hlship-20080520/tapestry-hibernate/src/main/java/org/apache/tapestry/hibernate/HibernateSessionManager.java

// Copyright 2007 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.hibernate;

import org.hibernate.Session;

/**
 * Manages the Hibernate session for the current thread. This includes creating the session as
 * needed, allowing the session to checkpoint (commit the current transaction and continue) and
 * commit the transaction automatically at the end of the request.
 * <p>
 * Remember that in Tapestry, action requests and render requests are entirely separate, and you
 * will see a separate request and a separate transaction for each. Care should be taken to ensure
 * that entity objects that are retained (in the session, as persistent field values) between
 * requests are handled correctly (they tend to become detached instances).
 * <p>
 * This implementation of this service is per-thread.
 */
public interface HibernateSessionManager
{
  /**
   * Gets the active session for this request, creating it as necessary. When the session is first
   * created, a transaction is started.
   * 
   * @return the request's session
   * @see HibernateSessionSource
   */
  Session getSession();

  /**
   * Commits the current transaction (which will cause a flush of data to the database), then starts
   * a new transaction to replace it.
   */
  void commit();

  /**
   * Aborts the current transaction, and starts a new transaction to replace it.
   */
  void abort();
}