    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.http.services.Request;
    018import org.apache.tapestry5.internal.services.SessionApplicationStatePersistenceStrategy;
    019import org.apache.tapestry5.jpa.EntityManagerManager;
    020import org.apache.tapestry5.services.ApplicationStateCreator;
    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    protected <T> T transformPersistedValue(Object value)
    037    {
    038        return value instanceof PersistedEntity ? (T) ((PersistedEntity) value).restore(entityManagerManager) : (T) value;
    039    }
    040
    041    @Override
    042    public <T> T get(final Class<T> ssoClass, final ApplicationStateCreator<T> creator)
    043    {
    044        final Object persistedValue = getOrCreate(ssoClass, creator);
    045
    046        if (persistedValue instanceof PersistedEntity)
    047        {
    048            final PersistedEntity persisted = (PersistedEntity) persistedValue;
    049
    050            final Object restored = transformPersistedValue(persisted);
    051
    052            // shall we maybe throw an exception instead?
    053            if (restored == null)
    054            {
    055                set(ssoClass, null);
    056                return (T) getOrCreate(ssoClass, creator);
    057            }
    058
    059            return (T) restored;
    060        }
    061
    062        return (T) persistedValue;
    063    }
    064
    065    @Override
    066    public <T> void set(final Class<T> ssoClass, final T sso)
    067    {
    068        final String key = buildKey(ssoClass);
    069
    070        Object entity;
    071
    072        if (sso != null)
    073        {
    074            try
    075            {
    076                entity = JpaInternalUtils.convertApplicationValueToPersisted(entityManagerManager,
    077                        sso);
    078            }
    079            catch (final RuntimeException ex)
    080            {
    081                // if entity not attached to an EntityManager yet, store it as usual sso
    082                entity = sso;
    083            }
    084        }
    085        else
    086        {
    087            entity = sso;
    088        }
    089
    090        getSession().setAttribute(key, entity);
    091    }
    092
    093}