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
015package org.apache.tapestry5.internal.jpa;
016
017import org.apache.tapestry5.internal.services.SessionApplicationStatePersistenceStrategy;
018import org.apache.tapestry5.jpa.EntityManagerManager;
019import org.apache.tapestry5.services.ApplicationStateCreator;
020import org.apache.tapestry5.services.Request;
021
022public 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}