Java Reflection Field Set setField(final O object, final String fieldName, final V value)

Description

Sets a field on an object, even if the field would not normally be accessible (such as a private field).

License

Open Source License

Parameter

Parameter	Description
O	the type of object to update.
V	the type of value to set.
object	the object.
fieldName	the name of the field to set.
value	the value to set.

Exception

Parameter	Description
SecurityException	if there is a problem getting the field of the object.
NoSuchFieldException	if the field does not exist.
IllegalAccessException	if the field cannot be accessed.
IllegalArgumentException	if the object is not a valid field.

Return

the old value.

Declaration

public final static <O, V> V setField(final O object, final String fieldName, final V value)
        throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException 

Method Source Code

//package com.java2s;
import java.lang.reflect.Field;

public class Main {
    /**/*from w  w  w  .  jav a  2  s.  co m*/
     * Sets a field on an object, even if the field would not normally be accessible (such as a private field).
     * <p>
     * 
     * @author Ian Andrew Brown
     * @param <O>
     *            the type of object to update.
     * @param <V>
     *            the type of value to set.
     * @param object
     *            the object.
     * @param fieldName
     *            the name of the field to set.
     * @param value
     *            the value to set.
     * @return the old value.
     * @throws SecurityException
     *             if there is a problem getting the field of the object.
     * @throws NoSuchFieldException
     *             if the field does not exist.
     * @throws IllegalAccessException
     *             if the field cannot be accessed.
     * @throws IllegalArgumentException
     *             if the object is not a valid field.
     * @since V2.2.0 Oct 4, 2014
     * @version V2.2.0 Oct 4, 2014
     */
    public final static <O, V> V setField(final O object, final String fieldName, final V value)
            throws NoSuchFieldException, SecurityException, IllegalArgumentException, IllegalAccessException {
        Field objectField = null;
        Class<?> workingClass = object.getClass();
        while (objectField == null) {
            try {
                objectField = workingClass.getDeclaredField(fieldName);
            } catch (final NoSuchFieldException e) {
                if (workingClass == Object.class) {
                    throw e;
                }
                workingClass = workingClass.getSuperclass();
            }
        }
        objectField.setAccessible(true);
        @SuppressWarnings("unchecked")
        final V oldValue = (V) objectField.get(object);
        objectField.set(object, value);
        return oldValue;
    }
}

Related

1. setField(Field field, Object target, Object value)
2. setField(Field field, T newValue, Object instance)
3. setField(Field field, U instance, Object value)
4. setField(final Field field, final Object instance, final Object value)
5. setField(final Field field, final Object object, final Object value)
6. setField(final Object instance, final String fieldName, final T value)
7. setField(final Object obj, final String fieldName, final int value)
8. setField(final Object obj, final String fieldName, final Object value)
9. setField(final Object obj, final String name, final Object value)