package org.hibernate.id;
import java.io.Serializable;
import java.util.Properties;
import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.Session;
import org.hibernate.TransientObjectException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.ForeignKeys;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.type.EntityType;
import org.hibernate.type.Type;
/**
* <b>foreign</b><br>
* <br>
* An <tt>Identifier</tt> generator that uses the value of the id property of an
* associated object<br>
* <br>
* One mapping parameter is required: property.
*
* @author Gavin King
*/
public class ForeignGenerator implements IdentifierGenerator, Configurable {
private String propertyName;
private String entityName;
/**
* @see org.hibernate.id.IdentifierGenerator#generate(org.hibernate.engine.SessionImplementor, java.lang.Object)
*/
public Serializable generate(SessionImplementor sessionImplementor, Object object)
throws HibernateException {
Session session = (Session) sessionImplementor;
Object associatedObject = sessionImplementor.getFactory()
.getClassMetadata( entityName )
.getPropertyValue( object, propertyName, session.getEntityMode() );
if ( associatedObject == null ) {
throw new IdentifierGenerationException(
"attempted to assign id from null one-to-one property: " +
propertyName
);
}
EntityType type = (EntityType) sessionImplementor.getFactory()
.getClassMetadata( entityName )
.getPropertyType( propertyName );
Serializable id;
try {
id = ForeignKeys.getEntityIdentifierIfNotUnsaved(
type.getAssociatedEntityName(),
associatedObject,
sessionImplementor
);
}
catch (TransientObjectException toe) {
id = session.save( type.getAssociatedEntityName(), associatedObject );
}
if ( session.contains(object) ) {
//abort the save (the object is already saved by a circular cascade)
return IdentifierGeneratorFactory.SHORT_CIRCUIT_INDICATOR;
//throw new IdentifierGenerationException("save associated object first, or disable cascade for inverse association");
}
return id;
}
/**
* @see org.hibernate.id.Configurable#configure(org.hibernate.type.Type, java.util.Properties, org.hibernate.dialect.Dialect)
*/
public void configure(Type type, Properties params, Dialect d)
throws MappingException {
propertyName = params.getProperty("property");
entityName = params.getProperty(ENTITY_NAME);
if (propertyName==null) throw new MappingException(
"param named \"property\" is required for foreign id generation strategy"
);
}
}
|