Package org.esa.snap.core.util

Class PrivilegedAccessor

java.lang.Object

org.esa.snap.core.util.PrivilegedAccessor

public class PrivilegedAccessor
extends Object

a.k.a. The "ObjectMolester"

This class is used to access a method or field of an object no matter what the access modifier of the method or field. The syntax for accessing fields and methods is out of the ordinary because this class uses reflection to peel away protection.

Here is an example of using this to access a private member. resolveName is a private method of Class.

 Class c = Class.class;
 System.out.println(PrivilegedAccessor.invokeMethod(c, "resolveName","/ise/library/PrivilegedAccessor"));
 

Constructor Summary

Constructors

Constructor	Description
PrivilegedAccessor()

Method Summary

Modifier and Type	Method	Description
static Field	getField(Class thisClass, String fieldName)	Return the named field from the given class.
static Method	getMethod(Class thisClass, String methodName, Class[] classTypes)	Return the named method with a method signature matching classTypes from the given class.
static Method	getMethod(Object instance, String methodName, Class[] classTypes)	Gets the named method with a method signature matching classTypes from the given insance and returns it as an object.
static Object	getNewInstance(String classname, Object[] args)	Creates a new instance of the named class initialized with the given arguments.
static Object	getStaticValue(Class c, String fieldName)	Gets the value of the named static field and returns it as an object.
static Object	getValue(Object instance, String fieldName)	Gets the value of the named field and returns it as an object.
static Object	invokeMethod(Object instance, String methodName, Object arg)	Calls a method on the given object instance with the given argument.
static Object	invokeMethod(Object instance, String methodName, Object[] args)	Calls a method on the given object instance with the given arguments.
static void	setStaticValue(Class c, String fieldName, Object value)	Sets the value of the named static field.
static void	setValue(Object instance, String fieldName, Object value)

Methods inherited from class java.lang.Object

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

Constructor Detail

PrivilegedAccessor

public PrivilegedAccessor()

Method Detail

getValue

public static Object getValue(Object instance,
                              String fieldName)
                       throws IllegalAccessException,
                              NoSuchFieldException

Gets the value of the named field and returns it as an object.

Parameters:

instance - the object instance

fieldName - the name of the field

Returns:

an object representing the value of the field

Throws:

IllegalAccessException

NoSuchFieldException

setValue

public static void setValue(Object instance,
                            String fieldName,
                            Object value)
                     throws IllegalAccessException,
                            NoSuchFieldException

Throws:

IllegalAccessException

NoSuchFieldException

getStaticValue

public static Object getStaticValue(Class c,
                                    String fieldName)
                             throws IllegalAccessException,
                                    NoSuchFieldException

Gets the value of the named static field and returns it as an object.

Parameters:

c - the class containing the static field

fieldName - the name of the field

Returns:

an object representing the value of the field

Throws:

IllegalAccessException

NoSuchFieldException

setStaticValue

public static void setStaticValue(Class c,
                                  String fieldName,
                                  Object value)
                           throws IllegalAccessException,
                                  NoSuchFieldException

Sets the value of the named static field.

Parameters:

c - the class containing the static field

fieldName - the name of the field

Throws:

IllegalAccessException

NoSuchFieldException

invokeMethod

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

Calls a method on the given object instance with the given argument.

Parameters:

instance - the object instance

methodName - the name of the method to invoke

arg - the argument to pass to the method

Throws:

NoSuchMethodException

IllegalAccessException

InvocationTargetException

See Also:

invokeMethod(Object, String, Object[])

invokeMethod

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

Calls a method on the given object instance with the given arguments.

Parameters:

instance - the object instance

methodName - the name of the method to invoke

args - an array of objects to pass as arguments

Throws:

NoSuchMethodException

IllegalAccessException

InvocationTargetException

See Also:

invokeMethod(Object, String, Object)

getMethod

public static Method getMethod(Object instance,
                               String methodName,
                               Class[] classTypes)
                        throws NoSuchMethodException

Gets the named method with a method signature matching classTypes from the given insance and returns it as an object.

Parameters:

instance - the object instance

methodName - the method name

classTypes - the method argument types

Throws:

NoSuchMethodException

getField

public static Field getField(Class thisClass,
                             String fieldName)
                      throws NoSuchFieldException

Return the named field from the given class.

Parameters:

thisClass - The class

fieldName - The field name

Throws:

NoSuchFieldException

getMethod

public static Method getMethod(Class thisClass,
                               String methodName,
                               Class[] classTypes)
                        throws NoSuchMethodException

Return the named method with a method signature matching classTypes from the given class.

Parameters:

thisClass - the class containing the method

methodName - the name of the method

classTypes - the method argument types

Throws:

NoSuchMethodException

getNewInstance

public static Object getNewInstance(String classname,
                                    Object[] args)
                             throws ClassNotFoundException,
                                    InstantiationException,
                                    NoSuchMethodException,
                                    IllegalAccessException,
                                    InvocationTargetException

Creates a new instance of the named class initialized with the given arguments.

Parameters:

classname - the name of the class to instantiate.

args - the arguments to pass as parameters to the constructor of the class.

Returns:

the instantiated object

Throws:

ClassNotFoundException

InstantiationException

NoSuchMethodException

IllegalAccessException

InvocationTargetException