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Hibernate's entity version (audit/history) support
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or .
*/
package org.hibernate.envers.event.spi;
import java.io.Serializable;
import java.util.Set;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.envers.boot.internal.EnversService;
import org.hibernate.envers.exception.AuditException;
import org.hibernate.envers.internal.entities.RelationDescription;
import org.hibernate.envers.internal.entities.RelationType;
import org.hibernate.envers.internal.entities.mapper.id.IdMapper;
import org.hibernate.envers.internal.synchronization.AuditProcess;
import org.hibernate.envers.internal.synchronization.work.CollectionChangeWorkUnit;
import org.hibernate.envers.internal.tools.EntityTools;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.proxy.HibernateProxy;
/**
* Base class for all Envers event listeners
*
* @author Adam Warski (adam at warski dot org)
* @author HernпїЅn Chanfreau
* @author Steve Ebersole
* @author Michal Skowronek (mskowr at o2 dot pl)
*/
public abstract class BaseEnversEventListener implements EnversListener {
private final EnversService enversService;
protected BaseEnversEventListener(EnversService enversService) {
this.enversService = enversService;
}
protected EnversService getEnversService() {
return enversService;
}
protected final void generateBidirectionalCollectionChangeWorkUnits(
AuditProcess auditProcess,
EntityPersister entityPersister,
String entityName,
Object[] newState,
Object[] oldState,
SessionImplementor session) {
// Checking if this is enabled in configuration ...
if ( !enversService.getGlobalConfiguration().isGenerateRevisionsForCollections() ) {
return;
}
// Checks every property of the entity, if it is an "owned" to-one relation to another entity.
// If the value of that property changed, and the relation is bi-directional, a new revision
// for the related entity is generated.
final String[] propertyNames = entityPersister.getPropertyNames();
for ( int i = 0; i < propertyNames.length; i++ ) {
final String propertyName = propertyNames[i];
final RelationDescription relDesc = enversService.getEntitiesConfigurations().getRelationDescription(
entityName,
propertyName
);
if ( relDesc != null && relDesc.isBidirectional() && relDesc.getRelationType() == RelationType.TO_ONE &&
relDesc.isInsertable() ) {
// Checking for changes
final Object oldValue = oldState == null ? null : oldState[i];
final Object newValue = newState == null ? null : newState[i];
if ( !EntityTools.entitiesEqual( session, relDesc.getToEntityName(), oldValue, newValue ) ) {
// We have to generate changes both in the old collection (size decreses) and new collection
// (size increases).
if ( newValue != null ) {
addCollectionChangeWorkUnit( auditProcess, session, entityName, relDesc, newValue );
}
if ( oldValue != null ) {
addCollectionChangeWorkUnit( auditProcess, session, entityName, relDesc, oldValue );
}
}
}
}
}
private void addCollectionChangeWorkUnit(
AuditProcess auditProcess, SessionImplementor session,
String fromEntityName, RelationDescription relDesc, Object value) {
// relDesc.getToEntityName() doesn't always return the entity name of the value - in case
// of subclasses, this will be root class, no the actual class. So it can't be used here.
String toEntityName;
Serializable id;
if ( value instanceof HibernateProxy ) {
final HibernateProxy hibernateProxy = (HibernateProxy) value;
id = hibernateProxy.getHibernateLazyInitializer().getIdentifier();
// We've got to initialize the object from the proxy to later read its state.
value = EntityTools.getTargetFromProxy( session.getFactory(), hibernateProxy );
// HHH-7249
// This call must occur after the proxy has been initialized or the returned name will
// be to the base class which will impact the discriminator value chosen when using an
// inheritance strategy with discriminators.
toEntityName = session.bestGuessEntityName( value );
}
else {
toEntityName = session.guessEntityName( value );
final IdMapper idMapper = enversService.getEntitiesConfigurations().get( toEntityName ).getIdMapper();
id = (Serializable) idMapper.mapToIdFromEntity( value );
}
final Set toPropertyNames = enversService.getEntitiesConfigurations().getToPropertyNames(
fromEntityName,
relDesc.getFromPropertyName(),
toEntityName
);
final String toPropertyName = toPropertyNames.iterator().next();
auditProcess.addWorkUnit(
new CollectionChangeWorkUnit(
session,
toEntityName,
toPropertyName,
enversService,
id,
value
)
);
}
protected void checkIfTransactionInProgress(SessionImplementor session) {
if ( !session.isTransactionInProgress() ) {
// Historical data would not be flushed to audit tables if outside of active transaction
// (AuditProcess#doBeforeTransactionCompletion(SessionImplementor) not executed).
throw new AuditException( "Unable to create revision because of non-active transaction" );
}
}
}