/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.lang3.reflect;

import org.apache.commons.lang3.ClassUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.List;

/**
 * Utilities for working with {@link Field}s by reflection. Adapted and refactored from the dormant [reflect] Commons sandbox
 * component.
 * <p>
 * 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 1546799 2013-12-01 10:34:02Z mcucchiara $
 */
public class FieldUtils {

    /**
     * {@link FieldUtils} instances should NOT be constructed in standard programming.
     * <p>
     * This constructor is {@code public} to permit tools that require a JavaBean instance to operate.</p>
     */
    public FieldUtils() {
        super();
    }

    /**
     * Gets an accessible {@link Field} by name respecting scope. Superclasses/interfaces will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty
     */
    public static Field getField(final Class<?> cls, final String fieldName) {
        final Field field = getField(cls, fieldName, false);
        MemberUtils.setAccessibleWorkaround(field);
        return field;
    }

    /**
     * Gets an accessible {@link Field} by name, breaking scope if requested. Superclasses/interfaces will be
     * considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty or is matched at
     *             multiple places in the inheritance hierarchy
     */
    public static Field getField(final Class<?> cls, final String fieldName, final boolean forceAccess) {
        Validate.isTrue(cls != null, "The class must not be null");
        Validate.isTrue(StringUtils.isNotBlank(fieldName), "The field name must not be blank/empty");
        // Sun Java 1.3 has a bugged implementation of getField hence we write the
        // code ourselves

        // getField() will return the Field object with the declaring class
        // set correctly to the class that declares the field. Thus requesting the
        // field on a subclass will return the field from the superclass.
        //
        // priority order for lookup:
        // searchclass private/protected/package/public
        // superclass protected/package/public
        // private/different package blocks access to further superclasses
        // implementedinterface public

        // check up the superclass hierarchy
        for (Class<?> acls = cls; acls != null; acls = acls.getSuperclass()) {
            try {
                final Field field = acls.getDeclaredField(fieldName);
                // getDeclaredField checks for non-public scopes as well
                // and it returns accurate results
                if (!Modifier.isPublic(field.getModifiers())) {
                    if (forceAccess) {
                        field.setAccessible(true);
                    } else {
                        continue;
                    }
                }
                return field;
            } catch (final NoSuchFieldException ex) { // NOPMD
                // ignore
            }
        }
        // check the public interface case. This must be manually searched for
        // incase there is a public supersuperclass field hidden by a private/package
        // superclass field.
        Field match = null;
        for (final Class<?> class1 : ClassUtils.getAllInterfaces(cls)) {
            try {
                final Field test = class1.getField(fieldName);
                Validate.isTrue(match == null, "Reference to field %s is ambiguous relative to %s"
                        + "; a matching field exists on two or more implemented interfaces.", fieldName, cls);
                match = test;
            } catch (final NoSuchFieldException ex) { // NOPMD
                // ignore
            }
        }
        return match;
    }

    /**
     * Gets an accessible {@link Field} by name respecting scope. Only the specified class will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty
     */
    public static Field getDeclaredField(final Class<?> cls, final String fieldName) {
        return getDeclaredField(cls, fieldName, false);
    }

    /**
     * Gets an accessible {@link Field} by name, breaking scope if requested. Only the specified class will be
     * considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty
     */
    public static Field getDeclaredField(final Class<?> cls, final String fieldName, final boolean forceAccess) {
        Validate.isTrue(cls != null, "The class must not be null");
        Validate.isTrue(StringUtils.isNotBlank(fieldName), "The field name must not be blank/empty");
        try {
            // only consider the specified class by using getDeclaredField()
            final Field field = cls.getDeclaredField(fieldName);
            if (!MemberUtils.isAccessible(field)) {
                if (forceAccess) {
                    field.setAccessible(true);
                } else {
                    return null;
                }
            }
            return field;
        } catch (final NoSuchFieldException e) { // NOPMD
            // ignore
        }
        return null;
    }

    /**
     * Gets all fields of the given class and its parents (if any).
     * 
     * @param cls
     *            the {@link Class} to query
     * @return an array of Fields (possibly empty).
     * @throws IllegalArgumentException
     *             if the class is {@code null}
     * @since 3.2
     */
    public static Field[] getAllFields(Class<?> cls) {
        final List<Field> allFieldsList = getAllFieldsList(cls);
        return allFieldsList.toArray(new Field[allFieldsList.size()]);
    }

    /**
     * Gets all fields of the given class and its parents (if any).
     * 
     * @param cls
     *            the {@link Class} to query
     * @return an array of Fields (possibly empty).
     * @throws IllegalArgumentException
     *             if the class is {@code null}
     * @since 3.2
     */
    public static List<Field> getAllFieldsList(Class<?> cls) {
        Validate.isTrue(cls != null, "The class must not be null");
        final List<Field> allFields = new ArrayList<Field>();
        Class<?> currentClass = cls;
        while (currentClass != null) {
            final Field[] declaredFields = currentClass.getDeclaredFields();
            for (Field field : declaredFields) {
                allFields.add(field);
            }
            currentClass = currentClass.getSuperclass();
        }
        return allFields;
    }

    /**
     * Reads an accessible {@code static} {@link Field}.
     * 
     * @param field
     *            to read
     * @return the field value
     * @throws IllegalArgumentException
     *             if the field is {@code null}, or not {@code static}
     * @throws IllegalAccessException
     *             if the field is not accessible
     */
    public static Object readStaticField(final Field field) throws IllegalAccessException {
        return readStaticField(field, false);
    }

    /**
     * Reads a static {@link Field}.
     * 
     * @param field
     *            to read
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     * @return the field value
     * @throws IllegalArgumentException
     *             if the field is {@code null} or not {@code static}
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static Object readStaticField(final Field field, final boolean forceAccess) throws IllegalAccessException {
        Validate.isTrue(field != null, "The field must not be null");
        Validate.isTrue(Modifier.isStatic(field.getModifiers()), "The field '%s' is not static", field.getName());
        return readField(field, (Object) null, forceAccess);
    }

    /**
     * Reads the named {@code public static} {@link Field}. Superclasses will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the value of the field
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty,
     *             is not {@code static}, or could not be found
     * @throws IllegalAccessException
     *             if the field is not accessible
     */
    public static Object readStaticField(final Class<?> cls, final String fieldName) throws IllegalAccessException {
        return readStaticField(cls, fieldName, false);
    }

    /**
     * Reads the named {@code static} {@link Field}. Superclasses will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty,
     *             is not {@code static}, or could not be found
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static Object readStaticField(final Class<?> cls, final String fieldName, final boolean forceAccess) throws IllegalAccessException {
        final Field field = getField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate field '%s' on %s", fieldName, cls);
        // already forced access above, don't repeat it here:
        return readStaticField(field, false);
    }

    /**
     * Gets the value of a {@code static} {@link Field} by name. The field must be {@code public}.
     * Only the specified class will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the value of the field
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty,
     *             is not {@code static}, or could not be found
     * @throws IllegalAccessException
     *             if the field is not accessible
     */
    public static Object readDeclaredStaticField(final Class<?> cls, final String fieldName) throws IllegalAccessException {
        return readDeclaredStaticField(cls, fieldName, false);
    }

    /**
     * Gets the value of a {@code static} {@link Field} by name.
     * Only the specified class will be considered.
     * 
     * @param cls
     *            the {@link Class} to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @return the Field object
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or the field name is blank or empty,
     *             is not {@code static}, or could not be found
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static Object readDeclaredStaticField(final Class<?> cls, final String fieldName, final boolean forceAccess) throws IllegalAccessException {
        final Field field = getDeclaredField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
        // already forced access above, don't repeat it here:
        return readStaticField(field, false);
    }

    /**
     * Reads an accessible {@link Field}.
     * 
     * @param field
     *            the field to use
     * @param target
     *            the object to call on, may be {@code null} for {@code static} fields
     * @return the field value
     * @throws IllegalArgumentException
     *             if the field is {@code null}
     * @throws IllegalAccessException
     *             if the field is not accessible
     */
    public static Object readField(final Field field, final Object target) throws IllegalAccessException {
        return readField(field, target, false);
    }

    /**
     * Reads a {@link Field}.
     * 
     * @param field
     *            the field to use
     * @param target
     *            the object to call on, may be {@code null} for {@code static} fields
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     * @return the field value
     * @throws IllegalArgumentException
     *             if the field is {@code null}
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static Object readField(final Field field, final Object target, final boolean forceAccess) throws IllegalAccessException {
        Validate.isTrue(field != null, "The field must not be null");
        if (forceAccess && !field.isAccessible()) {
            field.setAccessible(true);
        } else {
            MemberUtils.setAccessibleWorkaround(field);
        }
        return field.get(target);
    }

    /**
     * Reads the named {@code public} {@link Field}. Superclasses will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the value of the field
     * @throws IllegalArgumentException
     *             if the class is {@code null}, or
     *             the field name is blank or empty or could not be found
     * @throws IllegalAccessException
     *             if the named field is not {@code public}
     */
    public static Object readField(final Object target, final String fieldName) throws IllegalAccessException {
        return readField(target, fieldName, false);
    }

    /**
     * Reads the named {@link Field}. Superclasses will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @return the field value
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null}, or
     *             the field name is blank or empty or could not be found
     * @throws IllegalAccessException
     *             if the named field is not made accessible
     */
    public static Object readField(final Object target, final String fieldName, final boolean forceAccess) throws IllegalAccessException {
        Validate.isTrue(target != null, "target object must not be null");
        final Class<?> cls = target.getClass();
        final Field field = getField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate field %s on %s" , fieldName, cls);
        // already forced access above, don't repeat it here:
        return readField(field, target);
    }

    /**
     * Reads the named {@code public} {@link Field}. Only the class of the specified object will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @return the value of the field
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null}, or
     *             the field name is blank or empty or could not be found
     * @throws IllegalAccessException
     *             if the named field is not {@code public}
     */
    public static Object readDeclaredField(final Object target, final String fieldName) throws IllegalAccessException {
        return readDeclaredField(target, fieldName, false);
    }

    /**
     * <p<>Gets a {@link Field} value by name. Only the class of the specified object will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match public fields.
     * @return the Field object
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null}, or
     *             the field name is blank or empty or could not be found
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static Object readDeclaredField(final Object target, final String fieldName, final boolean forceAccess) throws IllegalAccessException {
        Validate.isTrue(target != null, "target object must not be null");
        final Class<?> cls = target.getClass();
        final Field field = getDeclaredField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate declared field %s.%s" , cls, fieldName);
        // already forced access above, don't repeat it here:
        return readField(field, target);
    }

    /**
     * Writes a {@code public static} {@link Field}.
     * 
     * @param field
     *            to write
     * @param value
     *            to set
     * @throws IllegalArgumentException
     *             if the field is {@code null} or not {@code static},
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not {@code public} or is {@code final}
     */
    public static void writeStaticField(final Field field, final Object value) throws IllegalAccessException {
        writeStaticField(field, value, false);
    }

    /**
     * Writes a static {@link Field}.
     * 
     * @param field
     *            to write
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method. {@code false}
     *            will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if the field is {@code null} or not {@code static},
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible or is {@code final}
     */
    public static void writeStaticField(final Field field, final Object value, final boolean forceAccess) throws IllegalAccessException {
        Validate.isTrue(field != null, "The field must not be null");
        Validate.isTrue(Modifier.isStatic(field.getModifiers()), "The field %s.%s is not static",
                field.getDeclaringClass().getName(), field.getName());
        writeField(field, (Object) null, value, forceAccess);
    }

    /**
     * Writes a named {@code public static} {@link Field}. Superclasses will be considered.
     * 
     * @param cls
     *            {@link Class} on which the field is to be found
     * @param fieldName
     *            to write
     * @param value
     *            to set
     * @throws IllegalArgumentException
     *             if {@code cls} is {@code null},
     *             the field name is blank or empty,
     *             the field cannot be located or is not {@code static}, or
     *             {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not {@code public} or is {@code final}
     */
    public static void writeStaticField(final Class<?> cls, final String fieldName, final Object value) throws IllegalAccessException {
        writeStaticField(cls, fieldName, value, false);
    }

    /**
     * Writes a named {@code static} {@link Field}. Superclasses will be considered.
     * 
     * @param cls
     *            {@link Class} on which the field is to be found
     * @param fieldName
     *            to write
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if {@code cls} is {@code null},
     *             the field name is blank or empty,
     *             the field cannot be located or is not {@code static}, or
     *             {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible or is {@code final}
     */
    public static void writeStaticField(final Class<?> cls, final String fieldName, final Object value, final boolean forceAccess)
            throws IllegalAccessException {
        final Field field = getField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate field %s on %s", fieldName, cls);
        // already forced access above, don't repeat it here:
        writeStaticField(field, value);
    }

    /**
     * Writes a named {@code public static} {@link Field}. Only the specified class will be considered.
     * 
     * @param cls
     *            {@link Class} on which the field is to be found
     * @param fieldName
     *            to write
     * @param value
     *            to set
     * @throws IllegalArgumentException
     *             if {@code cls} is {@code null},
     *             the field name is blank or empty,
     *             the field cannot be located or is not {@code static}, or
     *             {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not {@code public} or is {@code final}
     */
    public static void writeDeclaredStaticField(final Class<?> cls, final String fieldName, final Object value) throws IllegalAccessException {
        writeDeclaredStaticField(cls, fieldName, value, false);
    }

    /**
     * Writes a named {@code static} {@link Field}. Only the specified class will be considered.
     * 
     * @param cls
     *            {@link Class} on which the field is to be found
     * @param fieldName
     *            to write
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the {@code AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if {@code cls} is {@code null},
     *             the field name is blank or empty,
     *             the field cannot be located or is not {@code static}, or
     *             {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible or is {@code final}
     */
    public static void writeDeclaredStaticField(final Class<?> cls, final String fieldName, final Object value, final boolean forceAccess)
            throws IllegalAccessException {
        final Field field = getDeclaredField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
        // already forced access above, don't repeat it here:
        writeField(field, (Object) null, value);
    }

    /**
     * Writes an accessible {@link Field}.
     * 
     * @param field
     *            to write
     * @param target
     *            the object to call on, may be {@code null} for {@code static} fields
     * @param value
     *            to set
     * @throws IllegalAccessException
     *             if the field or target is {@code null},
     *             the field is not accessible or is {@code final}, or
     *             {@code value} is not assignable
     */
    public static void writeField(final Field field, final Object target, final Object value) throws IllegalAccessException {
        writeField(field, target, value, false);
    }

    /**
     * Writes a {@link Field}.
     * 
     * @param field
     *            to write
     * @param target
     *            the object to call on, may be {@code null} for {@code static} fields
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if the field is {@code null} or
     *             {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible or is {@code final}
     */
    public static void writeField(final Field field, final Object target, final Object value, final boolean forceAccess)
            throws IllegalAccessException {
        Validate.isTrue(field != null, "The field must not be null");
        if (forceAccess && !field.isAccessible()) {
            field.setAccessible(true);
        } else {
            MemberUtils.setAccessibleWorkaround(field);
        }
        field.set(target, value);
    }

    /**
     * Remove the final modifier from a {@link Field}
     * @param field to remove the final modifier
     * @throws IllegalArgumentException
     *             if the field is {@code null}
     */
    public static void removeFinalModifier(Field field)  {
        Validate.isTrue(field != null, "The field must not be null");

        try {
            if(Modifier.isFinal(field.getModifiers())){
                Field modifiersField = Field.class.getDeclaredField("modifiers");
                modifiersField.setAccessible(true);
                modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL);
            }
        } catch (NoSuchFieldException ignored) {
            // The field class contains always a modifiers field
        } catch (IllegalAccessException ignored) {
             // The modifiers field is made accessible
        }
    }

    /**
     * Writes a {@code public} {@link Field}. Superclasses will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param value
     *            to set
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null},
     *             {@code fieldName} is blank or empty or could not be found,
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not accessible
     */
    public static void writeField(final Object target, final String fieldName, final Object value) throws IllegalAccessException {
        writeField(target, fieldName, value, false);
    }

    /**
     * Writes a {@link Field}. Superclasses will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method. {@code false}
     *            will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null},
     *             {@code fieldName} is blank or empty or could not be found,
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static void writeField(final Object target, final String fieldName, final Object value, final boolean forceAccess)
            throws IllegalAccessException {
        Validate.isTrue(target != null, "target object must not be null");
        final Class<?> cls = target.getClass();
        final Field field = getField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
        // already forced access above, don't repeat it here:
        writeField(field, target, value);
    }

    /**
     * Writes a {@code public} {@link Field}. Only the specified class will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param value
     *            to set
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null},
     *             {@code fieldName} is blank or empty or could not be found,
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static void writeDeclaredField(final Object target, final String fieldName, final Object value) throws IllegalAccessException {
        writeDeclaredField(target, fieldName, value, false);
    }

    /**
     * Writes a {@code public} {@link Field}. Only the specified class will be considered.
     * 
     * @param target
     *            the object to reflect, must not be {@code null}
     * @param fieldName
     *            the field name to obtain
     * @param value
     *            to set
     * @param forceAccess
     *            whether to break scope restrictions using the
     *            {@link java.lang.reflect.AccessibleObject#setAccessible(boolean)} method.
     *            {@code false} will only match {@code public} fields.
     * @throws IllegalArgumentException
     *             if {@code target} is {@code null},
     *             {@code fieldName} is blank or empty or could not be found,
     *             or {@code value} is not assignable
     * @throws IllegalAccessException
     *             if the field is not made accessible
     */
    public static void writeDeclaredField(final Object target, final String fieldName, final Object value, final boolean forceAccess)
            throws IllegalAccessException {
        Validate.isTrue(target != null, "target object must not be null");
        final Class<?> cls = target.getClass();
        final Field field = getDeclaredField(cls, fieldName, forceAccess);
        Validate.isTrue(field != null, "Cannot locate declared field %s.%s", cls.getName(), fieldName);
        // already forced access above, don't repeat it here:
        writeField(field, target, value);
    }
}