of the corresponding wrapper type is returned. Returns 553 * null if no default is associated with the member, or if the method 554 * instance does not represent a declared member of an annotation type. 555 * 556 * @return the default value for the annotation member represented 557 * by this {@code Method} instance. 558 * @throws TypeNotPresentException if the annotation is of type 559 * {@link Class} and no definition can be found for the 560 * default class value. 561 * @since 1.5 562 */ 563 public Object getDefaultValue() { 564 if (annotationDefault == null) 565 return null; 566 Class<?> memberType = AnnotationType.invocationHandlerReturnType( 567 getReturnType()); 568 Object result = AnnotationParser.parseMemberValue( 569 memberType, ByteBuffer.wrap(annotationDefault), 570 sun.misc.SharedSecrets.getJavaLangAccess(). 571 getConstantPool(getDeclaringClass()), 572 getDeclaringClass()); 573 if (result instanceof sun.reflect.annotation.ExceptionProxy) 574 throw new AnnotationFormatError("Invalid default: " + this); 575 return result; 576 } 577 578 /** 579 * {@inheritDoc} 580 * @throws NullPointerException {@inheritDoc} 581 * @since 1.5 582 */ 583 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 584 return super.getAnnotation(annotationClass); 585 } 586 587 /** 588 * {@inheritDoc} 589 * @since 1.5 590 */ 591 public Annotation[] getDeclaredAnnotations() { 592 return super.getDeclaredAnnotations(); 593 } 594 595 /** 596 * {@inheritDoc} 597 * @since 1.5 598 */ 599 @Override 600 public Annotation[][] getParameterAnnotations() { 601 return sharedGetParameterAnnotations(parameterTypes, parameterAnnotations); 602 } 603 604 @Override 605 void handleParameterNumberMismatch(int resultLength, int numParameters) { 606 throw new AnnotationFormatError("Parameter annotations don't match number of parameters"); 607 } 608 }