001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005//     http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.hibernate;
014
015import org.hibernate.Session;
016
017/**
018 * Manages the Hibernate session for the current thread. This includes creating the session as needed, allowing the
019 * session to checkpoint (commit the current transaction and continue) and commit the transaction automatically at the
020 * end of the request.
021 *
022 * Remember that in Tapestry, action requests and render requests are entirely separate, and you will see a separate
023 * request and a separate transaction for each. Care should be taken to ensure that entity objects that are retained (in
024 * the session, as persistent field values) between requests are handled correctly (they tend to become detached
025 * instances).
026 *
027 * This implementation of this service is per-thread.
028 */
029public interface HibernateSessionManager
030{
031    /**
032     * Gets the active session for this request, creating it as necessary. When the session is first created, a
033     * transaction is started.
034     *
035     * @return the request's session
036     * @see HibernateSessionSource
037     */
038    Session getSession();
039
040    /**
041     * Commits the current transaction (which will cause a flush of data to the database), then starts a new transaction
042     * to replace it.
043     */
044    void commit();
045
046    /**
047     * Aborts the current transaction, and starts a new transaction to replace it.
048     */
049    void abort();
050}