/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Middleware LLC.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.envers.entities;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.hibernate.envers.configuration.AuditConfiguration;
import org.hibernate.envers.entities.mapper.id.IdMapper;
import org.hibernate.envers.exception.AuditException;
import org.hibernate.envers.reader.AuditReaderImplementor;
import org.hibernate.envers.tools.reflection.ReflectionTools;
import org.hibernate.util.ReflectHelper;
/**
* @author Adam Warski (adam at warski dot org)
*/
public class EntityInstantiator {
private final AuditConfiguration verCfg;
private final AuditReaderImplementor versionsReader;
public EntityInstantiator(AuditConfiguration verCfg, AuditReaderImplementor versionsReader) {
this.verCfg = verCfg;
this.versionsReader = versionsReader;
}
/**
* Creates an entity instance based on an entry from the versions table.
* @param entityName Name of the entity, which instances should be read
* @param versionsEntity An entry in the versions table, from which data should be mapped.
* @param revision Revision at which this entity was read.
* @return An entity instance, with versioned properties set as in the versionsEntity map, and proxies
* created for collections.
*/
public Object createInstanceFromVersionsEntity(String entityName, Map versionsEntity, Number revision) {
if (versionsEntity == null) {
return null;
}
// The $type$ property holds the name of the (versions) entity
String type = verCfg.getEntCfg().getEntityNameForVersionsEntityName((String) versionsEntity.get("$type$"));
if (type != null) {
entityName = type;
}
// First mapping the primary key
IdMapper idMapper = verCfg.getEntCfg().get(entityName).getIdMapper();
Map originalId = (Map) versionsEntity.get(verCfg.getAuditEntCfg().getOriginalIdPropName());
Object primaryKey = idMapper.mapToIdFromMap(originalId);
// Checking if the entity is in cache
if (versionsReader.getFirstLevelCache().contains(entityName, revision, primaryKey)) {
return versionsReader.getFirstLevelCache().get(entityName, revision, primaryKey);
}
// If it is not in the cache, creating a new entity instance
Object ret;
try {
Class<?> cls = ReflectionTools.loadClass(entityName);
ret = ReflectHelper.getDefaultConstructor(cls).newInstance();
} catch (Exception e) {
throw new AuditException(e);
}
// Putting the newly created entity instance into the first level cache, in case a one-to-one bidirectional
// relation is present (which is eagerly loaded).
versionsReader.getFirstLevelCache().put(entityName, revision, primaryKey, ret);
verCfg.getEntCfg().get(entityName).getPropertyMapper().mapToEntityFromMap(verCfg, ret, versionsEntity, primaryKey,
versionsReader, revision);
idMapper.mapToEntityFromMap(ret, originalId);
return ret;
}
@SuppressWarnings({"unchecked"})
public void addInstancesFromVersionsEntities(String entityName, Collection addTo, List<Map> versionsEntities, Number revision) {
for (Map versionsEntity : versionsEntities) {
addTo.add(createInstanceFromVersionsEntity(entityName, versionsEntity, revision));
}
}
}