001// Copyright 2008-2013 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; 016 017import java.io.IOException; 018import java.io.Serializable; 019import java.util.concurrent.atomic.AtomicBoolean; 020 021/** 022 * Base implementation of 023 * {@link org.apache.tapestry5.OptimizedSessionPersistedObject}. Subclasses 024 * should invoke {@link #markDirty()} after the internal state of the object changes. 025 * <p> 026 * Due to the concurrent nature of session attributes it's important that markDirty occurs <strong>after</strong> 027 * the object has been changed. If the change occurs before the object has been mutated it's possible that another 028 * thread may re-store the object before the changes are actually made! 029 * <p> 030 * @since 5.1.1.0 031 */ 032public abstract class BaseOptimizedSessionPersistedObject implements OptimizedSessionPersistedObject, Serializable 033{ 034 private static final long serialVersionUID = 172352928643322125L; 035 036 private transient AtomicBoolean dirty = new AtomicBoolean(false); 037 038 private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException { 039 dirty = new AtomicBoolean(false); 040 } 041 042 public final boolean checkAndResetDirtyMarker() 043 { 044 return dirty.getAndSet(false); 045 } 046 047 /** 048 * Invoked by the subclass after internal state of the object changes. 049 */ 050 protected final void markDirty() 051 { 052 dirty.set(true); 053 } 054}