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 }