public class

MethodUtils

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

Class Overview

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.

Summary

Public Constructors
MethodUtils()
Public Methods
synchronized static int clearCache()
Clear the method cache.
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(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(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[] args)

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

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, Class[] parameterTypes)

Invoke a static method whose parameter types match exactly the parameter types given.

static Object invokeMethod(Object object, String methodName, Object[] args, Class[] parameterTypes)

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 arg)

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.

final static boolean isAssignmentCompatible(Class parameterType, Class parameterization)

Determine whether a type can be used as a parameter in a method invocation.

synchronized 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.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public MethodUtils ()

Public Methods

public static synchronized int clearCache ()

Clear the method cache.

Returns
  • the number of cached methods cleared

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).

Parameters
clazz get method from this class
methodName get method with this name
parameterTypes with these parameters types
Returns
  • The accessible method

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

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

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

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, String, Object[], Class[]).

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

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

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

public static Object invokeExactMethod (Object object, String methodName, Object arg)

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

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

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

public static Object invokeExactMethod (Object object, String methodName, Object[] 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().

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

public static Object invokeExactMethod (Object object, String methodName, Object[] args, Class[] 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().

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

public static Object invokeExactStaticMethod (Class objectClass, String methodName, Object[] 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[]).

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

public static Object invokeExactStaticMethod (Class objectClass, String methodName, Object arg)

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

This is a convenient wrapper for invokeExactStaticMethod(Class, String, Object[]).

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

public static Object invokeExactStaticMethod (Class objectClass, String methodName, Object[] args, Class[] parameterTypes)

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

public static Object invokeMethod (Object object, String methodName, Object[] args, Class[] parameterTypes)

Invoke a named 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.

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

public static Object invokeMethod (Object object, String methodName, Object[] args)

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

The behaviour of this method is less deterministic than invokeExactMethod(Object, String, Object[]). 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, String, Object[], Class[]).

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

public static Object invokeMethod (Object object, String methodName, Object arg)

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, String, Object[]).

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

public static Object invokeStaticMethod (Class objectClass, String methodName, Object arg)

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, String, Object[]).

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

public static Object invokeStaticMethod (Class objectClass, String methodName, Object[] 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[]). 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, String, Object[], 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

public static Object invokeStaticMethod (Class objectClass, String methodName, Object[] args, Class[] parameterTypes)

Invoke a named static method whose parameter type matches the object type.

The behaviour of this method is less deterministic than invokeExactStaticMethod(Class, 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.

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

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.

public static synchronized 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

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