001// Copyright 2006, 2007, 2008 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.internal.services;
016
017import org.apache.tapestry5.ComponentResources;
018import org.apache.tapestry5.ioc.annotations.UsesMappedConfiguration;
019import org.apache.tapestry5.services.PersistentFieldBundle;
020import org.apache.tapestry5.services.PersistentFieldStrategy;
021
022/**
023 * Handle persistent property changes. Primarily, delegates to a number of {@link org.apache.tapestry5.services.PersistentFieldStrategy}
024 * instances.
025 */
026@UsesMappedConfiguration(PersistentFieldStrategy.class)
027public interface PersistentFieldManager
028{
029    /**
030     * Posts a change of a persistent property.
031     *
032     * @param pageName  the logical name of the page containing the component
033     * @param resources the resources for the component or mixin (used to determine the persistence strategy)
034     * @param fieldName the name of the field whose persistent value has changed
035     * @param newValue  the new value for the field, possibly null
036     */
037    void postChange(String pageName, ComponentResources resources, String fieldName, Object newValue);
038
039    /**
040     * Locates all persistently stored changes to all properties within the page (for the current session and request)
041     * and gathers them together into a bundle.
042     *
043     * @param pageName the logical name of the page to gather changes for
044     * @return a bundle identifying all such changes
045     */
046    PersistentFieldBundle gatherChanges(String pageName);
047
048    /**
049     * Discards all changes for the indicated page. This will not affect pages that have already been attached to this
050     * request, but will affect subsequent page attachments in this and later requests.
051     *
052     * @param pageName logical name of page whose persistent field data is to be discarded
053     */
054    void discardChanges(String pageName);
055    
056    /**
057     * Discards changes on the indicated page for a specific strategy only. This will not affect pages that have already 
058     * been attached to this request, but will affect subsequent page attachments in this and later requests.
059     *
060     * @param pageName logical name of page whose persistent field data is to be discarded
061     * 
062     * @param strategyName name of the strategy of which field data is to be discarded
063     */
064    void discardChanges(String pageName, String strategyName);
065    
066}