    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
    015    package 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     */
    021    public 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    }