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 java.io.Serializable;
018    
019    import javax.persistence.EntityManager;
020    
021    import org.apache.tapestry5.annotations.ImmutableSessionPersistedObject;
022    import org.apache.tapestry5.jpa.EntityManagerManager;
023    
024    /**
025     * Encapsulates a JPA entity name with an entity id.
026     */
027    @ImmutableSessionPersistedObject
028    public class PersistedEntity implements Serializable
029    {
030        private static final long serialVersionUID = 897120520279686518L;
031    
032        private final Class entityClass;
033    
034        private final Object id;
035    
036        private final String persistenceUnitName;
037    
038        public PersistedEntity(final Class entityClass, final Object id,
039                final String persistenceUnitName)
040        {
041            this.entityClass = entityClass;
042            this.id = id;
043            this.persistenceUnitName = persistenceUnitName;
044        }
045    
046        public Object restore(final EntityManagerManager entityManagerManager)
047        {
048            try
049            {
050                final EntityManager entityManager = entityManagerManager
051                        .getEntityManager(persistenceUnitName);
052    
053                return entityManager.find(entityClass, id);
054            }
055            catch (final Exception ex)
056            {
057                throw new RuntimeException(String.format(
058                        "Failed to load session-persisted entity %s(%s): %s", entityClass.getName(),
059                        id, ex));
060            }
061        }
062    
063        @Override
064        public String toString()
065        {
066            return String.format("<PersistedEntity: %s(%s)>", entityClass.getName(), id);
067        }
068    }