    001// Copyright 2006 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.services;
    016
    017/**
    018 * Represents a previously stored change to a persistent field, within the context of a particular page of the
    019 * application.
    020 */
    021public interface PersistentFieldChange
    022{
    023    /**
    024     * Returns the nested id of the component, or the empty string for the page's root component.
    025     */
    026    String getComponentId();
    027
    028    /**
    029     * Returns the name of the field for which a change was recorded.
    030     */
    031    String getFieldName();
    032
    033    /**
    034     * Returns the new value for the field (which may be null).
    035     */
    036    Object getValue();
    037}