    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}