1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. Oracle designates this 9 * particular file as subject to the "Classpath" exception as provided 10 * by Oracle in the LICENSE file that accompanied this code. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 23 * or visit www.oracle.com if you need additional information or have any 24 * questions. 25 */ 26 27 package java.lang.reflect; 28 29 import dalvik.annotation.optimization.FastNative; 30 import java.lang.annotation.Annotation; 31 import java.util.Comparator; 32 import libcore.reflect.Types; 33 import libcore.util.EmptyArray; 34 35 /** 36 * A {@code Method} provides information about, and access to, a single method 37 * on a class or interface. The reflected method may be a class method 38 * or an instance method (including an abstract method). 39 * 40 * <p>A {@code Method} permits widening conversions to occur when matching the 41 * actual parameters to invoke with the underlying method's formal 42 * parameters, but it throws an {@code IllegalArgumentException} if a 43 * narrowing conversion would occur. 44 * 45 * @see Member 46 * @see java.lang.Class 47 * @see java.lang.Class#getMethods() 48 * @see java.lang.Class#getMethod(String, Class[]) 49 * @see java.lang.Class#getDeclaredMethods() 50 * @see java.lang.Class#getDeclaredMethod(String, Class[]) 51 * 52 * @author Kenneth Russell 53 * @author Nakul Saraiya 54 */ 55 public final class Method extends Executable { 56 /** 57 * Orders methods by their name, parameters and return type. 58 * 59 * @hide 60 */ 61 public static final Comparator<Method> ORDER_BY_SIGNATURE = new Comparator<Method>() { 62 @Override public int compare(Method a, Method b) { 63 if (a == b) { 64 return 0; 65 } 66 int comparison = a.getName().compareTo(b.getName()); 67 if (comparison == 0) { 68 comparison = a.compareMethodParametersInternal(b); 69 if (comparison == 0) { 70 // This is necessary for methods that have covariant return types. 71 Class<?> aReturnType = a.getReturnType(); 72 Class<?> bReturnType = b.getReturnType(); 73 if (aReturnType == bReturnType) { 74 comparison = 0; 75 } else { 76 comparison = aReturnType.getName().compareTo(bReturnType.getName()); 77 } 78 } 79 } 80 return comparison; 81 } 82 }; 83 Method()84 private Method() { 85 } 86 87 @Override hasGenericInformation()88 boolean hasGenericInformation() { 89 // Android-changed: Signature retrieval is handled in Executable. 90 return super.hasGenericInformationInternal(); 91 } 92 93 /** 94 * {@inheritDoc} 95 */ 96 @Override getDeclaringClass()97 public Class<?> getDeclaringClass() { 98 // Android-changed: This is handled by Executable. 99 return super.getDeclaringClassInternal(); 100 } 101 102 /** 103 * Returns the name of the method represented by this {@code Method} 104 * object, as a {@code String}. 105 */ 106 @Override getName()107 public String getName() { 108 // Android-changed: This is handled by Executable. 109 return getMethodNameInternal(); 110 } 111 112 /** 113 * {@inheritDoc} 114 */ 115 @Override getModifiers()116 public int getModifiers() { 117 // Android-changed: This is handled by Executable. 118 return super.getModifiersInternal(); 119 } 120 121 /** 122 * {@inheritDoc} 123 * @throws GenericSignatureFormatError {@inheritDoc} 124 * @since 1.5 125 */ 126 @Override 127 @SuppressWarnings({"rawtypes", "unchecked"}) getTypeParameters()128 public TypeVariable<Method>[] getTypeParameters() { 129 // Android-changed: This is mostly handled by Executable. 130 GenericInfo info = getMethodOrConstructorGenericInfoInternal(); 131 return (TypeVariable<Method>[]) info.formalTypeParameters.clone(); 132 } 133 134 /** 135 * Returns a {@code Class} object that represents the formal return type 136 * of the method represented by this {@code Method} object. 137 * 138 * @return the return type for the method this object represents 139 */ getReturnType()140 public Class<?> getReturnType() { 141 return getMethodReturnTypeInternal(); 142 } 143 144 /** 145 * Returns a {@code Type} object that represents the formal return 146 * type of the method represented by this {@code Method} object. 147 * 148 * <p>If the return type is a parameterized type, 149 * the {@code Type} object returned must accurately reflect 150 * the actual type parameters used in the source code. 151 * 152 * <p>If the return type is a type variable or a parameterized type, it 153 * is created. Otherwise, it is resolved. 154 * 155 * @return a {@code Type} object that represents the formal return 156 * type of the underlying method 157 * @throws GenericSignatureFormatError 158 * if the generic method signature does not conform to the format 159 * specified in 160 * <cite>The Java™ Virtual Machine Specification</cite> 161 * @throws TypeNotPresentException if the underlying method's 162 * return type refers to a non-existent type declaration 163 * @throws MalformedParameterizedTypeException if the 164 * underlying method's return typed refers to a parameterized 165 * type that cannot be instantiated for any reason 166 * @since 1.5 167 */ getGenericReturnType()168 public Type getGenericReturnType() { 169 // Android-changed: Modified implementation to use Executable. 170 return Types.getType(getMethodOrConstructorGenericInfoInternal().genericReturnType); 171 } 172 173 /** 174 * {@inheritDoc} 175 */ 176 @Override getParameterTypes()177 public Class<?>[] getParameterTypes() { 178 // Android-changed: This is handled by Executable. 179 Class<?>[] paramTypes = super.getParameterTypesInternal(); 180 if (paramTypes == null) { 181 return EmptyArray.CLASS; 182 } 183 184 return paramTypes; 185 } 186 187 /** 188 * {@inheritDoc} 189 * @since 1.8 190 */ getParameterCount()191 public int getParameterCount() { 192 // Android-changed: This is handled by Executable. 193 return super.getParameterCountInternal(); 194 } 195 196 /** 197 * {@inheritDoc} 198 * @throws GenericSignatureFormatError {@inheritDoc} 199 * @throws TypeNotPresentException {@inheritDoc} 200 * @throws MalformedParameterizedTypeException {@inheritDoc} 201 * @since 1.5 202 */ 203 @Override getGenericParameterTypes()204 public Type[] getGenericParameterTypes() { 205 return super.getGenericParameterTypes(); 206 } 207 208 /** 209 * {@inheritDoc} 210 */ 211 @Override 212 @FastNative getExceptionTypes()213 public native Class<?>[] getExceptionTypes(); 214 215 /** 216 * {@inheritDoc} 217 * @throws GenericSignatureFormatError {@inheritDoc} 218 * @throws TypeNotPresentException {@inheritDoc} 219 * @throws MalformedParameterizedTypeException {@inheritDoc} 220 * @since 1.5 221 */ 222 @Override getGenericExceptionTypes()223 public Type[] getGenericExceptionTypes() { 224 return super.getGenericExceptionTypes(); 225 } 226 227 /** 228 * Compares this {@code Method} against the specified object. Returns 229 * true if the objects are the same. Two {@code Methods} are the same if 230 * they were declared by the same class and have the same name 231 * and formal parameter types and return type. 232 */ equals(Object obj)233 public boolean equals(Object obj) { 234 if (obj != null && obj instanceof Method) { 235 Method other = (Method)obj; 236 if ((getDeclaringClass() == other.getDeclaringClass()) 237 && (getName() == other.getName())) { 238 if (!getReturnType().equals(other.getReturnType())) 239 return false; 240 // Android-changed: Use getParameterTypes. 241 return equalParamTypes(getParameterTypes(), other.getParameterTypes()); 242 } 243 } 244 return false; 245 } 246 247 /** 248 * Returns a hashcode for this {@code Method}. The hashcode is computed 249 * as the exclusive-or of the hashcodes for the underlying 250 * method's declaring class name and the method's name. 251 */ hashCode()252 public int hashCode() { 253 return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); 254 } 255 256 /** 257 * Returns a string describing this {@code Method}. The string is 258 * formatted as the method access modifiers, if any, followed by 259 * the method return type, followed by a space, followed by the 260 * class declaring the method, followed by a period, followed by 261 * the method name, followed by a parenthesized, comma-separated 262 * list of the method's formal parameter types. If the method 263 * throws checked exceptions, the parameter list is followed by a 264 * space, followed by the word throws followed by a 265 * comma-separated list of the thrown exception types. 266 * For example: 267 * <pre> 268 * public boolean java.lang.Object.equals(java.lang.Object) 269 * </pre> 270 * 271 * <p>The access modifiers are placed in canonical order as 272 * specified by "The Java Language Specification". This is 273 * {@code public}, {@code protected} or {@code private} first, 274 * and then other modifiers in the following order: 275 * {@code abstract}, {@code default}, {@code static}, {@code final}, 276 * {@code synchronized}, {@code native}, {@code strictfp}. 277 * 278 * @return a string describing this {@code Method} 279 * 280 * @jls 8.4.3 Method Modifiers 281 */ toString()282 public String toString() { 283 // Android-changed: Use getParameterTypes. 284 return sharedToString(Modifier.methodModifiers(), 285 isDefault(), 286 getParameterTypes(), 287 getExceptionTypes()); 288 } 289 290 @Override specificToStringHeader(StringBuilder sb)291 void specificToStringHeader(StringBuilder sb) { 292 sb.append(getReturnType().getTypeName()).append(' '); 293 sb.append(getDeclaringClass().getTypeName()).append('.'); 294 sb.append(getName()); 295 } 296 297 /** 298 * Returns a string describing this {@code Method}, including 299 * type parameters. The string is formatted as the method access 300 * modifiers, if any, followed by an angle-bracketed 301 * comma-separated list of the method's type parameters, if any, 302 * followed by the method's generic return type, followed by a 303 * space, followed by the class declaring the method, followed by 304 * a period, followed by the method name, followed by a 305 * parenthesized, comma-separated list of the method's generic 306 * formal parameter types. 307 * 308 * If this method was declared to take a variable number of 309 * arguments, instead of denoting the last parameter as 310 * "<tt><i>Type</i>[]</tt>", it is denoted as 311 * "<tt><i>Type</i>...</tt>". 312 * 313 * A space is used to separate access modifiers from one another 314 * and from the type parameters or return type. If there are no 315 * type parameters, the type parameter list is elided; if the type 316 * parameter list is present, a space separates the list from the 317 * class name. If the method is declared to throw exceptions, the 318 * parameter list is followed by a space, followed by the word 319 * throws followed by a comma-separated list of the generic thrown 320 * exception types. 321 * 322 * <p>The access modifiers are placed in canonical order as 323 * specified by "The Java Language Specification". This is 324 * {@code public}, {@code protected} or {@code private} first, 325 * and then other modifiers in the following order: 326 * {@code abstract}, {@code default}, {@code static}, {@code final}, 327 * {@code synchronized}, {@code native}, {@code strictfp}. 328 * 329 * @return a string describing this {@code Method}, 330 * include type parameters 331 * 332 * @since 1.5 333 * 334 * @jls 8.4.3 Method Modifiers 335 */ 336 @Override toGenericString()337 public String toGenericString() { 338 return sharedToGenericString(Modifier.methodModifiers(), isDefault()); 339 } 340 341 @Override specificToGenericStringHeader(StringBuilder sb)342 void specificToGenericStringHeader(StringBuilder sb) { 343 Type genRetType = getGenericReturnType(); 344 sb.append(genRetType.getTypeName()).append(' '); 345 sb.append(getDeclaringClass().getTypeName()).append('.'); 346 sb.append(getName()); 347 } 348 349 /** 350 * Invokes the underlying method represented by this {@code Method} 351 * object, on the specified object with the specified parameters. 352 * Individual parameters are automatically unwrapped to match 353 * primitive formal parameters, and both primitive and reference 354 * parameters are subject to method invocation conversions as 355 * necessary. 356 * 357 * <p>If the underlying method is static, then the specified {@code obj} 358 * argument is ignored. It may be null. 359 * 360 * <p>If the number of formal parameters required by the underlying method is 361 * 0, the supplied {@code args} array may be of length 0 or null. 362 * 363 * <p>If the underlying method is an instance method, it is invoked 364 * using dynamic method lookup as documented in The Java Language 365 * Specification, Second Edition, section 15.12.4.4; in particular, 366 * overriding based on the runtime type of the target object will occur. 367 * 368 * <p>If the underlying method is static, the class that declared 369 * the method is initialized if it has not already been initialized. 370 * 371 * <p>If the method completes normally, the value it returns is 372 * returned to the caller of invoke; if the value has a primitive 373 * type, it is first appropriately wrapped in an object. However, 374 * if the value has the type of an array of a primitive type, the 375 * elements of the array are <i>not</i> wrapped in objects; in 376 * other words, an array of primitive type is returned. If the 377 * underlying method return type is void, the invocation returns 378 * null. 379 * 380 * @param obj the object the underlying method is invoked from 381 * @param args the arguments used for the method call 382 * @return the result of dispatching the method represented by 383 * this object on {@code obj} with parameters 384 * {@code args} 385 * 386 * @exception IllegalAccessException if this {@code Method} object 387 * is enforcing Java language access control and the underlying 388 * method is inaccessible. 389 * @exception IllegalArgumentException if the method is an 390 * instance method and the specified object argument 391 * is not an instance of the class or interface 392 * declaring the underlying method (or of a subclass 393 * or implementor thereof); if the number of actual 394 * and formal parameters differ; if an unwrapping 395 * conversion for primitive arguments fails; or if, 396 * after possible unwrapping, a parameter value 397 * cannot be converted to the corresponding formal 398 * parameter type by a method invocation conversion. 399 * @exception InvocationTargetException if the underlying method 400 * throws an exception. 401 * @exception NullPointerException if the specified object is null 402 * and the method is an instance method. 403 * @exception ExceptionInInitializerError if the initialization 404 * provoked by this method fails. 405 */ 406 @FastNative invoke(Object obj, Object... args)407 public native Object invoke(Object obj, Object... args) 408 throws IllegalAccessException, IllegalArgumentException, InvocationTargetException; 409 410 /** 411 * Returns {@code true} if this method is a bridge 412 * method; returns {@code false} otherwise. 413 * 414 * @return true if and only if this method is a bridge 415 * method as defined by the Java Language Specification. 416 * @since 1.5 417 */ isBridge()418 public boolean isBridge() { 419 // Android-changed: This is handled by Executable. 420 return super.isBridgeMethodInternal(); 421 } 422 423 /** 424 * {@inheritDoc} 425 * @since 1.5 426 */ 427 @Override isVarArgs()428 public boolean isVarArgs() { 429 return super.isVarArgs(); 430 } 431 432 /** 433 * {@inheritDoc} 434 * @jls 13.1 The Form of a Binary 435 * @since 1.5 436 */ 437 @Override isSynthetic()438 public boolean isSynthetic() { 439 return super.isSynthetic(); 440 } 441 442 /** 443 * Returns {@code true} if this method is a default 444 * method; returns {@code false} otherwise. 445 * 446 * A default method is a public non-abstract instance method, that 447 * is, a non-static method with a body, declared in an interface 448 * type. 449 * 450 * @return true if and only if this method is a default 451 * method as defined by the Java Language Specification. 452 * @since 1.8 453 */ isDefault()454 public boolean isDefault() { 455 // Android-changed: This is handled by Executable. 456 return super.isDefaultMethodInternal(); 457 } 458 459 /** 460 * Returns the default value for the annotation member represented by 461 * this {@code Method} instance. If the member is of a primitive type, 462 * an instance of the corresponding wrapper type is returned. Returns 463 * null if no default is associated with the member, or if the method 464 * instance does not represent a declared member of an annotation type. 465 * 466 * @return the default value for the annotation member represented 467 * by this {@code Method} instance. 468 * @throws TypeNotPresentException if the annotation is of type 469 * {@link Class} and no definition can be found for the 470 * default class value. 471 * @since 1.5 472 */ 473 @FastNative getDefaultValue()474 public native Object getDefaultValue(); 475 476 /** 477 * {@inheritDoc} 478 * @throws NullPointerException {@inheritDoc} 479 * @since 1.5 480 */ getAnnotation(Class<T> annotationClass)481 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) { 482 return super.getAnnotation(annotationClass); 483 } 484 485 /** 486 * {@inheritDoc} 487 * @since 1.5 488 */ getDeclaredAnnotations()489 public Annotation[] getDeclaredAnnotations() { 490 return super.getDeclaredAnnotations(); 491 } 492 493 /** 494 * {@inheritDoc} 495 * @since 1.5 496 */ 497 @Override getParameterAnnotations()498 public Annotation[][] getParameterAnnotations() { 499 // Android-changed: This is handled by Executable. 500 return super.getParameterAnnotationsInternal(); 501 } 502 503 /** 504 * Returns true if this and {@code method} have the same name and the same 505 * parameters in the same order. Such methods can share implementation if 506 * one method's return types is assignable to the other. 507 * 508 * @hide needed by Proxy 509 */ equalNameAndParameters(Method m)510 boolean equalNameAndParameters(Method m) { 511 return equalNameAndParametersInternal(m); 512 } 513 } 514