/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.beanutils;


import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.Map;
import java.util.WeakHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


 Utility reflection methods focused on methods in general rather than properties in particular. 
Known Limitations
Accessing Public Methods In A Default Access Superclass
There is an issue when invoking public methods contained in a default access superclass.
Reflection locates these methods fine and correctly assigns them as public.
However, an IllegalAccessException is thrown if the method is invoked.
MethodUtils contains a workaround for this situation.
It will attempt to call setAccessible on this method.
If this call succeeds, then the method can be invoked as normal.
This call will only succeed when the application has sufficient security privilages.
If this call fails then a warning will be logged and the method may fail.
Version:
$Id$/**
 * <p> Utility reflection methods focused on methods in general rather than properties in particular. </p>
 *
 * <h3>Known Limitations</h3>
 * <h4>Accessing Public Methods In A Default Access Superclass</h4>
 * <p>There is an issue when invoking public methods contained in a default access superclass.
 * Reflection locates these methods fine and correctly assigns them as public.
 * However, an <code>IllegalAccessException</code> is thrown if the method is invoked.</p>
 *
 * <p><code>MethodUtils</code> contains a workaround for this situation.
 * It will attempt to call <code>setAccessible</code> on this method.
 * If this call succeeds, then the method can be invoked as normal.
 * This call will only succeed when the application has sufficient security privilages.
 * If this call fails then a warning will be logged and the method may fail.</p>
 *
 * @version $Id$
 */

public class MethodUtils {

    // --------------------------------------------------------- Private Methods

    
Only log warning about accessibility work around once.

Note that this is broken when this class is deployed via a shared
classloader in a container, as the warning message will be emitted
only once, not once per webapp. However making the warning appear
once per webapp means having a map keyed by context classloader
which introduces nasty memory-leak problems. As this warning is
really optional we can ignore this problem; only one of the webapps
will get the warning in its logs but that should be good enough.
/**
     * Only log warning about accessibility work around once.
     * <p>
     * Note that this is broken when this class is deployed via a shared
     * classloader in a container, as the warning message will be emitted
     * only once, not once per webapp. However making the warning appear
     * once per webapp means having a map keyed by context classloader
     * which introduces nasty memory-leak problems. As this warning is
     * really optional we can ignore this problem; only one of the webapps
     * will get the warning in its logs but that should be good enough.
     */
    private static boolean loggedAccessibleWarning = false;

    
Indicates whether methods should be cached for improved performance.

Note that when this class is deployed via a shared classloader in
a container, this will affect all webapps. However making this
configurable per webapp would mean having a map keyed by context classloader
which may introduce memory-leak problems.
/**
     * Indicates whether methods should be cached for improved performance.
     * <p>
     * Note that when this class is deployed via a shared classloader in
     * a container, this will affect all webapps. However making this
     * configurable per webapp would mean having a map keyed by context classloader
     * which may introduce memory-leak problems.
     */
    private static boolean CACHE_METHODS = true;

    
An empty class array /** An empty class array */
    private static final Class<?>[] EMPTY_CLASS_PARAMETERS = new Class[0];
    
An empty object array /** An empty object array */
    private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];

    
Stores a cache of MethodDescriptor -> Method in a WeakHashMap.

The keys into this map only ever exist as temporary variables within
methods of this class, and are never exposed to users of this class.
This means that the WeakHashMap is used only as a mechanism for
limiting the size of the cache, ie a way to tell the garbage collector
that the contents of the cache can be completely garbage-collected
whenever it needs the memory. Whether this is a good approach to
this problem is doubtful; something like the commons-collections
LRUMap may be more appropriate (though of course selecting an
appropriate size is an issue).

This static variable is safe even when this code is deployed via a
shared classloader because it is keyed via a MethodDescriptor object
which has a Class as one of its members and that member is used in
the MethodDescriptor.equals method. So two components that load the same
class via different classloaders will generate non-equal MethodDescriptor
objects and hence end up with different entries in the map.
/**
     * Stores a cache of MethodDescriptor -> Method in a WeakHashMap.
     * <p>
     * The keys into this map only ever exist as temporary variables within
     * methods of this class, and are never exposed to users of this class.
     * This means that the WeakHashMap is used only as a mechanism for
     * limiting the size of the cache, ie a way to tell the garbage collector
     * that the contents of the cache can be completely garbage-collected
     * whenever it needs the memory. Whether this is a good approach to
     * this problem is doubtful; something like the commons-collections
     * LRUMap may be more appropriate (though of course selecting an
     * appropriate size is an issue).
     * <p>
     * This static variable is safe even when this code is deployed via a
     * shared classloader because it is keyed via a MethodDescriptor object
     * which has a Class as one of its members and that member is used in
     * the MethodDescriptor.equals method. So two components that load the same
     * class via different classloaders will generate non-equal MethodDescriptor
     * objects and hence end up with different entries in the map.
     */
    private static final Map<MethodDescriptor, Reference<Method>> cache = Collections
            .synchronizedMap(new WeakHashMap<MethodDescriptor, Reference<Method>>());

    // --------------------------------------------------------- Public Methods

    
Set whether methods should be cached for greater performance or not,
default is true.
Params:
cacheMethods – true if methods should be
cached for greater performance, otherwise false
Since:
1.8.0/**
     * Set whether methods should be cached for greater performance or not,
     * default is <code>true</code>.
     *
     * @param cacheMethods <code>true</code> if methods should be
     * cached for greater performance, otherwise <code>false</code>
     * @since 1.8.0
     */
    public static synchronized void setCacheMethods(final boolean cacheMethods) {
        CACHE_METHODS = cacheMethods;
        if (!CACHE_METHODS) {
            clearCache();
        }
    }

    
Clear the method cache.
Returns:
the number of cached methods cleared
Since:
1.8.0/**
     * Clear the method cache.
     * @return the number of cached methods cleared
     * @since 1.8.0
     */
    public static synchronized int clearCache() {
        final int size = cache.size();
        cache.clear();
        return size;
    }

    
Invoke a named method whose parameter type matches the object type.
The behaviour of this method is less deterministic
than invokeExactMethod().
It loops through all methods with names that match
and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
 This is a convenient wrapper for invokeMethod(Object object, String methodName, Object[] args). 
Params:
object – invoke method on this object
methodName – get method with this name
arg – use this argument. May be null (this will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a named method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than <code>invokeExactMethod()</code>.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeMethod(Object object,String methodName,Object [] args)}.
     * </p>
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param arg use this argument. May be null (this will result in calling the
     *  parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeMethod(
            final Object object,
            final String methodName,
            final Object arg)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        final Object[] args = toArray(arg);
        return invokeMethod(object, methodName, args);
    }


    
Invoke a named method whose parameter type matches the object type.
The behaviour of this method is less deterministic than invokeExactMethod(Object object, String methodName, Object[] args). It loops through all methods with names that match and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
 This is a convenient wrapper for invokeMethod(Object object, String methodName, Object[] args, Class<?>[] parameterTypes). 
Params:
object – invoke method on this object
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a named method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     * </p>
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeMethod(
            final Object object,
            final String methodName,
            Object[] args)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeMethod(object, methodName, args, parameterTypes);
    }


    
Invoke a named method whose parameter type matches the object type.
The behaviour of this method is less deterministic than invokeExactMethod(Object object, String methodName, Object[] args, Class<?>[] parameterTypes). It loops through all methods with names that match and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
Params:
object – invoke method on this object
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
parameterTypes – match these parameters - treat null as empty array
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a named method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than {@link
     * #invokeExactMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeMethod(
            final Object object,
            final String methodName,
            Object[] args,
            Class<?>[] parameterTypes)
                throws
                    NoSuchMethodException,
                    IllegalAccessException,
                    InvocationTargetException {

        if (parameterTypes == null) {
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }
        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }

        final Method method = getMatchingAccessibleMethod(
                object.getClass(),
                methodName,
                parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: " +
                    methodName + "() on object: " + object.getClass().getName());
        }
        return method.invoke(object, args);
    }


    
Invoke a method whose parameter type matches exactly the object
type.
 This is a convenient wrapper for invokeExactMethod(Object object, String methodName, Object[] args). 
Params:
object – invoke method on this object
methodName – get method with this name
arg – use this argument. May be null (this will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a method whose parameter type matches exactly the object
     * type.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * </p>
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param arg use this argument. May be null (this will result in calling the
     *  parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeExactMethod(
            final Object object,
            final String methodName,
            final Object arg)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        final Object[] args = toArray(arg);
        return invokeExactMethod(object, methodName, args);
    }


    
Invoke a method whose parameter types match exactly the object
types.
 This uses reflection to invoke the method obtained from a call to
getAccessibleMethod().
Params:
object – invoke method on this object
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a method whose parameter types match exactly the object
     * types.</p>
     *
     * <p> This uses reflection to invoke the method obtained from a call to
     * <code>getAccessibleMethod()</code>.</p>
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeExactMethod(
            final Object object,
            final String methodName,
            Object[] args)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeExactMethod(object, methodName, args, parameterTypes);
    }


    
Invoke a method whose parameter types match exactly the parameter
types given.
This uses reflection to invoke the method obtained from a call to
getAccessibleMethod().
Params:
object – invoke method on this object
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
parameterTypes – match these parameters - treat null as empty array
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method/**
     * <p>Invoke a method whose parameter types match exactly the parameter
     * types given.</p>
     *
     * <p>This uses reflection to invoke the method obtained from a call to
     * <code>getAccessibleMethod()</code>.</p>
     *
     * @param object invoke method on this object
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     */
    public static Object invokeExactMethod(
            final Object object,
            final String methodName,
            Object[] args,
            Class<?>[] parameterTypes)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }

        if (parameterTypes == null) {
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }

        final Method method = getAccessibleMethod(
                object.getClass(),
                methodName,
                parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: " +
                    methodName + "() on object: " + object.getClass().getName());
        }
        return method.invoke(object, args);
    }

    
Invoke a static method whose parameter types match exactly the parameter
types given.
This uses reflection to invoke the method obtained from a call to getAccessibleMethod(Class<?>, String, Class<?>[]).
Params:
objectClass – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
parameterTypes – match these parameters - treat null as empty array
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a static method whose parameter types match exactly the parameter
     * types given.</p>
     *
     * <p>This uses reflection to invoke the method obtained from a call to
     * {@link #getAccessibleMethod(Class, String, Class[])}.</p>
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            Object[] args,
            Class<?>[] parameterTypes)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }

        if (parameterTypes == null) {
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }

        final Method method = getAccessibleMethod(
                objectClass,
                methodName,
                parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: " +
                    methodName + "() on class: " + objectClass.getName());
        }
        return method.invoke(null, args);
    }

    
Invoke a named static method whose parameter type matches the object type.
The behaviour of this method is less deterministic than invokeExactMethod(Object, String, Object[], Class<?>[]). It loops through all methods with names that match and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
 This is a convenient wrapper for invokeStaticMethod(Class<?> objectClass, String methodName, Object[] args). 
Params:
objectClass – invoke static method on this class
methodName – get method with this name
arg – use this argument. May be null (this will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a named static method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object, String, Object[], Class[])}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args)}.
     * </p>
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param arg use this argument. May be null (this will result in calling the
     *  parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            final Object arg)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        final Object[] args = toArray(arg);
        return invokeStaticMethod (objectClass, methodName, args);
    }


    
Invoke a named static method whose parameter type matches the object type.
The behaviour of this method is less deterministic than invokeExactMethod(Object object, String methodName, Object[] args). It loops through all methods with names that match and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
 This is a convenient wrapper for invokeStaticMethod(Class<?> objectClass, String methodName, Object[] args, Class<?>[] parameterTypes). 
Params:
objectClass – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a named static method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than {@link #invokeExactMethod(Object object,String methodName,Object [] args)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes)}.
     * </p>
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            Object[] args)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeStaticMethod (objectClass, methodName, args, parameterTypes);
    }


    
Invoke a named static method whose parameter type matches the object type.
The behaviour of this method is less deterministic than invokeExactStaticMethod(Class<?> objectClass, String methodName, Object[] args, Class<?>[] parameterTypes). It loops through all methods with names that match and then executes the first it finds with compatible parameters.
This method supports calls to methods taking primitive parameters
via passing in wrapping classes. So, for example, a Boolean class
would match a boolean primitive.
Params:
objectClass – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
parameterTypes – match these parameters - treat null as empty array
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a named static method whose parameter type matches the object type.</p>
     *
     * <p>The behaviour of this method is less deterministic
     * than {@link
     * #invokeExactStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes)}.
     * It loops through all methods with names that match
     * and then executes the first it finds with compatible parameters.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> class
     * would match a <code>boolean</code> primitive.</p>
     *
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @param parameterTypes match these parameters - treat null as empty array
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            Object[] args,
            Class<?>[] parameterTypes)
                throws
                    NoSuchMethodException,
                    IllegalAccessException,
                    InvocationTargetException {

        if (parameterTypes == null) {
            parameterTypes = EMPTY_CLASS_PARAMETERS;
        }
        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }

        final Method method = getMatchingAccessibleMethod(
                objectClass,
                methodName,
                parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: " +
                    methodName + "() on class: " + objectClass.getName());
        }
        return method.invoke(null, args);
    }


    
Invoke a static method whose parameter type matches exactly the object
type.
 This is a convenient wrapper for invokeExactStaticMethod(Class<?> objectClass, String methodName, Object[] args). 
Params:
objectClass – invoke static method on this class
methodName – get method with this name
arg – use this argument. May be null (this will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a static method whose parameter type matches exactly the object
     * type.</p>
     *
     * <p> This is a convenient wrapper for
     * {@link #invokeExactStaticMethod(Class objectClass,String methodName,Object [] args)}.
     * </p>
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param arg use this argument. May be null (this will result in calling the
     *  parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            final Object arg)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        final Object[] args = toArray(arg);
        return invokeExactStaticMethod (objectClass, methodName, args);
    }

    
Invoke a static method whose parameter types match exactly the object
types.
 This uses reflection to invoke the method obtained from a call to getAccessibleMethod(Class<?>, String, Class<?>[]).
Params:
objectClass – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
Throws:
NoSuchMethodException – if there is no such accessible method
InvocationTargetException – wraps an exception thrown by the
 method invoked
IllegalAccessException – if the requested method is not accessible
 via reflection
Returns:
The value returned by the invoked method
Since:
1.8.0/**
     * <p>Invoke a static method whose parameter types match exactly the object
     * types.</p>
     *
     * <p> This uses reflection to invoke the method obtained from a call to
     * {@link #getAccessibleMethod(Class, String, Class[])}.</p>
     *
     * @param objectClass invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array (passing null will
     *  result in calling the parameterless method with name {@code methodName}).
     * @return The value returned by the invoked method
     *
     * @throws NoSuchMethodException if there is no such accessible method
     * @throws InvocationTargetException wraps an exception thrown by the
     *  method invoked
     * @throws IllegalAccessException if the requested method is not accessible
     *  via reflection
     * @since 1.8.0
     */
    public static Object invokeExactStaticMethod(
            final Class<?> objectClass,
            final String methodName,
            Object[] args)
            throws
            NoSuchMethodException,
            IllegalAccessException,
            InvocationTargetException {

        if (args == null) {
            args = EMPTY_OBJECT_ARRAY;
        }
        final int arguments = args.length;
        final Class<?>[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeExactStaticMethod(objectClass, methodName, args, parameterTypes);
    }


    private static Object[] toArray(final Object arg) {
        Object[] args = null;
        if (arg != null) {
            args = new Object[] { arg };
        }
        return args;
    }

    
Return an accessible method (that is, one that can be invoked via
reflection) with given name and a single parameter.  If no such method
can be found, return null.
Basically, a convenience wrapper that constructs a Class
array for you.
Params:
clazz – get method from this class
methodName – get method with this name
parameterType – taking this type of parameter
Returns:
The accessible method/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) with given name and a single parameter.  If no such method
     * can be found, return <code>null</code>.
     * Basically, a convenience wrapper that constructs a <code>Class</code>
     * array for you.</p>
     *
     * @param clazz get method from this class
     * @param methodName get method with this name
     * @param parameterType taking this type of parameter
     * @return The accessible method
     */
    public static Method getAccessibleMethod(
            final Class<?> clazz,
            final String methodName,
            final Class<?> parameterType) {

        final Class<?>[] parameterTypes = {parameterType};
        return getAccessibleMethod(clazz, methodName, parameterTypes);
    }


    
Return an accessible method (that is, one that can be invoked via
reflection) with given name and parameters.  If no such method
can be found, return null. This is just a convenient wrapper for getAccessibleMethod(Method method).
Params:
clazz – get method from this class
methodName – get method with this name
parameterTypes – with these parameters types
Returns:
The accessible method/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) with given name and parameters.  If no such method
     * can be found, return <code>null</code>.
     * This is just a convenient wrapper for
     * {@link #getAccessibleMethod(Method method)}.</p>
     *
     * @param clazz get method from this class
     * @param methodName get method with this name
     * @param parameterTypes with these parameters types
     * @return The accessible method
     */
    public static Method getAccessibleMethod(
            final Class<?> clazz,
            final String methodName,
            final Class<?>[] parameterTypes) {

        try {
            final MethodDescriptor md = new MethodDescriptor(clazz, methodName, parameterTypes, true);
            // Check the cache first
            Method method = getCachedMethod(md);
            if (method != null) {
                return method;
            }

            method =  getAccessibleMethod
                    (clazz, clazz.getMethod(methodName, parameterTypes));
            cacheMethod(md, method);
            return method;
        } catch (final NoSuchMethodException e) {
            return (null);
        }
    }

    
Return an accessible method (that is, one that can be invoked via
reflection) that implements the specified Method.  If no such method
can be found, return null.
Params:
method – The method that we wish to call
Returns:
The accessible method/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified Method.  If no such method
     * can be found, return <code>null</code>.</p>
     *
     * @param method The method that we wish to call
     * @return The accessible method
     */
    public static Method getAccessibleMethod(final Method method) {

        // Make sure we have a method to check
        if (method == null) {
            return (null);
        }

        return getAccessibleMethod(method.getDeclaringClass(), method);
    }



    
Return an accessible method (that is, one that can be invoked via
reflection) that implements the specified Method.  If no such method
can be found, return null.
Params:
clazz – The class of the object
method – The method that we wish to call
Returns:
The accessible method
Since:
1.8.0/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified Method.  If no such method
     * can be found, return <code>null</code>.</p>
     *
     * @param clazz The class of the object
     * @param method The method that we wish to call
     * @return The accessible method
     * @since 1.8.0
     */
    public static Method getAccessibleMethod(Class<?> clazz, Method method) {

        // Make sure we have a method to check
        if (method == null) {
            return (null);
        }

        // If the requested method is not public we cannot call it
        if (!Modifier.isPublic(method.getModifiers())) {
            return (null);
        }

        boolean sameClass = true;
        if (clazz == null) {
            clazz = method.getDeclaringClass();
        } else {
            sameClass = clazz.equals(method.getDeclaringClass());
            if (!method.getDeclaringClass().isAssignableFrom(clazz)) {
                throw new IllegalArgumentException(clazz.getName() +
                        " is not assignable from " + method.getDeclaringClass().getName());
            }
        }

        // If the class is public, we are done
        if (Modifier.isPublic(clazz.getModifiers())) {
            if (!sameClass && !Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
                setMethodAccessible(method); // Default access superclass workaround
            }
            return (method);
        }

        final String methodName      = method.getName();
        final Class<?>[] parameterTypes = method.getParameterTypes();

        // Check the implemented interfaces and subinterfaces
        method =
                getAccessibleMethodFromInterfaceNest(clazz,
                        methodName,
                        parameterTypes);

        // Check the superclass chain
        if (method == null) {
            method = getAccessibleMethodFromSuperclass(clazz,
                        methodName,
                        parameterTypes);
        }

        return (method);
    }


    // -------------------------------------------------------- Private Methods

    
Return an accessible method (that is, one that can be invoked via
reflection) by scanning through the superclasses. If no such method
can be found, return null.
Params:
clazz – Class to be checked
methodName – Method name of the method we wish to call
parameterTypes – The parameter type signatures/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) by scanning through the superclasses. If no such method
     * can be found, return <code>null</code>.</p>
     *
     * @param clazz Class to be checked
     * @param methodName Method name of the method we wish to call
     * @param parameterTypes The parameter type signatures
     */
    private static Method getAccessibleMethodFromSuperclass
            (final Class<?> clazz, final String methodName, final Class<?>[] parameterTypes) {

        Class<?> parentClazz = clazz.getSuperclass();
        while (parentClazz != null) {
            if (Modifier.isPublic(parentClazz.getModifiers())) {
                try {
                    return parentClazz.getMethod(methodName, parameterTypes);
                } catch (final NoSuchMethodException e) {
                    return null;
                }
            }
            parentClazz = parentClazz.getSuperclass();
        }
        return null;
    }

    
Return an accessible method (that is, one that can be invoked via
reflection) that implements the specified method, by scanning through
all implemented interfaces and subinterfaces.  If no such method
can be found, return null.
 There isn't any good reason why this method must be private.
It is because there doesn't seem any reason why other classes should
call this rather than the higher level methods.
Params:
clazz – Parent class for the interfaces to be checked
methodName – Method name of the method we wish to call
parameterTypes – The parameter type signatures/**
     * <p>Return an accessible method (that is, one that can be invoked via
     * reflection) that implements the specified method, by scanning through
     * all implemented interfaces and subinterfaces.  If no such method
     * can be found, return <code>null</code>.</p>
     *
     * <p> There isn't any good reason why this method must be private.
     * It is because there doesn't seem any reason why other classes should
     * call this rather than the higher level methods.</p>
     *
     * @param clazz Parent class for the interfaces to be checked
     * @param methodName Method name of the method we wish to call
     * @param parameterTypes The parameter type signatures
     */
    private static Method getAccessibleMethodFromInterfaceNest
            (Class<?> clazz, final String methodName, final Class<?>[] parameterTypes) {

        Method method = null;

        // Search up the superclass chain
        for (; clazz != null; clazz = clazz.getSuperclass()) {

            // Check the implemented interfaces of the parent class
            final Class<?>[] interfaces = clazz.getInterfaces();
            for (int i = 0; i < interfaces.length; i++) {

                // Is this interface public?
                if (!Modifier.isPublic(interfaces[i].getModifiers())) {
                    continue;
                }

                // Does the method exist on this interface?
                try {
                    method = interfaces[i].getDeclaredMethod(methodName,
                            parameterTypes);
                } catch (final NoSuchMethodException e) {
                    /* Swallow, if no method is found after the loop then this
                     * method returns null.
                     */
                }
                if (method != null) {
                    return method;
                }

                // Recursively check our parent interfaces
                method =
                        getAccessibleMethodFromInterfaceNest(interfaces[i],
                                methodName,
                                parameterTypes);
                if (method != null) {
                    return method;
                }

            }

        }

        // We did not find anything
        return (null);
    }

    
Find an accessible method that matches the given name and has compatible parameters.
Compatible parameters mean that every method parameter is assignable from
the given parameters.
In other words, it finds a method with the given name
that will take the parameters given.

This method is slightly undeterministic since it loops
through methods names and return the first matching method.
This method is used by invokeMethod(Object object, String methodName, Object[] args, Class<?>[] parameterTypes). 
This method can match primitive parameter by passing in wrapper classes.
For example, a Boolean will match a primitive boolean
parameter.
Params:
clazz – find method in this class
methodName – find method with this name
parameterTypes – find method with compatible parameters
Returns:
The accessible method/**
     * <p>Find an accessible method that matches the given name and has compatible parameters.
     * Compatible parameters mean that every method parameter is assignable from
     * the given parameters.
     * In other words, it finds a method with the given name
     * that will take the parameters given.<p>
     *
     * <p>This method is slightly undeterministic since it loops
     * through methods names and return the first matching method.</p>
     *
     * <p>This method is used by
     * {@link
     * #invokeMethod(Object object,String methodName,Object [] args,Class[] parameterTypes)}.
     *
     * <p>This method can match primitive parameter by passing in wrapper classes.
     * For example, a <code>Boolean</code> will match a primitive <code>boolean</code>
     * parameter.
     *
     * @param clazz find method in this class
     * @param methodName find method with this name
     * @param parameterTypes find method with compatible parameters
     * @return The accessible method
     */
    public static Method getMatchingAccessibleMethod(
                                                final Class<?> clazz,
                                                final String methodName,
                                                final Class<?>[] parameterTypes) {
        // trace logging
        final Log log = LogFactory.getLog(MethodUtils.class);
        if (log.isTraceEnabled()) {
            log.trace("Matching name=" + methodName + " on " + clazz);
        }
        final MethodDescriptor md = new MethodDescriptor(clazz, methodName, parameterTypes, false);

        // see if we can find the method directly
        // most of the time this works and it's much faster
        try {
            // Check the cache first
            Method method = getCachedMethod(md);
            if (method != null) {
                return method;
            }

            method = clazz.getMethod(methodName, parameterTypes);
            if (log.isTraceEnabled()) {
                log.trace("Found straight match: " + method);
                log.trace("isPublic:" + Modifier.isPublic(method.getModifiers()));
            }

            setMethodAccessible(method); // Default access superclass workaround

            cacheMethod(md, method);
            return method;

        } catch (final NoSuchMethodException e) { /* SWALLOW */ }

        // search through all methods
        final int paramSize = parameterTypes.length;
        Method bestMatch = null;
        final Method[] methods = clazz.getMethods();
        float bestMatchCost = Float.MAX_VALUE;
        float myCost = Float.MAX_VALUE;
        for (Method method2 : methods) {
            if (method2.getName().equals(methodName)) {
                // log some trace information
                if (log.isTraceEnabled()) {
                    log.trace("Found matching name:");
                    log.trace(method2);
                }

                // compare parameters
                final Class<?>[] methodsParams = method2.getParameterTypes();
                final int methodParamSize = methodsParams.length;
                if (methodParamSize == paramSize) {
                    boolean match = true;
                    for (int n = 0 ; n < methodParamSize; n++) {
                        if (log.isTraceEnabled()) {
                            log.trace("Param=" + parameterTypes[n].getName());
                            log.trace("Method=" + methodsParams[n].getName());
                        }
                        if (!isAssignmentCompatible(methodsParams[n], parameterTypes[n])) {
                            if (log.isTraceEnabled()) {
                                log.trace(methodsParams[n] + " is not assignable from "
                                            + parameterTypes[n]);
                            }
                            match = false;
                            break;
                        }
                    }

                    if (match) {
                        // get accessible version of method
                        final Method method = getAccessibleMethod(clazz, method2);
                        if (method != null) {
                            if (log.isTraceEnabled()) {
                                log.trace(method + " accessible version of "
                                            + method2);
                            }
                            setMethodAccessible(method); // Default access superclass workaround
                            myCost = getTotalTransformationCost(parameterTypes,method.getParameterTypes());
                            if ( myCost < bestMatchCost ) {
                               bestMatch = method;
                               bestMatchCost = myCost;
                            }
                        }

                        log.trace("Couldn't find accessible method.");
                    }
                }
            }
        }
        if ( bestMatch != null ){
                 cacheMethod(md, bestMatch);
        } else {
        // didn't find a match
               log.trace("No match found.");
        }

        return bestMatch;
    }

    
Try to make the method accessible
Params:
method – The source arguments/**
     * Try to make the method accessible
     * @param method The source arguments
     */
    private static void setMethodAccessible(final Method method) {
        try {
            //
            // XXX Default access superclass workaround
            //
            // When a public class has a default access superclass
            // with public methods, these methods are accessible.
            // Calling them from compiled code works fine.
            //
            // Unfortunately, using reflection to invoke these methods
            // seems to (wrongly) to prevent access even when the method
            // modifer is public.
            //
            // The following workaround solves the problem but will only
            // work from sufficiently privilages code.
            //
            // Better workarounds would be greatfully accepted.
            //
            if (!method.isAccessible()) {
                method.setAccessible(true);
            }

        } catch (final SecurityException se) {
            // log but continue just in case the method.invoke works anyway
            final Log log = LogFactory.getLog(MethodUtils.class);
            if (!loggedAccessibleWarning) {
                boolean vulnerableJVM = false;
                try {
                    final String specVersion = System.getProperty("java.specification.version");
                    if (specVersion.charAt(0) == '1' &&
                            (specVersion.charAt(2) == '0' ||
                             specVersion.charAt(2) == '1' ||
                             specVersion.charAt(2) == '2' ||
                             specVersion.charAt(2) == '3')) {

                        vulnerableJVM = true;
                    }
                } catch (final SecurityException e) {
                    // don't know - so display warning
                    vulnerableJVM = true;
                }
                if (vulnerableJVM) {
                    log.warn(
                        "Current Security Manager restricts use of workarounds for reflection bugs "
                        + " in pre-1.4 JVMs.");
                }
                loggedAccessibleWarning = true;
            }
            log.debug("Cannot setAccessible on method. Therefore cannot use jvm access bug workaround.", se);
        }
    }

    
Returns the sum of the object transformation cost for each class in the source
argument list.
Params:
srcArgs – The source arguments
destArgs – The destination arguments
Returns:
The total transformation cost/**
     * Returns the sum of the object transformation cost for each class in the source
     * argument list.
     * @param srcArgs The source arguments
     * @param destArgs The destination arguments
     * @return The total transformation cost
     */
    private static float getTotalTransformationCost(final Class<?>[] srcArgs, final Class<?>[] destArgs) {

        float totalCost = 0.0f;
        for (int i = 0; i < srcArgs.length; i++) {
            Class<?> srcClass, destClass;
            srcClass = srcArgs[i];
            destClass = destArgs[i];
            totalCost += getObjectTransformationCost(srcClass, destClass);
        }

        return totalCost;
    }

    
Gets the number of steps required needed to turn the source class into the
destination class. This represents the number of steps in the object hierarchy
graph.
Params:
srcClass – The source class
destClass – The destination class
Returns:
The cost of transforming an object/**
     * Gets the number of steps required needed to turn the source class into the
     * destination class. This represents the number of steps in the object hierarchy
     * graph.
     * @param srcClass The source class
     * @param destClass The destination class
     * @return The cost of transforming an object
     */
    private static float getObjectTransformationCost(Class<?> srcClass, final Class<?> destClass) {
        float cost = 0.0f;
        while (srcClass != null && !destClass.equals(srcClass)) {
            if (destClass.isPrimitive()) {
                final Class<?> destClassWrapperClazz = getPrimitiveWrapper(destClass);
                if (destClassWrapperClazz != null && destClassWrapperClazz.equals(srcClass)) {
                    cost += 0.25f;
                    break;
                }
            }
            if (destClass.isInterface() && isAssignmentCompatible(destClass,srcClass)) {
                // slight penalty for interface match.
                // we still want an exact match to override an interface match, but
                // an interface match should override anything where we have to get a
                // superclass.
                cost += 0.25f;
                break;
            }
            cost++;
            srcClass = srcClass.getSuperclass();
        }

        /*
         * If the destination class is null, we've travelled all the way up to
         * an Object match. We'll penalize this by adding 1.5 to the cost.
         */
        if (srcClass == null) {
            cost += 1.5f;
        }

        return cost;
    }


    
Determine whether a type can be used as a parameter in a method invocation.
This method handles primitive conversions correctly.
In order words, it will match a Boolean to a boolean,
a Long to a long,
a Float to a float,
a Integer to a int,
and a Double to a double.
Now logic widening matches are allowed.
For example, a Long will not match a int.
Params:
parameterType – the type of parameter accepted by the method
parameterization – the type of parameter being tested
Returns:
true if the assignment is compatible./**
     * <p>Determine whether a type can be used as a parameter in a method invocation.
     * This method handles primitive conversions correctly.</p>
     *
     * <p>In order words, it will match a <code>Boolean</code> to a <code>boolean</code>,
     * a <code>Long</code> to a <code>long</code>,
     * a <code>Float</code> to a <code>float</code>,
     * a <code>Integer</code> to a <code>int</code>,
     * and a <code>Double</code> to a <code>double</code>.
     * Now logic widening matches are allowed.
     * For example, a <code>Long</code> will not match a <code>int</code>.
     *
     * @param parameterType the type of parameter accepted by the method
     * @param parameterization the type of parameter being tested
     *
     * @return true if the assignment is compatible.
     */
    public static final boolean isAssignmentCompatible(final Class<?> parameterType, final Class<?> parameterization) {
        // try plain assignment
        if (parameterType.isAssignableFrom(parameterization)) {
            return true;
        }

        if (parameterType.isPrimitive()) {
            // this method does *not* do widening - you must specify exactly
            // is this the right behaviour?
            final Class<?> parameterWrapperClazz = getPrimitiveWrapper(parameterType);
            if (parameterWrapperClazz != null) {
                return parameterWrapperClazz.equals(parameterization);
            }
        }

        return false;
    }

    
Gets the wrapper object class for the given primitive type class.
For example, passing boolean.class returns Boolean.class
Params:
primitiveType – the primitive type class for which a match is to be found
Returns:
the wrapper type associated with the given primitive
or null if no match is found/**
     * Gets the wrapper object class for the given primitive type class.
     * For example, passing <code>boolean.class</code> returns <code>Boolean.class</code>
     * @param primitiveType the primitive type class for which a match is to be found
     * @return the wrapper type associated with the given primitive
     * or null if no match is found
     */
    public static Class<?> getPrimitiveWrapper(final Class<?> primitiveType) {
        // does anyone know a better strategy than comparing names?
        if (boolean.class.equals(primitiveType)) {
            return Boolean.class;
        } else if (float.class.equals(primitiveType)) {
            return Float.class;
        } else if (long.class.equals(primitiveType)) {
            return Long.class;
        } else if (int.class.equals(primitiveType)) {
            return Integer.class;
        } else if (short.class.equals(primitiveType)) {
            return Short.class;
        } else if (byte.class.equals(primitiveType)) {
            return Byte.class;
        } else if (double.class.equals(primitiveType)) {
            return Double.class;
        } else if (char.class.equals(primitiveType)) {
            return Character.class;
        } else {

            return null;
        }
    }

    
Gets the class for the primitive type corresponding to the primitive wrapper class given.
For example, an instance of Boolean.class returns a boolean.class.
Params:
wrapperType – the
Returns:
the primitive type class corresponding to the given wrapper class,
null if no match is found/**
     * Gets the class for the primitive type corresponding to the primitive wrapper class given.
     * For example, an instance of <code>Boolean.class</code> returns a <code>boolean.class</code>.
     * @param wrapperType the
     * @return the primitive type class corresponding to the given wrapper class,
     * null if no match is found
     */
    public static Class<?> getPrimitiveType(final Class<?> wrapperType) {
        // does anyone know a better strategy than comparing names?
        if (Boolean.class.equals(wrapperType)) {
            return boolean.class;
        } else if (Float.class.equals(wrapperType)) {
            return float.class;
        } else if (Long.class.equals(wrapperType)) {
            return long.class;
        } else if (Integer.class.equals(wrapperType)) {
            return int.class;
        } else if (Short.class.equals(wrapperType)) {
            return short.class;
        } else if (Byte.class.equals(wrapperType)) {
            return byte.class;
        } else if (Double.class.equals(wrapperType)) {
            return double.class;
        } else if (Character.class.equals(wrapperType)) {
            return char.class;
        } else {
            final Log log = LogFactory.getLog(MethodUtils.class);
            if (log.isDebugEnabled()) {
                log.debug("Not a known primitive wrapper class: " + wrapperType);
            }
            return null;
        }
    }

    
Find a non primitive representation for given primitive class.
Params:
clazz – the class to find a representation for, not null
Returns:
the original class if it not a primitive. Otherwise the wrapper class. Not null/**
     * Find a non primitive representation for given primitive class.
     *
     * @param clazz the class to find a representation for, not null
     * @return the original class if it not a primitive. Otherwise the wrapper class. Not null
     */
    public static Class<?> toNonPrimitiveClass(final Class<?> clazz) {
        if (clazz.isPrimitive()) {
            final Class<?> primitiveClazz = MethodUtils.getPrimitiveWrapper(clazz);
            // the above method returns
            if (primitiveClazz != null) {
                return primitiveClazz;
            } else {
                return clazz;
            }
        } else {
            return clazz;
        }
    }


    
Return the method from the cache, if present.
Params:
md – The method descriptor
Returns:
The cached method/**
     * Return the method from the cache, if present.
     *
     * @param md The method descriptor
     * @return The cached method
     */
    private static Method getCachedMethod(final MethodDescriptor md) {
        if (CACHE_METHODS) {
            final Reference<Method> methodRef = cache.get(md);
            if (methodRef != null) {
                return methodRef.get();
            }
        }
        return null;
    }

    
Add a method to the cache.
Params:
md – The method descriptor
method – The method to cache/**
     * Add a method to the cache.
     *
     * @param md The method descriptor
     * @param method The method to cache
     */
    private static void cacheMethod(final MethodDescriptor md, final Method method) {
        if (CACHE_METHODS) {
            if (method != null) {
                cache.put(md, new WeakReference<Method>(method));
            }
        }
    }

    
Represents the key to looking up a Method by reflection.
/**
     * Represents the key to looking up a Method by reflection.
     */
    private static class MethodDescriptor {
        private final Class<?> cls;
        private final String methodName;
        private final Class<?>[] paramTypes;
        private final boolean exact;
        private final int hashCode;

        
The sole constructor.
Params:
cls –  the class to reflect, must not be null
methodName –  the method name to obtain
paramTypes – the array of classes representing the parameter types
exact – whether the match has to be exact./**
         * The sole constructor.
         *
         * @param cls  the class to reflect, must not be null
         * @param methodName  the method name to obtain
         * @param paramTypes the array of classes representing the parameter types
         * @param exact whether the match has to be exact.
         */
        public MethodDescriptor(final Class<?> cls, final String methodName, Class<?>[] paramTypes, final boolean exact) {
            if (cls == null) {
                throw new IllegalArgumentException("Class cannot be null");
            }
            if (methodName == null) {
                throw new IllegalArgumentException("Method Name cannot be null");
            }
            if (paramTypes == null) {
                paramTypes = EMPTY_CLASS_PARAMETERS;
            }

            this.cls = cls;
            this.methodName = methodName;
            this.paramTypes = paramTypes;
            this.exact= exact;

            this.hashCode = methodName.length();
        }
        
Checks for equality.
Params:
obj – object to be tested for equality
Returns:
true, if the object describes the same Method./**
         * Checks for equality.
         * @param obj object to be tested for equality
         * @return true, if the object describes the same Method.
         */
        @Override
        public boolean equals(final Object obj) {
            if (!(obj instanceof MethodDescriptor)) {
                return false;
            }
            final MethodDescriptor md = (MethodDescriptor)obj;

            return (
                exact == md.exact &&
                methodName.equals(md.methodName) &&
                cls.equals(md.cls) &&
                java.util.Arrays.equals(paramTypes, md.paramTypes)
            );
        }
        
Returns the string length of method name. I.e. if the
hashcodes are different, the objects are different. If the
hashcodes are the same, need to use the equals method to
determine equality.
Returns:
the string length of method name./**
         * Returns the string length of method name. I.e. if the
         * hashcodes are different, the objects are different. If the
         * hashcodes are the same, need to use the equals method to
         * determine equality.
         * @return the string length of method name.
         */
        @Override
        public int hashCode() {
            return hashCode;
        }
    }
}