/*
 * 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.lang.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.ClassUtils;

 Utility reflection methods focused on methods, originally from Commons BeanUtils.
Differences from the BeanUtils version may be noted, especially where similar functionality
already existed within Lang.

Known Limitations
Accessing Public Methods In A Default Access Superclass
There is an issue when invoking public methods contained in a default access superclass on JREs prior to 1.4.
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 privileges. 
If this call fails then the method may fail.
Author:
Apache Software Foundation, Craig R. McClanahan, Ralph Schaer, Chris Audley, Rey François, Gregor Raýman, Jan Sorensen, Robert Burrell Donkin, Matt Benson
Since:
2.5
Version:
$Id: MethodUtils.java 911986 2010-02-19 21:19:05Z niallp $/**
 * <p> Utility reflection methods focused on methods, originally from Commons BeanUtils.
 * Differences from the BeanUtils version may be noted, especially where similar functionality
 * already existed within Lang.
 * </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 on JREs prior to 1.4.
 * 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 privileges. 
 * If this call fails then the method may fail.</p>
 *
 * @author Apache Software Foundation
 * @author Craig R. McClanahan
 * @author Ralph Schaer
 * @author Chris Audley
 * @author Rey Fran&#231;ois
 * @author Gregor Ra&#253;man
 * @author Jan Sorensen
 * @author Robert Burrell Donkin
 * @author Matt Benson
 * @since 2.5
 * @version $Id: MethodUtils.java 911986 2010-02-19 21:19:05Z niallp $
 */
public class MethodUtils {

    
MethodUtils instances should NOT be constructed in standard programming.
Instead, the class should be used as
MethodUtils.getAccessibleMethod(method).
This constructor is public to permit tools that require a JavaBean
instance to operate.
/**
     * <p>MethodUtils instances should NOT be constructed in standard programming.
     * Instead, the class should be used as
     * <code>MethodUtils.getAccessibleMethod(method)</code>.</p>
     *
     * <p>This constructor is public to permit tools that require a JavaBean
     * instance to operate.</p>
     */
    public MethodUtils() {
        super();
    }

    
Invoke a named method whose parameter type matches the object type.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
This method supports calls to methods taking primitive parameters 
via passing in wrapping classes. So, for example, a Boolean object
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
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>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters 
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> object
     * 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
     * @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(Object object, String methodName,
            Object arg) throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        return invokeMethod(object, methodName, new Object[] { arg });
    }

    
Invoke a named method whose parameter type matches the object type.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
This method supports calls to methods taking primitive parameters 
via passing in wrapping classes. So, for example, a Boolean object
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
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>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters 
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> object
     * 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
     * @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(Object object, String methodName,
            Object[] args) throws NoSuchMethodException,
            IllegalAccessException, InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        int arguments = args.length;
        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.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
This method supports calls to methods taking primitive parameters 
via passing in wrapping classes. So, for example, a Boolean object
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
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>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</p>
     *
     * <p>This method supports calls to methods taking primitive parameters 
     * via passing in wrapping classes. So, for example, a <code>Boolean</code> object
     * 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
     * @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(Object object, String methodName,
            Object[] args, Class[] parameterTypes)
            throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        if (parameterTypes == null) {
            parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
        }
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        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
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
     * @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(Object object, String methodName,
            Object arg) throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        return invokeExactMethod(object, methodName, new Object[] { arg });
    }

    
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
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
     * @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(Object object, String methodName,
            Object[] args) throws NoSuchMethodException,
            IllegalAccessException, InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        int arguments = args.length;
        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
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
     * @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(Object object, String methodName,
            Object[] args, Class[] parameterTypes)
            throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        if (parameterTypes == null) {
            parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
        }
        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:
cls – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array
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 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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array
     * @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 invokeExactStaticMethod(Class cls, String methodName,
            Object[] args, Class[] parameterTypes)
            throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        if (parameterTypes == null) {
            parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
        }
        Method method = getAccessibleMethod(cls, methodName, parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: "
                    + methodName + "() on class: " + cls.getName());
        }
        return method.invoke(null, args);
    }

    
Invoke a named static method whose parameter type matches the object type.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
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:
cls – invoke static method on this class
methodName – get method with this name
arg – use this argument
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 static method whose parameter type matches the object type.</p>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param arg use this argument
     * @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 invokeStaticMethod(Class cls, String methodName,
            Object arg) throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        return invokeStaticMethod(cls, methodName, new Object[] { arg });
    }

    
Invoke a named static method whose parameter type matches the object type.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
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:
cls – invoke static method on this class
methodName – get method with this name
args – use these arguments - 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 static method whose parameter type matches the object type.</p>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - 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 invokeStaticMethod(Class cls, String methodName,
            Object[] args) throws NoSuchMethodException,
            IllegalAccessException, InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        int arguments = args.length;
        Class[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeStaticMethod(cls, methodName, args, parameterTypes);
    }

    
Invoke a named static method whose parameter type matches the object type.
This method delegates the method search to getMatchingAccessibleMethod(Class, String, Class[]).
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:
cls – invoke static method on this class
methodName – get method with this name
args – use these arguments - treat null as empty array
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 static method whose parameter type matches the object type.</p>
     *
     * <p>This method delegates the method search to {@link #getMatchingAccessibleMethod(Class, String, Class[])}.</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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - treat null as empty array
     * @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 invokeStaticMethod(Class cls, String methodName,
            Object[] args, Class[] parameterTypes)
            throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        if (parameterTypes == null) {
            parameterTypes = ArrayUtils.EMPTY_CLASS_ARRAY;
        }
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        Method method = getMatchingAccessibleMethod(cls, methodName,
                parameterTypes);
        if (method == null) {
            throw new NoSuchMethodException("No such accessible method: "
                    + methodName + "() on class: " + cls.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:
cls – invoke static method on this class
methodName – get method with this name
arg – use this argument
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 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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param arg use this argument
     * @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 invokeExactStaticMethod(Class cls, String methodName,
            Object arg) throws NoSuchMethodException, IllegalAccessException,
            InvocationTargetException {
        return invokeExactStaticMethod(cls, methodName, new Object[] { arg });
    }

    
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:
cls – invoke static method on this class
methodName – get method with this name
args – use these arguments - 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 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 cls invoke static method on this class
     * @param methodName get method with this name
     * @param args use these arguments - 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 invokeExactStaticMethod(Class cls, String methodName,
            Object[] args) throws NoSuchMethodException,
            IllegalAccessException, InvocationTargetException {
        if (args == null) {
            args = ArrayUtils.EMPTY_OBJECT_ARRAY;
        }
        int arguments = args.length;
        Class[] parameterTypes = new Class[arguments];
        for (int i = 0; i < arguments; i++) {
            parameterTypes[i] = args[i].getClass();
        }
        return invokeExactStaticMethod(cls, methodName, args, parameterTypes);
    }

    
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:
cls – 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 cls 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(Class cls, String methodName,
            Class parameterType) {
        return getAccessibleMethod(cls, methodName,
                new Class[] { parameterType });
    }

    
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:
cls – 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 cls 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(Class cls, String methodName,
            Class[] parameterTypes) {
        try {
            return getAccessibleMethod(cls.getMethod(methodName,
                    parameterTypes));
        } catch (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(Method method) {
        if (!MemberUtils.isAccessible(method)) {
            return null;
        }
        // If the declaring class is public, we are done
        Class cls = method.getDeclaringClass();
        if (Modifier.isPublic(cls.getModifiers())) {
            return method;
        }
        String methodName = method.getName();
        Class[] parameterTypes = method.getParameterTypes();

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

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

    
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:
cls – Class to be checked
methodName – Method name of the method we wish to call
parameterTypes – The parameter type signatures
Returns:
the accessible method or null if not found/**
     * <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 cls Class to be checked
     * @param methodName Method name of the method we wish to call
     * @param parameterTypes The parameter type signatures
     * @return the accessible method or <code>null</code> if not found
     */
    private static Method getAccessibleMethodFromSuperclass(Class cls,
            String methodName, Class[] parameterTypes) {
        Class parentClass = cls.getSuperclass();
        while (parentClass != null) {
            if (Modifier.isPublic(parentClass.getModifiers())) {
                try {
                    return parentClass.getMethod(methodName, parameterTypes);
                } catch (NoSuchMethodException e) {
                    return null;
                }
            }
            parentClass = parentClass.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:
cls – Parent class for the interfaces to be checked
methodName – Method name of the method we wish to call
parameterTypes – The parameter type signatures
Returns:
the accessible method or null if not found/**
     * <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 cls 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
     * @return the accessible method or <code>null</code> if not found
     */
    private static Method getAccessibleMethodFromInterfaceNest(Class cls,
            String methodName, Class[] parameterTypes) {
        Method method = null;

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

            // Check the implemented interfaces of the parent class
            Class[] interfaces = cls.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 (NoSuchMethodException e) {
                    /*
                     * Swallow, if no method is found after the loop then this
                     * method returns null.
                     */
                }
                if (method != null) {
                    break;
                }
                // Recursively check our parent interfaces
                method = getAccessibleMethodFromInterfaceNest(interfaces[i],
                        methodName, parameterTypes);
                if (method != null) {
                    break;
                }
            }
        }
        return method;
    }

    
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 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:
cls – find method in this class
methodName – find method with this name
parameterTypes – find method with most 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 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 cls find method in this class
     * @param methodName find method with this name
     * @param parameterTypes find method with most compatible parameters 
     * @return The accessible method
     */
    public static Method getMatchingAccessibleMethod(Class cls,
            String methodName, Class[] parameterTypes) {
        try {
            Method method = cls.getMethod(methodName, parameterTypes);
            MemberUtils.setAccessibleWorkaround(method);
            return method;
        } catch (NoSuchMethodException e) { /* SWALLOW */
        }
        // search through all methods
        Method bestMatch = null;
        Method[] methods = cls.getMethods();
        for (int i = 0, size = methods.length; i < size; i++) {
            if (methods[i].getName().equals(methodName)) {
                // compare parameters
                if (ClassUtils.isAssignable(parameterTypes, methods[i]
                        .getParameterTypes(), true)) {
                    // get accessible version of method
                    Method accessibleMethod = getAccessibleMethod(methods[i]);
                    if (accessibleMethod != null) {
                        if (bestMatch == null
                                || MemberUtils.compareParameterTypes(
                                        accessibleMethod.getParameterTypes(),
                                        bestMatch.getParameterTypes(),
                                        parameterTypes) < 0) {
                            bestMatch = accessibleMethod;
                        }
                    }
                }
            }
        }
        if (bestMatch != null) {
            MemberUtils.setAccessibleWorkaround(bestMatch);
        }
        return bestMatch;
    }
}