001// Copyright 2008, 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
017/**
018 * An optional interface implemented by objects that are persisted in the {@link org.apache.tapestry5.services.Session}.
019 * At the end of each request, any objects read from the session are re-stored into the session, to ensure that
020 * in-memory changes are flushed to other persistent session stores (e.g. RDBMS, servers in a cluster, etc). Objects
021 * that implement this interface are expected to track when they are dirty (have pending changes), so that the save
022 * back into the session can be avoided when not necessary.
023 * <p>
024 * This method is accessed concurrently.
025 *
026 * @see org.apache.tapestry5.annotations.ImmutableSessionPersistedObject
027 * @see org.apache.tapestry5.services.SessionPersistedObjectAnalyzer
028 * @since 5.1.1.0
029 */
030public interface OptimizedSessionPersistedObject
031{
032    /**
033     * @return true if the object has in-memory changes since the last time this method was called.
034     */
035    boolean checkAndResetDirtyMarker();
036}