001// Copyright 2009, 2014 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.hibernate.web.internal;
016
017import org.apache.tapestry5.http.services.Request;
018import org.apache.tapestry5.internal.services.SessionApplicationStatePersistenceStrategy;
019import org.apache.tapestry5.services.ApplicationStateCreator;
020import org.hibernate.Session;
021
022/**
023 * Persists Hibernate entities as SSOs by storing their primary key in the {@link org.apache.tapestry5.http.services.Session}.
024 *
025 * @see org.apache.tapestry5.hibernate.web.internal.PersistedEntity
026 */
027public class EntityApplicationStatePersistenceStrategy extends SessionApplicationStatePersistenceStrategy
028{
029
030    private final EntityPersistentFieldStrategy delegate;
031
032    public EntityApplicationStatePersistenceStrategy(Request request, Session hibernateSession)
033    {
034        super(request);
035
036        delegate = new EntityPersistentFieldStrategy(hibernateSession, null);
037    }
038
039    @Override
040    protected <T> T transformPersistedValue(Object value)
041    {
042        return value instanceof SessionRestorable ? (T) delegate.convertPersistedToApplicationValue(value) : (T) value;
043    }
044
045    @Override
046    @SuppressWarnings("unchecked")
047    public <T> T get(Class<T> ssoClass, ApplicationStateCreator<T> creator)
048    {
049        final Object persistedValue = getOrCreate(ssoClass, creator);
050
051        if (persistedValue instanceof SessionRestorable)
052        {
053            Object restored = transformPersistedValue(persistedValue);
054
055            // Maybe throw an exception instead?
056            if (restored == null)
057            {
058                set(ssoClass, null);
059                return (T) getOrCreate(ssoClass, creator);
060            }
061
062            return (T) restored;
063        }
064
065        return (T) persistedValue;
066    }
067
068    @Override
069    public <T> void set(Class<T> ssoClass, T sso)
070    {
071        final String key = buildKey(ssoClass);
072
073        if (sso == null)
074        {
075            getSession().setAttribute(key, null);
076            return;
077        }
078
079        Object persistable = delegate.convertApplicationValueToPersisted(sso);
080
081        getSession().setAttribute(key, persistable);
082    }
083
084}