001// Copyright 2008, 2009, 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 015package org.apache.tapestry5; 016 017import java.util.concurrent.atomic.AtomicBoolean; 018 019/** 020 * Base implementation of 021 * {@link org.apache.tapestry5.OptimizedSessionPersistedObject}. Subclasses 022 * should invoke {@link #markDirty()} after the internal state of the object changes. 023 * <p> 024 * Due to the concurrent nature of session attributes it's important that markDirty occurs <strong>after</strong> 025 * the object has been changed. If the change occurs before the object has been mutated it's possible that another 026 * thread may re-store the object before the changes are actually made! 027 * <p> 028 * @since 5.1.1.0 029 */ 030public abstract class BaseOptimizedSessionPersistedObject implements OptimizedSessionPersistedObject 031{ 032 private transient AtomicBoolean dirty = new AtomicBoolean(false); 033 034 public final boolean checkAndResetDirtyMarker() 035 { 036 return dirty.getAndSet(false); 037 } 038 039 /** 040 * Invoked by the subclass after internal state of the object changes. 041 */ 042 protected final void markDirty() 043 { 044 dirty.set(true); 045 } 046}