    001    // Copyright 2009 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    package org.apache.tapestry5.internal.hibernate;
    015
    016    import java.io.Serializable;
    017
    018    import org.apache.tapestry5.internal.services.SessionApplicationStatePersistenceStrategy;
    019    import org.apache.tapestry5.services.ApplicationStateCreator;
    020    import org.apache.tapestry5.services.Request;
    021    import org.hibernate.HibernateException;
    022
    023    /**
    024     * Persists Hibernate entities as SSOs by storing their primary key in the {@link org.apache.tapestry5.services.Session}.
    025     *
    026     * @see org.apache.tapestry5.internal.hibernate.PersistedEntity
    027     */
    028    public class EntityApplicationStatePersistenceStrategy extends SessionApplicationStatePersistenceStrategy
    029    {
    030
    031            private final org.hibernate.Session hibernateSession;
    032
    033            public EntityApplicationStatePersistenceStrategy(Request request, org.hibernate.Session hibernateSession)
    034            {
    035                    super(request);
    036                    this.hibernateSession = hibernateSession;
    037            }
    038
    039            @SuppressWarnings("unchecked")
    040            public <T> T get(Class<T> ssoClass, ApplicationStateCreator<T> creator)
    041            {
    042                    final Object persistedValue =  getOrCreate(ssoClass, creator);
    043
    044                    if(persistedValue instanceof PersistedEntity)
    045                    {
    046                            final PersistedEntity persisted = (PersistedEntity) persistedValue;
    047
    048                            Object restored = persisted.restore(this.hibernateSession);
    049
    050                            //shall we maybe throw an exception instead?
    051                            if(restored == null)
    052                            {
    053                                    set(ssoClass, null);
    054                                    return (T) getOrCreate(ssoClass, creator);
    055                            }
    056
    057                            return (T) restored;
    058                    }
    059
    060                    return (T) persistedValue;
    061            }
    062
    063            public <T> void set(Class<T> ssoClass, T sso)
    064            {
    065                    final String key = buildKey(ssoClass);
    066                    Object entity;
    067
    068                    if(sso != null)
    069                    {
    070                            try
    071                            {
    072                                    final String entityName = this.hibernateSession.getEntityName(sso);
    073                                    final Serializable id = this.hibernateSession.getIdentifier(sso);
    074
    075                                    entity = new PersistedEntity(entityName, id);
    076                            }
    077                            catch (final HibernateException ex)
    078                            {
    079                                    // if entity not attached to a Hibernate Session yet, store it as usual sso
    080                                    entity = sso;
    081                            }
    082                    }
    083                    else
    084                    {
    085                            entity = sso;
    086                    }
    087
    088                    getSession().setAttribute(key, entity);
    089            }
    090
    091    }