Package org.apache.commons.lang.reflect

Class 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 1057009 2011-01-09 19:48:06Z niallp $

    • 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 respecting 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,
                                     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,
                               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,
                                    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,
                              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,
                              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