com.lf.vfslib.lang

Class ReflectionUtils

java.lang.Object

com.lf.vfslib.lang.ReflectionUtils

public class ReflectionUtils
extends Object

This class holds various methods for common use with reflection.

Since:

1.6

Author:

Axel Schwolow

Constructor Summary

Constructors

Constructor and Description
ReflectionUtils() Constructor method for i18n purposes only.

Method Summary

Modifier and Type	Method and Description
static Object	getDeclaredField(Object target, Class clazz, String name) Extracts the value of the instance variable via reflection (also protected, private etc.).
static Object	getDeclaredField(Object target, String name) Extracts the value of the instance variable via reflection (also protected, private etc.).
static Object	getStaticField(String classname, String fieldname) Extracts the value of the static field via reflection (only public).
static Object	invoke(Object target, String methodname, String[] paramtypes, Object... args) Invokes a method using reflection.
static Object	invokeStatic(String classname, String methodname, String[] paramtypes, Object... args) Invokes a static (class) method using reflection.
static Object	newInstance(String classname, String[] paramtypes, Object... initargs) Creates a new instance of the given class using reflection (also used for the paramtypes classes).

Methods inherited from class java.lang.Object

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

Constructor Detail

ReflectionUtils

public ReflectionUtils()
                throws InstantiationException

Constructor method for i18n purposes only.

Throws:

InstantiationException - Error indication

Method Detail

getDeclaredField

public static Object getDeclaredField(Object target,
                                      Class clazz,
                                      String name)
                               throws NoSuchFieldException,
                                      IllegalAccessException

Extracts the value of the instance variable via reflection (also protected, private etc.).

The clazz parameter may be one of the subclasses of target.

Parameters:

target - The object to be accessed

name - The name of the variable to access

clazz - The (sub)class of interest, target class if null

Returns:

Instance variable value, may be null

Throws:

NullPointerException - If the parameters are null

NoSuchFieldException - Error indication

IllegalAccessException - Error indication

getDeclaredField

public static Object getDeclaredField(Object target,
                                      String name)
                               throws NoSuchFieldException,
                                      IllegalAccessException

Extracts the value of the instance variable via reflection (also protected, private etc.).

Parameters:

target - The object to be accessed

name - The name of the variable to access

Returns:

Instance variable value, may be null

Throws:

NullPointerException - If the parameters are null

NoSuchFieldException - Error indication

IllegalAccessException - Error indication

newInstance

public static Object newInstance(String classname,
                                 String[] paramtypes,
                                 Object... initargs)

Creates a new instance of the given class using reflection (also used for the paramtypes classes).

Parameters:

classname - The object to be accessed

paramtypes - The parameter types for constructor, null = default constructor

initargs - The arguments for constructor, null = default constructor

Returns:

Instance reference, null if an error occurred

invoke

public static Object invoke(Object target,
                            String methodname,
                            String[] paramtypes,
                            Object... args)

Invokes a method using reflection.

Parameters:

target - The object to be accessed

methodname - The method to be invoked

paramtypes - The parameter types for method call, null = parameterless method

args - The arguments for method call

Returns:

Method return valiu, null otherwise (also if errors did occur)

invokeStatic

public static Object invokeStatic(String classname,
                                  String methodname,
                                  String[] paramtypes,
                                  Object... args)

Invokes a static (class) method using reflection.

Parameters:

classname - The class to be accessed

methodname - The method to be invoked

paramtypes - The parameter types for method call, null = parameterless method

args - The arguments for method call

Returns:

Method return value, null otherwise (also if errors did occur)

Since:

2.8

getStaticField

public static Object getStaticField(String classname,
                                    String fieldname)

Extracts the value of the static field via reflection (only public).

Parameters:

classname - The class name to be accessed

fieldname - The name of the field to access

Returns:

Static field value, may be null

Throws:

NullPointerException - If the parameters are null

ClassNotFoundException - Error indication

NoSuchFieldException - Error indication

IllegalAccessException - Error indication

Since:

2.8