001    // Copyright 2007, 2008 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.hibernate;
016    
017    import org.hibernate.Session;
018    
019    /**
020     * Manages the Hibernate session for the current thread. This includes creating the session as needed, allowing the
021     * session to checkpoint (commit the current transaction and continue) and commit the transaction automatically at the
022     * end of the request.
023     * <p/>
024     * Remember that in Tapestry, action requests and render requests are entirely separate, and you will see a separate
025     * request and a separate transaction for each. Care should be taken to ensure that entity objects that are retained (in
026     * the session, as persistent field values) between requests are handled correctly (they tend to become detached
027     * instances).
028     * <p/>
029     * This implementation of this service is per-thread.
030     */
031    public interface HibernateSessionManager
032    {
033        /**
034         * Gets the active session for this request, creating it as necessary. When the session is first created, a
035         * transaction is started.
036         *
037         * @return the request's session
038         * @see HibernateSessionSource
039         */
040        Session getSession();
041    
042        /**
043         * Commits the current transaction (which will cause a flush of data to the database), then starts a new transaction
044         * to replace it.
045         */
046        void commit();
047    
048        /**
049         * Aborts the current transaction, and starts a new transaction to replace it.
050         */
051        void abort();
052    }