    001// Copyright 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.plastic;
    016
    017/**
    018 * Allows read/write access directly to a field (bypassing accessors). Does not use reflection, even
    019 * if the field is private (the normal case for Plastic classes).
    020 */
    021public interface FieldHandle
    022{
    023    /**
    024     * Gets the current value of the field. If the field is a primitive value, then the primitive
    025     * will be wrapped.
    026     *
    027     * @throws NullPointerException
    028     *             if the instance is null
    029     * @throws ClassCastException
    030     *             if the instance is not the type that contains the field
    031     */
    032    Object get(Object instance);
    033
    034    /**
    035     * Updates the current value of the field. If the field is a primitive value, then the newValue
    036     * will be unwrapped automatically.
    037     *
    038     * @throws NullPointerException
    039     *             if the instance is null
    040     * @throws NullPointerException
    041     *             if the newValue is null and the field is a primitive type
    042     * @throws ClassCastException
    043     *             if the instance is not the type that contains the field
    044     * @throws ClassCastException
    045     *             if the newValue is not assignable to the field type (or not the matching wrapper type
    046     *             for a primitive field)
    047     */
    048    void set(Object instance, Object newValue);
    049}