/* * Copyright (C) 2014 The Android Open Source Project * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.lang.reflect; import dalvik.annotation.optimization.FastNative; import java.lang.annotation.Annotation; import java.util.Comparator; import libcore.reflect.Types; import libcore.util.EmptyArray; /** * A {@code Method} provides information about, and access to, a single method * on a class or interface. The reflected method may be a class method * or an instance method (including an abstract method). * *

A {@code Method} permits widening conversions to occur when matching the * actual parameters to invoke with the underlying method's formal * parameters, but it throws an {@code IllegalArgumentException} if a * narrowing conversion would occur. * * @see Member * @see java.lang.Class * @see java.lang.Class#getMethods() * @see java.lang.Class#getMethod(String, Class[]) * @see java.lang.Class#getDeclaredMethods() * @see java.lang.Class#getDeclaredMethod(String, Class[]) * * @author Kenneth Russell * @author Nakul Saraiya */ public final class Method extends Executable { /** * Orders methods by their name, parameters and return type. * * @hide */ public static final Comparator ORDER_BY_SIGNATURE = new Comparator() { @Override public int compare(Method a, Method b) { if (a == b) { return 0; } int comparison = a.getName().compareTo(b.getName()); if (comparison == 0) { comparison = a.compareMethodParametersInternal(b); if (comparison == 0) { // This is necessary for methods that have covariant return types. Class aReturnType = a.getReturnType(); Class bReturnType = b.getReturnType(); if (aReturnType == bReturnType) { comparison = 0; } else { comparison = aReturnType.getName().compareTo(bReturnType.getName()); } } } return comparison; } }; private Method() { } @Override boolean hasGenericInformation() { // Android-changed: Signature retrieval is handled in Executable. return super.hasGenericInformationInternal(); } /** * {@inheritDoc} */ @Override public Class getDeclaringClass() { // Android-changed: This is handled by Executable. return super.getDeclaringClassInternal(); } /** * Returns the name of the method represented by this {@code Method} * object, as a {@code String}. */ @Override public String getName() { // Android-changed: This is handled by Executable. return getMethodNameInternal(); } /** * {@inheritDoc} */ @Override public int getModifiers() { // Android-changed: This is handled by Executable. return super.getModifiersInternal(); } /** * {@inheritDoc} * @throws GenericSignatureFormatError {@inheritDoc} * @since 1.5 */ @Override @SuppressWarnings({"rawtypes", "unchecked"}) public TypeVariable[] getTypeParameters() { // Android-changed: This is mostly handled by Executable. GenericInfo info = getMethodOrConstructorGenericInfoInternal(); return (TypeVariable[]) info.formalTypeParameters.clone(); } /** * Returns a {@code Class} object that represents the formal return type * of the method represented by this {@code Method} object. * * @return the return type for the method this object represents */ public Class getReturnType() { return getMethodReturnTypeInternal(); } /** * Returns a {@code Type} object that represents the formal return * type of the method represented by this {@code Method} object. * *

If the return type is a parameterized type, * the {@code Type} object returned must accurately reflect * the actual type parameters used in the source code. * *

If the return type is a type variable or a parameterized type, it * is created. Otherwise, it is resolved. * * @return a {@code Type} object that represents the formal return * type of the underlying method * @throws GenericSignatureFormatError * if the generic method signature does not conform to the format * specified in * The Java™ Virtual Machine Specification * @throws TypeNotPresentException if the underlying method's * return type refers to a non-existent type declaration * @throws MalformedParameterizedTypeException if the * underlying method's return typed refers to a parameterized * type that cannot be instantiated for any reason * @since 1.5 */ public Type getGenericReturnType() { // Android-changed: Modified implementation to use Executable. return Types.getType(getMethodOrConstructorGenericInfoInternal().genericReturnType); } /** * {@inheritDoc} */ @Override public Class[] getParameterTypes() { // Android-changed: This is handled by Executable. Class[] paramTypes = super.getParameterTypesInternal(); if (paramTypes == null) { return EmptyArray.CLASS; } return paramTypes; } /** * {@inheritDoc} * @since 1.8 */ public int getParameterCount() { // Android-changed: This is handled by Executable. return super.getParameterCountInternal(); } /** * {@inheritDoc} * @throws GenericSignatureFormatError {@inheritDoc} * @throws TypeNotPresentException {@inheritDoc} * @throws MalformedParameterizedTypeException {@inheritDoc} * @since 1.5 */ @Override public Type[] getGenericParameterTypes() { return super.getGenericParameterTypes(); } /** * {@inheritDoc} */ @Override @FastNative public native Class[] getExceptionTypes(); /** * {@inheritDoc} * @throws GenericSignatureFormatError {@inheritDoc} * @throws TypeNotPresentException {@inheritDoc} * @throws MalformedParameterizedTypeException {@inheritDoc} * @since 1.5 */ @Override public Type[] getGenericExceptionTypes() { return super.getGenericExceptionTypes(); } /** * Compares this {@code Method} against the specified object. Returns * true if the objects are the same. Two {@code Methods} are the same if * they were declared by the same class and have the same name * and formal parameter types and return type. */ public boolean equals(Object obj) { if (obj != null && obj instanceof Method) { Method other = (Method)obj; if ((getDeclaringClass() == other.getDeclaringClass()) && (getName() == other.getName())) { if (!getReturnType().equals(other.getReturnType())) return false; // Android-changed: Use getParameterTypes. return equalParamTypes(getParameterTypes(), other.getParameterTypes()); } } return false; } /** * Returns a hashcode for this {@code Method}. The hashcode is computed * as the exclusive-or of the hashcodes for the underlying * method's declaring class name and the method's name. */ public int hashCode() { return getDeclaringClass().getName().hashCode() ^ getName().hashCode(); } /** * Returns a string describing this {@code Method}. The string is * formatted as the method access modifiers, if any, followed by * the method return type, followed by a space, followed by the * class declaring the method, followed by a period, followed by * the method name, followed by a parenthesized, comma-separated * list of the method's formal parameter types. If the method * throws checked exceptions, the parameter list is followed by a * space, followed by the word throws followed by a * comma-separated list of the thrown exception types. * For example: * 

     *    public boolean java.lang.Object.equals(java.lang.Object)
     *
* *

The access modifiers are placed in canonical order as * specified by "The Java Language Specification". This is * {@code public}, {@code protected} or {@code private} first, * and then other modifiers in the following order: * {@code abstract}, {@code default}, {@code static}, {@code final}, * {@code synchronized}, {@code native}, {@code strictfp}. * * @return a string describing this {@code Method} * * @jls 8.4.3 Method Modifiers */ public String toString() { // Android-changed: Use getParameterTypes. return sharedToString(Modifier.methodModifiers(), isDefault(), getParameterTypes(), getExceptionTypes()); } @Override void specificToStringHeader(StringBuilder sb) { sb.append(getReturnType().getTypeName()).append(' '); sb.append(getDeclaringClass().getTypeName()).append('.'); sb.append(getName()); } /** * Returns a string describing this {@code Method}, including * type parameters. The string is formatted as the method access * modifiers, if any, followed by an angle-bracketed * comma-separated list of the method's type parameters, if any, * followed by the method's generic return type, followed by a * space, followed by the class declaring the method, followed by * a period, followed by the method name, followed by a * parenthesized, comma-separated list of the method's generic * formal parameter types. * * If this method was declared to take a variable number of * arguments, instead of denoting the last parameter as * "Type[]", it is denoted as * "Type...". * * A space is used to separate access modifiers from one another * and from the type parameters or return type. If there are no * type parameters, the type parameter list is elided; if the type * parameter list is present, a space separates the list from the * class name. If the method is declared to throw exceptions, the * parameter list is followed by a space, followed by the word * throws followed by a comma-separated list of the generic thrown * exception types. * *

The access modifiers are placed in canonical order as * specified by "The Java Language Specification". This is * {@code public}, {@code protected} or {@code private} first, * and then other modifiers in the following order: * {@code abstract}, {@code default}, {@code static}, {@code final}, * {@code synchronized}, {@code native}, {@code strictfp}. * * @return a string describing this {@code Method}, * include type parameters * * @since 1.5 * * @jls 8.4.3 Method Modifiers */ @Override public String toGenericString() { return sharedToGenericString(Modifier.methodModifiers(), isDefault()); } @Override void specificToGenericStringHeader(StringBuilder sb) { Type genRetType = getGenericReturnType(); sb.append(genRetType.getTypeName()).append(' '); sb.append(getDeclaringClass().getTypeName()).append('.'); sb.append(getName()); } /** * Invokes the underlying method represented by this {@code Method} * object, on the specified object with the specified parameters. * Individual parameters are automatically unwrapped to match * primitive formal parameters, and both primitive and reference * parameters are subject to method invocation conversions as * necessary. * *

If the underlying method is static, then the specified {@code obj} * argument is ignored. It may be null. * *

If the number of formal parameters required by the underlying method is * 0, the supplied {@code args} array may be of length 0 or null. * *

If the underlying method is an instance method, it is invoked * using dynamic method lookup as documented in The Java Language * Specification, Second Edition, section 15.12.4.4; in particular, * overriding based on the runtime type of the target object will occur. * *

If the underlying method is static, the class that declared * the method is initialized if it has not already been initialized. * *

If the method completes normally, the value it returns is * returned to the caller of invoke; if the value has a primitive * type, it is first appropriately wrapped in an object. However, * if the value has the type of an array of a primitive type, the * elements of the array are not wrapped in objects; in * other words, an array of primitive type is returned. If the * underlying method return type is void, the invocation returns * null. * * @param obj the object the underlying method is invoked from * @param args the arguments used for the method call * @return the result of dispatching the method represented by * this object on {@code obj} with parameters * {@code args} * * @exception IllegalAccessException if this {@code Method} object * is enforcing Java language access control and the underlying * method is inaccessible. * @exception IllegalArgumentException if the method is an * instance method and the specified object argument * is not an instance of the class or interface * declaring the underlying method (or of a subclass * or implementor thereof); if the number of actual * and formal parameters differ; if an unwrapping * conversion for primitive arguments fails; or if, * after possible unwrapping, a parameter value * cannot be converted to the corresponding formal * parameter type by a method invocation conversion. * @exception InvocationTargetException if the underlying method * throws an exception. * @exception NullPointerException if the specified object is null * and the method is an instance method. * @exception ExceptionInInitializerError if the initialization * provoked by this method fails. */ @FastNative public native Object invoke(Object obj, Object... args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException; /** * Returns {@code true} if this method is a bridge * method; returns {@code false} otherwise. * * @return true if and only if this method is a bridge * method as defined by the Java Language Specification. * @since 1.5 */ public boolean isBridge() { // Android-changed: This is handled by Executable. return super.isBridgeMethodInternal(); } /** * {@inheritDoc} * @since 1.5 */ @Override public boolean isVarArgs() { return super.isVarArgs(); } /** * {@inheritDoc} * @jls 13.1 The Form of a Binary * @since 1.5 */ @Override public boolean isSynthetic() { return super.isSynthetic(); } /** * Returns {@code true} if this method is a default * method; returns {@code false} otherwise. * * A default method is a public non-abstract instance method, that * is, a non-static method with a body, declared in an interface * type. * * @return true if and only if this method is a default * method as defined by the Java Language Specification. * @since 1.8 */ public boolean isDefault() { // Android-changed: This is handled by Executable. return super.isDefaultMethodInternal(); } /** * Returns the default value for the annotation member represented by * this {@code Method} instance. If the member is of a primitive type, * an instance of the corresponding wrapper type is returned. Returns * null if no default is associated with the member, or if the method * instance does not represent a declared member of an annotation type. * * @return the default value for the annotation member represented * by this {@code Method} instance. * @throws TypeNotPresentException if the annotation is of type * {@link Class} and no definition can be found for the * default class value. * @since 1.5 */ @FastNative public native Object getDefaultValue(); /** * {@inheritDoc} * @throws NullPointerException {@inheritDoc} * @since 1.5 */ public T getAnnotation(Class annotationClass) { return super.getAnnotation(annotationClass); } /** * {@inheritDoc} * @since 1.5 */ public Annotation[] getDeclaredAnnotations() { return super.getDeclaredAnnotations(); } /** * {@inheritDoc} * @since 1.5 */ @Override public Annotation[][] getParameterAnnotations() { // Android-changed: This is handled by Executable. return super.getParameterAnnotationsInternal(); } /** * Returns true if this and {@code method} have the same name and the same * parameters in the same order. Such methods can share implementation if * one method's return types is assignable to the other. * * @hide needed by Proxy */ boolean equalNameAndParameters(Method m) { return equalNameAndParametersInternal(m); } }