/*

  * 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).

  *

  * <p>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

      *     <cite>The Java&trade; Virtual Machine Specification</cite>

      * @since 1.5

      */

     public TypeVariable<Method>[] getTypeParameters() {

         if (getGenericSignature() != null)

             return (TypeVariable<Method>[])getGenericInfo().getTypeParameters();

         else

             return (TypeVariable<Method>[])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.

      *

      * <p>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.

      *

      * <p>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

      *     <cite>The Java&trade; Virtual Machine Specification</cite>

      * @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.

      *

      * <p>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.

      *

      * <p>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

      *     <cite>The Java&trade; Virtual Machine Specification</cite>

      * @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.

      *

      * <p>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

      *     <cite>The Java&trade; Virtual Machine Specification</cite>

      * @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:

      * <pre>

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

      * </pre>

      *

      * <p>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 {

             StringBuilder sb = new StringBuilder();

             int mod = getModifiers() & Modifier.methodModifiers();

             if (mod != 0) {

                 sb.append(Modifier.toString(mod)).append(' ');

             }

             sb.append(Field.getTypeName(getReturnType())).append(' ');

             sb.append(Field.getTypeName(getDeclaringClass())).append('.');

             sb.append(getName()).append('(');

             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

      * "<tt><i>Type</i>[]</tt>", it is denoted as

      * "<tt><i>Type</i>...</tt>".

      *

      * 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.

      *

      * <p>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)).append(' ');

             }

             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()))

                     .append(' ');

             sb.append(Field.getTypeName(getDeclaringClass())).append('.');

             sb.append(getName()).append('(');

             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.

      *

      * <p>If the underlying method is static, then the specified {@code obj}

      * argument is ignored. It may be null.

      *

      * <p>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.

      *

      * <p>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.

      *

      * <p>If the underlying method is static, the class that declared

      * the method is initialized if it has not already been initialized.

      *

      * <p>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 <i>not</i> 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.

      */

     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) {

             ma = acquireMethodAccessor();

         }

         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 MethodAccessor 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;

         } else {

             // Otherwise fabricate one and propagate it up to the root

             tmp = reflectionFactory.newMethodAccessor(this);

             setMethodAccessor(tmp);

         }

         return 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 extends Annotation> T getAnnotation(Class<T> 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<Class<? extends Annotation>, Annotation> declaredAnnotations;

     private synchronized  Map<Class<? extends Annotation>, 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;

     }

 }