001// Copyright 2005 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.tapestry;
016
017import java.io.Serializable;
018
019import javax.servlet.http.HttpSessionBindingEvent;
020import javax.servlet.http.HttpSessionBindingListener;
021
022/**
023 * Base implementation of {@link org.apache.tapestry.SessionStoreOptimized}. Subclasses should
024 * invoke {@link #markSessionStoreNeeded()} any time internal state changed.
025 * 
026 * @author Howard M. Lewis Ship
027 * @since 4.0
028 */
029public class BaseSessionStoreOptimized implements SessionStoreOptimized, Serializable,
030        HttpSessionBindingListener
031{
032    private static final long serialVersionUID = -2786704444616789831L;
033
034    private transient boolean _dirty;
035
036    /**
037     * Clears the dirty flag.
038     */
039    public void valueBound(HttpSessionBindingEvent event)
040    {
041        _dirty = false;
042    }
043
044    /**
045     * Does nothing.
046     */
047    public void valueUnbound(HttpSessionBindingEvent event)
048    {
049    }
050
051    /**
052     * Sets the dirty flag.
053     */
054    protected void markSessionStoreNeeded()
055    {
056        _dirty = true;
057    }
058
059    /**
060     * Returns the dirty flag.
061     */
062    public boolean isStoreToSessionNeeded()
063    {
064        return _dirty;
065    }
066
067}