org.apache.commons.lang.reflect
Class FieldUtils

java.lang.Object
  org.apache.commons.lang.reflect.FieldUtils

public class FieldUtils
extends Object

Utilities for working with fields by reflection. Adapted and refactored from the dormant [reflect] Commons sandbox component.

The ability is provided to break the scoping restrictions coded by the programmer. This can allow fields to be changed that shouldn't be. This facility should be used with care.

Since:

2.5

Version:

$Id: FieldUtils.java 905636 2010-02-02 14:03:32Z niallp $

Author:

Apache Software Foundation, Matt Benson

Constructor Summary

FieldUtils()
FieldUtils instances should NOT be constructed in standard programming.

Method Summary

static Field	getDeclaredField(Class cls, String fieldName) Gets an accessible Field by name respecting scope.
static Field	getDeclaredField(Class cls, String fieldName, boolean forceAccess) Gets an accessible Field by name breaking scope if requested.
static Field	getField(Class cls, String fieldName) Gets an accessible Field by name repecting scope.
static Field	getField(Class cls, String fieldName, boolean forceAccess) Gets an accessible Field by name breaking scope if requested.
static Object	readDeclaredField(Object target, String fieldName) Read the named public field.
static Object	readDeclaredField(Object target, String fieldName, boolean forceAccess) Gets a Field value by name.
static Object	readDeclaredStaticField(Class cls, String fieldName) Gets a static Field value by name.
static Object	readDeclaredStaticField(Class cls, String fieldName, boolean forceAccess) Gets a static Field value by name.
static Object	readField(Field field, Object target) Read an accessible Field.
static Object	readField(Field field, Object target, boolean forceAccess) Read a Field.
static Object	readField(Object target, String fieldName) Read the named public field.
static Object	readField(Object target, String fieldName, boolean forceAccess) Read the named field.
static Object	readStaticField(Class cls, String fieldName) Read the named public static field.
static Object	readStaticField(Class cls, String fieldName, boolean forceAccess) Read the named static field.
static Object	readStaticField(Field field) Read an accessible static Field.
static Object	readStaticField(Field field, boolean forceAccess) Read a static Field.
static void	writeDeclaredField(Object target, String fieldName, Object value) Write a public field.
static void	writeDeclaredField(Object target, String fieldName, Object value, boolean forceAccess) Write a public field.
static void	writeDeclaredStaticField(Class cls, String fieldName, Object value) Write a named public static Field.
static void	writeDeclaredStaticField(Class cls, String fieldName, Object value, boolean forceAccess) Write a named static Field.
static void	writeField(Field field, Object target, Object value) Write an accessible field.
static void	writeField(Field field, Object target, Object value, boolean forceAccess) Write a field.
static void	writeField(Object target, String fieldName, Object value) Write a public field.
static void	writeField(Object target, String fieldName, Object value, boolean forceAccess) Write a field.
static void	writeStaticField(Class cls, String fieldName, Object value) Write a named public static Field.
static void	writeStaticField(Class cls, String fieldName, Object value, boolean forceAccess) Write a named static Field.
static void	writeStaticField(Field field, Object value) Write a public static Field.
static void	writeStaticField(Field field, Object value, boolean forceAccess) Write a static Field.

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldUtils

public FieldUtils()

FieldUtils instances should NOT be constructed in standard programming.

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

getField

public static Field getField(Class cls,
                             String fieldName)

Gets an accessible Field by name repecting scope. Superclasses/interfaces will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

getField

public static Field getField(Class cls,
                             String fieldName,
                             boolean forceAccess)

Gets an accessible Field by name breaking scope if requested. Superclasses/interfaces will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

getDeclaredField

public static Field getDeclaredField(Class cls,
                                     String fieldName)

Gets an accessible Field by name respecting scope. Only the specified class will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

getDeclaredField

public static Field getDeclaredField(Class cls,
                                     String fieldName,
                                     boolean forceAccess)

Gets an accessible Field by name breaking scope if requested. Only the specified class will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

readStaticField

public static Object readStaticField(Field field)
                              throws IllegalAccessException

Read an accessible static Field.

Parameters:

field - to read

Returns:

the field value

Throws:

IllegalArgumentException - if the field is null or not static

IllegalAccessException - if the field is not accessible

readStaticField

public static Object readStaticField(Field field,
                                     boolean forceAccess)
                              throws IllegalAccessException

Read a static Field.

Parameters:

field - to read

forceAccess - whether to break scope restrictions using the setAccessible method.

Returns:

the field value

Throws:

IllegalArgumentException - if the field is null or not static

IllegalAccessException - if the field is not made accessible

readStaticField

public static Object readStaticField(Class cls,
                                     String fieldName)
                              throws IllegalAccessException

Read the named public static field. Superclasses will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

Returns:

the value of the field

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the field is not accessible

readStaticField

public static Object readStaticField(Class cls,
                                     String fieldName,
                                     boolean forceAccess)
                              throws IllegalAccessException

Read the named static field. Superclasses will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the field is not made accessible

readDeclaredStaticField

public static Object readDeclaredStaticField(Class cls,
                                             String fieldName)
                                      throws IllegalAccessException

Gets a static Field value by name. The field must be public. Only the specified class will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

Returns:

the value of the field

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the field is not accessible

readDeclaredStaticField

public static Object readDeclaredStaticField(Class cls,
                                             String fieldName,
                                             boolean forceAccess)
                                      throws IllegalAccessException

Gets a static Field value by name. Only the specified class will be considered.

Parameters:

cls - the class to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the Field object

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the field is not made accessible

readField

public static Object readField(Field field,
                               Object target)
                        throws IllegalAccessException

Read an accessible Field.

Parameters:

field - the field to use

target - the object to call on, may be null for static fields

Returns:

the field value

Throws:

IllegalArgumentException - if the field is null

IllegalAccessException - if the field is not accessible

readField

public static Object readField(Field field,
                               Object target,
                               boolean forceAccess)
                        throws IllegalAccessException

Read a Field.

Parameters:

field - the field to use

target - the object to call on, may be null for static fields

forceAccess - whether to break scope restrictions using the setAccessible method.

Returns:

the field value

Throws:

IllegalArgumentException - if the field is null

IllegalAccessException - if the field is not made accessible

readField

public static Object readField(Object target,
                               String fieldName)
                        throws IllegalAccessException

Read the named public field. Superclasses will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

Returns:

the value of the field

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the named field is not public

readField

public static Object readField(Object target,
                               String fieldName,
                               boolean forceAccess)
                        throws IllegalAccessException

Read the named field. Superclasses will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the field value

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the named field is not made accessible

readDeclaredField

public static Object readDeclaredField(Object target,
                                       String fieldName)
                                throws IllegalAccessException

Read the named public field. Only the class of the specified object will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

Returns:

the value of the field

Throws:

IllegalArgumentException - if the class or field name is null

IllegalAccessException - if the named field is not public

readDeclaredField

public static Object readDeclaredField(Object target,
                                       String fieldName,
                                       boolean forceAccess)
                                throws IllegalAccessException

Gets a Field value by name. Only the class of the specified object will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Returns:

the Field object

Throws:

IllegalArgumentException - if target or fieldName is null

IllegalAccessException - if the field is not made accessible

writeStaticField

public static void writeStaticField(Field field,
                                    Object value)
                             throws IllegalAccessException

Write a public static Field.

Parameters:

field - to write

value - to set

Throws:

IllegalArgumentException - if the field is null or not static

IllegalAccessException - if the field is not public or is final

writeStaticField

public static void writeStaticField(Field field,
                                    Object value,
                                    boolean forceAccess)
                             throws IllegalAccessException

Write a static Field.

Parameters:

field - to write

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if the field is null or not static

IllegalAccessException - if the field is not made accessible or is final

writeStaticField

public static void writeStaticField(Class cls,
                                    String fieldName,
                                    Object value)
                             throws IllegalAccessException

Write a named public static Field. Superclasses will be considered.

Parameters:

cls - Class on which the Field is to be found

fieldName - to write

value - to set

Throws:

IllegalArgumentException - if the field cannot be located or is not static

IllegalAccessException - if the field is not public or is final

writeStaticField

public static void writeStaticField(Class cls,
                                    String fieldName,
                                    Object value,
                                    boolean forceAccess)
                             throws IllegalAccessException

Write a named static Field. Superclasses will be considered.

Parameters:

cls - Class on which the Field is to be found

fieldName - to write

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if the field cannot be located or is not static

IllegalAccessException - if the field is not made accessible or is final

writeDeclaredStaticField

public static void writeDeclaredStaticField(Class cls,
                                            String fieldName,
                                            Object value)
                                     throws IllegalAccessException

Write a named public static Field. Only the specified class will be considered.

Parameters:

cls - Class on which the Field is to be found

fieldName - to write

value - to set

Throws:

IllegalArgumentException - if the field cannot be located or is not static

IllegalAccessException - if the field is not public or is final

writeDeclaredStaticField

public static void writeDeclaredStaticField(Class cls,
                                            String fieldName,
                                            Object value,
                                            boolean forceAccess)
                                     throws IllegalAccessException

Write a named static Field. Only the specified class will be considered.

Parameters:

cls - Class on which the Field is to be found

fieldName - to write

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if the field cannot be located or is not static

IllegalAccessException - if the field is not made accessible or is final

writeField

public static void writeField(Field field,
                              Object target,
                              Object value)
                       throws IllegalAccessException

Write an accessible field.

Parameters:

field - to write

target - the object to call on, may be null for static fields

value - to set

Throws:

IllegalArgumentException - if the field is null

IllegalAccessException - if the field is not accessible or is final

writeField

public static void writeField(Field field,
                              Object target,
                              Object value,
                              boolean forceAccess)
                       throws IllegalAccessException

Write a field.

Parameters:

field - to write

target - the object to call on, may be null for static fields

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if the field is null

IllegalAccessException - if the field is not made accessible or is final

writeField

public static void writeField(Object target,
                              String fieldName,
                              Object value)
                       throws IllegalAccessException

Write a public field. Superclasses will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

value - to set

Throws:

IllegalArgumentException - if target or fieldName is null

IllegalAccessException - if the field is not accessible

writeField

public static void writeField(Object target,
                              String fieldName,
                              Object value,
                              boolean forceAccess)
                       throws IllegalAccessException

Write a field. Superclasses will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if target or fieldName is null

IllegalAccessException - if the field is not made accessible

writeDeclaredField

public static void writeDeclaredField(Object target,
                                      String fieldName,
                                      Object value)
                               throws IllegalAccessException

Write a public field. Only the specified class will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

value - to set

Throws:

IllegalArgumentException - if target or fieldName is null

IllegalAccessException - if the field is not made accessible

writeDeclaredField

public static void writeDeclaredField(Object target,
                                      String fieldName,
                                      Object value,
                                      boolean forceAccess)
                               throws IllegalAccessException

Write a public field. Only the specified class will be considered.

Parameters:

target - the object to reflect, must not be null

fieldName - the field name to obtain

value - to set

forceAccess - whether to break scope restrictions using the setAccessible method. False will only match public fields.

Throws:

IllegalArgumentException - if target or fieldName is null

IllegalAccessException - if the field is not made accessible