org.apache.commons.beanutils
Class MethodUtils

java.lang.Object
  org.apache.commons.beanutils.MethodUtils

public class MethodUtils
extends Object

Utility reflection methods focussed 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.

Author:

Craig R. McClanahan, Ralph Schaer, Chris Audley, Rey François, Gregor Raýman, Jan Sorensen, Robert Burrell Donkin

Constructor Summary

MethodUtils()

Method Summary

static int	clearCache() Clear the method cache.
static Method	getAccessibleMethod(Class clazz, Method method) Return an accessible method (that is, one that can be invoked via reflection) that implements the specified Method.
static Method	getAccessibleMethod(Class clazz, String methodName, Class parameterType) Return an accessible method (that is, one that can be invoked via reflection) with given name and a single parameter.
static Method	getAccessibleMethod(Class clazz, String methodName, Class[] parameterTypes) Return an accessible method (that is, one that can be invoked via reflection) with given name and parameters.
static Method	getAccessibleMethod(Method method) Return an accessible method (that is, one that can be invoked via reflection) that implements the specified Method.
static Method	getMatchingAccessibleMethod(Class clazz, String methodName, Class[] parameterTypes) Find an accessible method that matches the given name and has compatible parameters.
static Class	getPrimitiveType(Class wrapperType) Gets the class for the primitive type corresponding to the primitive wrapper class given.
static Class	getPrimitiveWrapper(Class primitiveType) Gets the wrapper object class for the given primitive type class.
static Object	invokeExactMethod(Object object, String methodName, Object arg) Invoke a method whose parameter type matches exactly the object type.
static Object	invokeExactMethod(Object object, String methodName, Object[] args) Invoke a method whose parameter types match exactly the object types.
static Object	invokeExactMethod(Object object, String methodName, Object[] args, Class[] parameterTypes) Invoke a method whose parameter types match exactly the parameter types given.
static Object	invokeExactStaticMethod(Class objectClass, String methodName, Object arg) Invoke a static method whose parameter type matches exactly the object type.
static Object	invokeExactStaticMethod(Class objectClass, String methodName, Object[] args) Invoke a static method whose parameter types match exactly the object types.
static Object	invokeExactStaticMethod(Class objectClass, String methodName, Object[] args, Class[] parameterTypes) Invoke a static method whose parameter types match exactly the parameter types given.
static Object	invokeMethod(Object object, String methodName, Object arg) Invoke a named method whose parameter type matches the object type.
static Object	invokeMethod(Object object, String methodName, Object[] args) Invoke a named method whose parameter type matches the object type.
static Object	invokeMethod(Object object, String methodName, Object[] args, Class[] parameterTypes) Invoke a named method whose parameter type matches the object type.
static Object	invokeStaticMethod(Class objectClass, String methodName, Object arg) Invoke a named static method whose parameter type matches the object type.
static Object	invokeStaticMethod(Class objectClass, String methodName, Object[] args) Invoke a named static method whose parameter type matches the object type.
static Object	invokeStaticMethod(Class objectClass, String methodName, Object[] args, Class[] parameterTypes) Invoke a named static method whose parameter type matches the object type.
static boolean	isAssignmentCompatible(Class parameterType, Class parameterization) Determine whether a type can be used as a parameter in a method invocation.
static void	setCacheMethods(boolean cacheMethods) Set whether methods should be cached for greater performance or not, default is true.
static Class	toNonPrimitiveClass(Class clazz) Find a non primitive representation for given primitive class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MethodUtils

public MethodUtils()

Method Detail

setCacheMethods

public static void setCacheMethods(boolean cacheMethods)

Set whether methods should be cached for greater performance or not, default is true.

Parameters:

cacheMethods - true if methods should be cached for greater performance, otherwise false

Since:

1.8.0

clearCache

public static int clearCache()

Clear the method cache.

Returns:

the number of cached methods cleared

Since:

1.8.0

invokeMethod

public static Object invokeMethod(Object object,
                                  String methodName,
                                  Object arg)
                           throws NoSuchMethodException,
                                  IllegalAccessException,
                                  InvocationTargetException

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 compatable 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).

Parameters:

object - invoke method on this object

methodName - get method with this name

arg - use this argument

Returns:

The value returned by the invoked method

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

invokeMethod

public static Object invokeMethod(Object object,
                                  String methodName,
                                  Object[] args)
                           throws NoSuchMethodException,
                                  IllegalAccessException,
                                  InvocationTargetException

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 compatable 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).

Parameters:

object - invoke method on this object

methodName - get method with this name

args - use these arguments - treat null as empty array

Returns:

The value returned by the invoked method

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

invokeMethod

public static Object invokeMethod(Object object,
                                  String methodName,
                                  Object[] args,
                                  Class[] parameterTypes)
                           throws NoSuchMethodException,
                                  IllegalAccessException,
                                  InvocationTargetException

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 compatable 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.

Parameters:

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

Returns:

The value returned by the invoked method

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

invokeExactMethod

public static Object invokeExactMethod(Object object,
                                       String methodName,
                                       Object arg)
                                throws NoSuchMethodException,
                                       IllegalAccessException,
                                       InvocationTargetException

Invoke a method whose parameter type matches exactly the object type.

This is a convenient wrapper for invokeExactMethod(Object object,String methodName,Object [] args).

Parameters:

object - invoke method on this object

methodName - get method with this name

arg - use this argument

Returns:

The value returned by the invoked method

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

invokeExactMethod

public static Object invokeExactMethod(Object object,
                                       String methodName,
                                       Object[] args)
                                throws NoSuchMethodException,
                                       IllegalAccessException,
                                       InvocationTargetException

Invoke a method whose parameter types match exactly the object types.

This uses reflection to invoke the method obtained from a call to getAccessibleMethod().

Parameters:

object - invoke method on this object

methodName - get method with this name

args - use these arguments - treat null as empty array

Returns:

The value returned by the invoked method

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

invokeExactMethod

public static Object invokeExactMethod(Object object,
                                       String methodName,
                                       Object[] args,
                                       Class[] parameterTypes)
                                throws NoSuchMethodException,
                                       IllegalAccessException,
                                       InvocationTargetException

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().

Parameters:

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

Returns:

The value returned by the invoked method

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

invokeExactStaticMethod

public static Object invokeExactStaticMethod(Class objectClass,
                                             String methodName,
                                             Object[] args,
                                             Class[] parameterTypes)
                                      throws NoSuchMethodException,
                                             IllegalAccessException,
                                             InvocationTargetException

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[]).

Parameters:

objectClass - 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

Returns:

The value returned by the invoked method

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

Since:

1.8.0

invokeStaticMethod

public static Object invokeStaticMethod(Class objectClass,
                                        String methodName,
                                        Object arg)
                                 throws NoSuchMethodException,
                                        IllegalAccessException,
                                        InvocationTargetException

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 compatable 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).

Parameters:

objectClass - invoke static method on this class

methodName - get method with this name

arg - use this argument

Returns:

The value returned by the invoked method

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

Since:

1.8.0

invokeStaticMethod

public static Object invokeStaticMethod(Class objectClass,
                                        String methodName,
                                        Object[] args)
                                 throws NoSuchMethodException,
                                        IllegalAccessException,
                                        InvocationTargetException

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 compatable 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).

Parameters:

objectClass - invoke static method on this class

methodName - get method with this name

args - use these arguments - treat null as empty array

Returns:

The value returned by the invoked method

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

Since:

1.8.0

invokeStaticMethod

public static Object invokeStaticMethod(Class objectClass,
                                        String methodName,
                                        Object[] args,
                                        Class[] parameterTypes)
                                 throws NoSuchMethodException,
                                        IllegalAccessException,
                                        InvocationTargetException

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 compatable 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.

Parameters:

objectClass - 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

Returns:

The value returned by the invoked method

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

Since:

1.8.0

invokeExactStaticMethod

public static Object invokeExactStaticMethod(Class objectClass,
                                             String methodName,
                                             Object arg)
                                      throws NoSuchMethodException,
                                             IllegalAccessException,
                                             InvocationTargetException

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).

Parameters:

objectClass - invoke static method on this class

methodName - get method with this name

arg - use this argument

Returns:

The value returned by the invoked method

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

Since:

1.8.0

invokeExactStaticMethod

public static Object invokeExactStaticMethod(Class objectClass,
                                             String methodName,
                                             Object[] args)
                                      throws NoSuchMethodException,
                                             IllegalAccessException,
                                             InvocationTargetException

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[]).

Parameters:

objectClass - invoke static method on this class

methodName - get method with this name

args - use these arguments - treat null as empty array

Returns:

The value returned by the invoked method

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

Since:

1.8.0

getAccessibleMethod

public static Method getAccessibleMethod(Class clazz,
                                         String methodName,
                                         Class parameterType)

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.

Parameters:

clazz - get method from this class

methodName - get method with this name

parameterType - taking this type of parameter

Returns:

The accessible method

getAccessibleMethod

public static Method getAccessibleMethod(Class clazz,
                                         String methodName,
                                         Class[] 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).

Parameters:

clazz - get method from this class

methodName - get method with this name

parameterTypes - with these parameters types

Returns:

The accessible method

getAccessibleMethod

public static Method getAccessibleMethod(Method 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.

Parameters:

method - The method that we wish to call

Returns:

The accessible method

getAccessibleMethod

public static Method getAccessibleMethod(Class clazz,
                                         Method 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.

Parameters:

clazz - The class of the object

method - The method that we wish to call

Returns:

The accessible method

Since:

1.8.0

getMatchingAccessibleMethod

public static Method getMatchingAccessibleMethod(Class clazz,
                                                 String methodName,
                                                 Class[] parameterTypes)

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 undeterminstic 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.

Parameters:

clazz - find method in this class

methodName - find method with this name

parameterTypes - find method with compatible parameters

Returns:

The accessible method

isAssignmentCompatible

public static final boolean isAssignmentCompatible(Class parameterType,
                                                   Class parameterization)

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.

Parameters:

parameterType - the type of parameter accepted by the method

parameterization - the type of parameter being tested

Returns:

true if the assignement is compatible.

getPrimitiveWrapper

public static Class getPrimitiveWrapper(Class primitiveType)

Gets the wrapper object class for the given primitive type class. For example, passing boolean.class returns Boolean.class

Parameters:

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

getPrimitiveType

public static Class getPrimitiveType(Class wrapperType)

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.

Parameters:

wrapperType - the

Returns:

the primitive type class corresponding to the given wrapper class, null if no match is found

toNonPrimitiveClass

public static Class toNonPrimitiveClass(Class clazz)

Find a non primitive representation for given primitive class.

Parameters:

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