    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
    015    package 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     */
    030    public 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    }