001    // Copyright 2011 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.internal.jpa;
016    
017    import org.apache.tapestry5.internal.services.SessionApplicationStatePersistenceStrategy;
018    import org.apache.tapestry5.jpa.EntityManagerManager;
019    import org.apache.tapestry5.services.ApplicationStateCreator;
020    import org.apache.tapestry5.services.Request;
021    
022    public class EntityApplicationStatePersistenceStrategy extends
023            SessionApplicationStatePersistenceStrategy
024    {
025        private final EntityManagerManager entityManagerManager;
026    
027        public EntityApplicationStatePersistenceStrategy(final Request request,
028                final EntityManagerManager entityManagerManager)
029        {
030            super(request);
031    
032            this.entityManagerManager = entityManagerManager;
033        }
034    
035        @Override
036        public <T> T get(final Class<T> ssoClass, final ApplicationStateCreator<T> creator)
037        {
038            final Object persistedValue = getOrCreate(ssoClass, creator);
039    
040            if (persistedValue instanceof PersistedEntity)
041            {
042                final PersistedEntity persisted = (PersistedEntity) persistedValue;
043    
044                final Object restored = persisted.restore(entityManagerManager);
045    
046                // shall we maybe throw an exception instead?
047                if (restored == null)
048                {
049                    set(ssoClass, null);
050                    return (T) getOrCreate(ssoClass, creator);
051                }
052    
053                return (T) restored;
054            }
055    
056            return (T) persistedValue;
057        }
058    
059        @Override
060        public <T> void set(final Class<T> ssoClass, final T sso)
061        {
062            final String key = buildKey(ssoClass);
063    
064            Object entity;
065    
066            if (sso != null)
067            {
068                try
069                {
070                    entity = JpaInternalUtils.convertApplicationValueToPersisted(entityManagerManager,
071                            sso);
072                }
073                catch (final RuntimeException ex)
074                {
075                    // if entity not attached to an EntityManager yet, store it as usual sso
076                    entity = sso;
077                }
078            }
079            else
080            {
081                entity = sso;
082            }
083    
084            getSession().setAttribute(key, entity);
085        }
086    
087    }