    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}