/* * Copyright (c) 1996, 2006, 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 sun.reflect.MethodAccessor; import sun.reflect.Reflection; import sun.reflect.generics.repository.MethodRepository; import sun.reflect.generics.factory.CoreReflectionFactory; import sun.reflect.generics.factory.GenericsFactory; import sun.reflect.generics.scope.MethodScope; import sun.reflect.annotation.AnnotationType; import sun.reflect.annotation.AnnotationParser; import java.lang.annotation.Annotation; import java.lang.annotation.AnnotationFormatError; import java.nio.ByteBuffer; import java.util.Map; /** * 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 AccessibleObject implements GenericDeclaration, Member { private Class clazz; private int slot; // This is guaranteed to be interned by the VM in the 1.4 // reflection implementation private String name; private Class returnType; private Class[] parameterTypes; private Class[] exceptionTypes; private int modifiers; // Generics and annotations support private transient String signature; // generic info repository; lazily initialized private transient MethodRepository genericInfo; private byte[] annotations; private byte[] parameterAnnotations; private byte[] annotationDefault; private volatile MethodAccessor methodAccessor; // For sharing of MethodAccessors. This branching structure is // currently only two levels deep (i.e., one root Method and // potentially many Method objects pointing to it.) private Method root; // Generics infrastructure private String getGenericSignature() {return signature;} // Accessor for factory private GenericsFactory getFactory() { // create scope and factory return CoreReflectionFactory.make(this, MethodScope.make(this)); } // Accessor for generic info repository private MethodRepository getGenericInfo() { // lazily initialize repository if necessary if (genericInfo == null) { // create and cache generic info repository genericInfo = MethodRepository.make(getGenericSignature(), getFactory()); } return genericInfo; //return cached repository } /** * Package-private constructor used by ReflectAccess to enable * instantiation of these objects in Java code from the java.lang * package via sun.reflect.LangReflectAccess. */ Method(Class declaringClass, String name, Class[] parameterTypes, Class returnType, Class[] checkedExceptions, int modifiers, int slot, String signature, byte[] annotations, byte[] parameterAnnotations, byte[] annotationDefault) { this.clazz = declaringClass; this.name = name; this.parameterTypes = parameterTypes; this.returnType = returnType; this.exceptionTypes = checkedExceptions; this.modifiers = modifiers; this.slot = slot; this.signature = signature; this.annotations = annotations; this.parameterAnnotations = parameterAnnotations; this.annotationDefault = annotationDefault; } /** * Package-private routine (exposed to java.lang.Class via * ReflectAccess) which returns a copy of this Method. The copy's * "root" field points to this Method. */ Method copy() { // This routine enables sharing of MethodAccessor objects // among Method objects which refer to the same underlying // method in the VM. (All of this contortion is only necessary // because of the "accessibility" bit in AccessibleObject, // which implicitly requires that new java.lang.reflect // objects be fabricated for each reflective call on Class // objects.) Method res = new Method(clazz, name, parameterTypes, returnType, exceptionTypes, modifiers, slot, signature, annotations, parameterAnnotations, annotationDefault); res.root = this; // Might as well eagerly propagate this if already present res.methodAccessor = methodAccessor; return res; } /** * Returns the {@code Class} object representing the class or interface * that declares the method represented by this {@code Method} object. */ public Class getDeclaringClass() { return clazz; } /** * Returns the name of the method represented by this {@code Method} * object, as a {@code String}. */ public String getName() { return name; } /** * Returns the Java language modifiers for the method represented * by this {@code Method} object, as an integer. The {@code Modifier} class should * be used to decode the modifiers. * * @see Modifier */ public int getModifiers() { return modifiers; } /** * Returns an array of {@code TypeVariable} objects that represent the * type variables declared by the generic declaration represented by this * {@code GenericDeclaration} object, in declaration order. Returns an * array of length 0 if the underlying generic declaration declares no type * variables. * * @return an array of {@code TypeVariable} objects that represent * the type variables declared by this generic declaration * @throws GenericSignatureFormatError if the generic * signature of this generic declaration does not conform to * the format specified in the Java Virtual Machine Specification, * 3rd edition * @since 1.5 */ public TypeVariable[] getTypeParameters() { if (getGenericSignature() != null) return (TypeVariable[])getGenericInfo().getTypeParameters(); else return (TypeVariable[])new TypeVariable[0]; } /** * 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 returnType; } /** * 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, 3rd edition * @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() { if (getGenericSignature() != null) { return getGenericInfo().getReturnType(); } else { return getReturnType();} } /** * Returns an array of {@code Class} objects that represent the formal * parameter types, in declaration order, of the method * represented by this {@code Method} object. Returns an array of length * 0 if the underlying method takes no parameters. * * @return the parameter types for the method this object * represents */ public Class[] getParameterTypes() { return (Class[]) parameterTypes.clone(); } /** * Returns an array of {@code Type} objects that represent the formal * parameter types, in declaration order, of the method represented by * this {@code Method} object. Returns an array of length 0 if the * underlying method takes no parameters. * *

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

If a formal parameter type is a type variable or a parameterized * type, it is created. Otherwise, it is resolved. * * @return an array of Types that represent the formal * parameter types of the underlying method, in declaration order * @throws GenericSignatureFormatError * if the generic method signature does not conform to the format * specified in the Java Virtual Machine Specification, 3rd edition * @throws TypeNotPresentException if any of the parameter * types of the underlying method refers to a non-existent type * declaration * @throws MalformedParameterizedTypeException if any of * the underlying method's parameter types refer to a parameterized * type that cannot be instantiated for any reason * @since 1.5 */ public Type[] getGenericParameterTypes() { if (getGenericSignature() != null) return getGenericInfo().getParameterTypes(); else return getParameterTypes(); } /** * Returns an array of {@code Class} objects that represent * the types of the exceptions declared to be thrown * by the underlying method * represented by this {@code Method} object. Returns an array of length * 0 if the method declares no exceptions in its {@code throws} clause. * * @return the exception types declared as being thrown by the * method this object represents */ public Class[] getExceptionTypes() { return (Class[]) exceptionTypes.clone(); } /** * Returns an array of {@code Type} objects that represent the * exceptions declared to be thrown by this {@code Method} object. * Returns an array of length 0 if the underlying method declares * no exceptions in its {@code throws} clause. * *

If an exception type is a type variable or a parameterized * type, it is created. Otherwise, it is resolved. * * @return an array of Types that represent the exception types * thrown by the underlying method * @throws GenericSignatureFormatError * if the generic method signature does not conform to the format * specified in the Java Virtual Machine Specification, 3rd edition * @throws TypeNotPresentException if the underlying method's * {@code throws} clause refers to a non-existent type declaration * @throws MalformedParameterizedTypeException if * the underlying method's {@code throws} clause refers to a * parameterized type that cannot be instantiated for any reason * @since 1.5 */ public Type[] getGenericExceptionTypes() { Type[] result; if (getGenericSignature() != null && ((result = getGenericInfo().getExceptionTypes()).length > 0)) return result; else return getExceptionTypes(); } /** * 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 (!returnType.equals(other.getReturnType())) return false; /* Avoid unnecessary cloning */ Class[] params1 = parameterTypes; Class[] params2 = other.parameterTypes; if (params1.length == params2.length) { for (int i = 0; i < params1.length; i++) { if (params1[i] != params2[i]) return false; } return true; } } } 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 static}, {@code final}, * {@code synchronized}, {@code native}, {@code strictfp}. */ public String toString() { try { StringBuffer sb = new StringBuffer(); int mod = getModifiers() & Modifier.methodModifiers(); if (mod != 0) { sb.append(Modifier.toString(mod) + " "); } sb.append(Field.getTypeName(getReturnType()) + " "); sb.append(Field.getTypeName(getDeclaringClass()) + "."); sb.append(getName() + "("); Class[] params = parameterTypes; // avoid clone for (int j = 0; j < params.length; j++) { sb.append(Field.getTypeName(params[j])); if (j < (params.length - 1)) sb.append(","); } sb.append(")"); Class[] exceptions = exceptionTypes; // avoid clone if (exceptions.length > 0) { sb.append(" throws "); for (int k = 0; k < exceptions.length; k++) { sb.append(exceptions[k].getName()); if (k < (exceptions.length - 1)) sb.append(","); } } return sb.toString(); } catch (Exception e) { return "<" + e + ">"; } } /** * 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. If there are no type parameters, the type * parameter list is elided. * *

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 static}, {@code final}, * {@code synchronized}, {@code native}, {@code strictfp}. * * @return a string describing this {@code Method}, * include type parameters * * @since 1.5 */ public String toGenericString() { try { StringBuilder sb = new StringBuilder(); int mod = getModifiers() & Modifier.methodModifiers(); if (mod != 0) { sb.append(Modifier.toString(mod) + " "); } TypeVariable[] typeparms = getTypeParameters(); if (typeparms.length > 0) { boolean first = true; sb.append("<"); for(TypeVariable typeparm: typeparms) { if (!first) sb.append(","); // Class objects can't occur here; no need to test // and call Class.getName(). sb.append(typeparm.toString()); first = false; } sb.append("> "); } Type genRetType = getGenericReturnType(); sb.append( ((genRetType instanceof Class)? Field.getTypeName((Class)genRetType):genRetType.toString()) + " "); sb.append(Field.getTypeName(getDeclaringClass()) + "."); sb.append(getName() + "("); Type[] params = getGenericParameterTypes(); for (int j = 0; j < params.length; j++) { String param = (params[j] instanceof Class)? Field.getTypeName((Class)params[j]): (params[j].toString()); if (isVarArgs() && (j == params.length - 1)) // replace T[] with T... param = param.replaceFirst("\\[\\]$", "..."); sb.append(param); if (j < (params.length - 1)) sb.append(","); } sb.append(")"); Type[] exceptions = getGenericExceptionTypes(); if (exceptions.length > 0) { sb.append(" throws "); for (int k = 0; k < exceptions.length; k++) { sb.append((exceptions[k] instanceof Class)? ((Class)exceptions[k]).getName(): exceptions[k].toString()); if (k < (exceptions.length - 1)) sb.append(","); } } return sb.toString(); } catch (Exception e) { return "<" + e + ">"; } } /** * 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 * enforces 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. */ public Object invoke(Object obj, Object... args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException { if (!override) { if (!Reflection.quickCheckMemberAccess(clazz, modifiers)) { Class caller = Reflection.getCallerClass(1); checkAccess(caller, clazz, obj, modifiers); } } MethodAccessor ma = methodAccessor; // read volatile if (ma == null) { acquireMethodAccessor(); ma = methodAccessor; // read volatile } return ma.invoke(obj, args); } /** * 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() { return (getModifiers() & Modifier.BRIDGE) != 0; } /** * Returns {@code true} if this method was declared to take * a variable number of arguments; returns {@code false} * otherwise. * * @return {@code true} if an only if this method was declared to * take a variable number of arguments. * @since 1.5 */ public boolean isVarArgs() { return (getModifiers() & Modifier.VARARGS) != 0; } /** * Returns {@code true} if this method is a synthetic * method; returns {@code false} otherwise. * * @return true if and only if this method is a synthetic * method as defined by the Java Language Specification. * @since 1.5 */ public boolean isSynthetic() { return Modifier.isSynthetic(getModifiers()); } // NOTE that there is no synchronization used here. It is correct // (though not efficient) to generate more than one MethodAccessor // for a given Method. However, avoiding synchronization will // probably make the implementation more scalable. private void acquireMethodAccessor() { // First check to see if one has been created yet, and take it // if so MethodAccessor tmp = null; if (root != null) tmp = root.getMethodAccessor(); if (tmp != null) { methodAccessor = tmp; return; } // Otherwise fabricate one and propagate it up to the root tmp = reflectionFactory.newMethodAccessor(this); setMethodAccessor(tmp); } // Returns MethodAccessor for this Method object, not looking up // the chain to the root MethodAccessor getMethodAccessor() { return methodAccessor; } // Sets the MethodAccessor for this Method object and // (recursively) its root void setMethodAccessor(MethodAccessor accessor) { methodAccessor = accessor; // Propagate up if (root != null) { root.setMethodAccessor(accessor); } } /** * @throws NullPointerException {@inheritDoc} * @since 1.5 */ public T getAnnotation(Class annotationClass) { if (annotationClass == null) throw new NullPointerException(); return (T) declaredAnnotations().get(annotationClass); } /** * @since 1.5 */ public Annotation[] getDeclaredAnnotations() { return AnnotationParser.toArray(declaredAnnotations()); } private transient Map, Annotation> declaredAnnotations; private synchronized Map, Annotation> declaredAnnotations() { if (declaredAnnotations == null) { declaredAnnotations = AnnotationParser.parseAnnotations( annotations, sun.misc.SharedSecrets.getJavaLangAccess(). getConstantPool(getDeclaringClass()), getDeclaringClass()); } return declaredAnnotations; } /** * 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 */ public Object getDefaultValue() { if (annotationDefault == null) return null; Class memberType = AnnotationType.invocationHandlerReturnType( getReturnType()); Object result = AnnotationParser.parseMemberValue( memberType, ByteBuffer.wrap(annotationDefault), sun.misc.SharedSecrets.getJavaLangAccess(). getConstantPool(getDeclaringClass()), getDeclaringClass()); if (result instanceof sun.reflect.annotation.ExceptionProxy) throw new AnnotationFormatError("Invalid default: " + this); return result; } /** * Returns an array of arrays that represent the annotations on the formal * parameters, in declaration order, of the method represented by * this {@code Method} object. (Returns an array of length zero if the * underlying method is parameterless. If the method has one or more * parameters, a nested array of length zero is returned for each parameter * with no annotations.) The annotation objects contained in the returned * arrays are serializable. The caller of this method is free to modify * the returned arrays; it will have no effect on the arrays returned to * other callers. * * @return an array of arrays that represent the annotations on the formal * parameters, in declaration order, of the method represented by this * Method object * @since 1.5 */ public Annotation[][] getParameterAnnotations() { int numParameters = parameterTypes.length; if (parameterAnnotations == null) return new Annotation[numParameters][0]; Annotation[][] result = AnnotationParser.parseParameterAnnotations( parameterAnnotations, sun.misc.SharedSecrets.getJavaLangAccess(). getConstantPool(getDeclaringClass()), getDeclaringClass()); if (result.length != numParameters) throw new java.lang.annotation.AnnotationFormatError( "Parameter annotations don't match number of parameters"); return result; } }