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org.apache.commons.beanutils
Class MethodUtils  

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

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public class MethodUtils

extends java.lang.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.

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Nested Class Summary
private static class	MethodUtils.MethodDescriptor           Represents the key to looking up a Method by reflection.

 

Field Summary
private static java.util.WeakHashMap	cache           Stores a cache of Methods against MethodDescriptors, in a WeakHashMap.
private static java.lang.Class[]	emptyClassArray           An empty class array
private static java.lang.Object[]	emptyObjectArray           An empty object array
private static org.apache.commons.logging.Log	log           All logging goes through this logger
private static boolean	loggedAccessibleWarning           Only log warning about accessibility work around once

 

Constructor Summary

MethodUtils()

 

Method Summary
static java.lang.reflect.Method	getAccessibleMethod(java.lang.Class clazz, java.lang.String methodName, java.lang.Class parameterType)           Return an accessible method (that is, one that can be invoked via reflection) with given name and a single parameter.
static java.lang.reflect.Method	getAccessibleMethod(java.lang.Class clazz, java.lang.String methodName, java.lang.Class[] parameterTypes)           Return an accessible method (that is, one that can be invoked via reflection) with given name and parameters.
static java.lang.reflect.Method	getAccessibleMethod(java.lang.reflect.Method method)           Return an accessible method (that is, one that can be invoked via reflection) that implements the specified Method.
private static java.lang.reflect.Method	getAccessibleMethodFromInterfaceNest(java.lang.Class clazz, java.lang.String methodName, java.lang.Class[] parameterTypes)           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.
static java.lang.reflect.Method	getMatchingAccessibleMethod(java.lang.Class clazz, java.lang.String methodName, java.lang.Class[] parameterTypes)           Find an accessible method that matches the given name and has compatible parameters.
static java.lang.Class	getPrimitiveType(java.lang.Class wrapperType)           Gets the class for the primitive type corresponding to the primitive wrapper class given.
static java.lang.Class	getPrimitiveWrapper(java.lang.Class primitiveType)           Gets the wrapper object class for the given primitive type class.
static java.lang.Object	invokeExactMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object arg)           Invoke a method whose parameter type matches exactly the object type.
static java.lang.Object	invokeExactMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args)           Invoke a method whose parameter types match exactly the object types.
static java.lang.Object	invokeExactMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] parameterTypes)           Invoke a method whose parameter types match exactly the parameter types given.
static java.lang.Object	invokeMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object arg)           Invoke a named method whose parameter type matches the object type.
static java.lang.Object	invokeMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args)           Invoke a named method whose parameter type matches the object type.
static java.lang.Object	invokeMethod(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args, java.lang.Class[] parameterTypes)           Invoke a named method whose parameter type matches the object type.
static boolean	isAssignmentCompatible(java.lang.Class parameterType, java.lang.Class parameterization)           Determine whether a type can be used as a parameter in a method invocation.
static java.lang.Class	toNonPrimitiveClass(java.lang.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

 

Field Detail

log

private static org.apache.commons.logging.Log log

All logging goes through this logger

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loggedAccessibleWarning

private static boolean loggedAccessibleWarning

Only log warning about accessibility work around once

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emptyClassArray

private static final java.lang.Class[] emptyClassArray

An empty class array

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emptyObjectArray

private static final java.lang.Object[] emptyObjectArray

An empty object array

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cache

private static java.util.WeakHashMap cache

Stores a cache of Methods against MethodDescriptors, in a WeakHashMap.

Constructor Detail

MethodUtils

public MethodUtils()

Method Detail

invokeMethod

public static java.lang.Object invokeMethod(java.lang.Object object,
                                            java.lang.String methodName,
                                            java.lang.Object arg)
                                     throws java.lang.NoSuchMethodException,
                                            java.lang.IllegalAccessException,
                                            java.lang.reflect.InvocationTargetException

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

The behaviour of this method is less deterministic than invokeExactMethod(java.lang.Object, java.lang.String, java.lang.Object) 55 . 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) 55 .

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invokeMethod

public static java.lang.Object invokeMethod(java.lang.Object object,
                                            java.lang.String methodName,
                                            java.lang.Object[] args)
                                     throws java.lang.NoSuchMethodException,
                                            java.lang.IllegalAccessException,
                                            java.lang.reflect.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) 55 . 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) 55 .

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invokeMethod

public static java.lang.Object invokeMethod(java.lang.Object object,
                                            java.lang.String methodName,
                                            java.lang.Object[] args,
                                            java.lang.Class[] parameterTypes)
                                     throws java.lang.NoSuchMethodException,
                                            java.lang.IllegalAccessException,
                                            java.lang.reflect.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) 55 . 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.

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invokeExactMethod

public static java.lang.Object invokeExactMethod(java.lang.Object object,
                                                 java.lang.String methodName,
                                                 java.lang.Object arg)
                                          throws java.lang.NoSuchMethodException,
                                                 java.lang.IllegalAccessException,
                                                 java.lang.reflect.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) 55 .

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invokeExactMethod

public static java.lang.Object invokeExactMethod(java.lang.Object object,
                                                 java.lang.String methodName,
                                                 java.lang.Object[] args)
                                          throws java.lang.NoSuchMethodException,
                                                 java.lang.IllegalAccessException,
                                                 java.lang.reflect.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(java.lang.Class, java.lang.String, java.lang.Class) 55 .

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invokeExactMethod

public static java.lang.Object invokeExactMethod(java.lang.Object object,
                                                 java.lang.String methodName,
                                                 java.lang.Object[] args,
                                                 java.lang.Class[] parameterTypes)
                                          throws java.lang.NoSuchMethodException,
                                                 java.lang.IllegalAccessException,
                                                 java.lang.reflect.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(java.lang.Class, java.lang.String, java.lang.Class) 55 .

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getAccessibleMethod

public static java.lang.reflect.Method getAccessibleMethod(java.lang.Class clazz,
                                                           java.lang.String methodName,
                                                           java.lang.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.

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getAccessibleMethod

public static java.lang.reflect.Method getAccessibleMethod(java.lang.Class clazz,
                                                           java.lang.String methodName,
                                                           java.lang.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) 55 .

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getAccessibleMethod

public static java.lang.reflect.Method getAccessibleMethod(java.lang.reflect.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.

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getAccessibleMethodFromInterfaceNest

private static java.lang.reflect.Method getAccessibleMethodFromInterfaceNest(java.lang.Class clazz,
                                                                             java.lang.String methodName,
                                                                             java.lang.Class[] parameterTypes)

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.

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getMatchingAccessibleMethod

public static java.lang.reflect.Method getMatchingAccessibleMethod(java.lang.Class clazz,
                                                                   java.lang.String methodName,
                                                                   java.lang.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) 55 .

This method can match primitive parameter by passing in wrapper classes. For example, a Boolean will match a primitive boolean parameter.

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isAssignmentCompatible

public static final boolean isAssignmentCompatible(java.lang.Class parameterType,
                                                   java.lang.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.

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getPrimitiveWrapper

public static java.lang.Class getPrimitiveWrapper(java.lang.Class primitiveType)

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

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getPrimitiveType

public static java.lang.Class getPrimitiveType(java.lang.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.

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toNonPrimitiveClass

public static java.lang.Class toNonPrimitiveClass(java.lang.Class clazz)

Find a non primitive representation for given primitive class.

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> commons >> [ beanutils overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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