/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2010, Red Hat Inc. 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 Inc.
*
* 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.id;
import java.io.Serializable;
import java.util.Properties;
import org.hibernate.MappingException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.enhanced.AccessCallback;
import org.hibernate.id.enhanced.OptimizerFactory;
import org.hibernate.type.Type;
import org.hibernate.util.PropertiesHelper;
/**
* <b>seqhilo</b><br>
* <br>
* An <tt>IdentifierGenerator</tt> that combines a hi/lo algorithm with an underlying
* oracle-style sequence that generates hi values. The user may specify a
* maximum lo value to determine how often new hi values are fetched.<br>
* <br>
* If sequences are not available, <tt>TableHiLoGenerator</tt> might be an
* alternative.<br>
* <br>
* Mapping parameters supported: sequence, max_lo, parameters.
*
* @see TableHiLoGenerator
* @author Gavin King
*/
public class SequenceHiLoGenerator extends SequenceGenerator {
public static final String MAX_LO = "max_lo";
private int maxLo;
private OptimizerFactory.LegacyHiLoAlgorithmOptimizer hiloOptimizer;
public void configure(Type type, Properties params, Dialect d) throws MappingException {
super.configure(type, params, d);
maxLo = PropertiesHelper.getInt( MAX_LO, params, 9 );
if ( maxLo >= 1 ) {
hiloOptimizer = new OptimizerFactory.LegacyHiLoAlgorithmOptimizer(
getIdentifierType().getReturnedClass(),
maxLo
);
}
}
public synchronized Serializable generate(final SessionImplementor session, Object obj) {
// maxLo < 1 indicates a hilo generator with no hilo :?
if ( maxLo < 1 ) {
//keep the behavior consistent even for boundary usages
IntegralDataTypeHolder value = null;
while ( value == null || value.lt( 0 ) ) {
value = super.generateHolder( session );
}
return value.makeValue();
}
return hiloOptimizer.generate(
new AccessCallback() {
public IntegralDataTypeHolder getNextValue() {
return generateHolder( session );
}
}
);
}
/**
* For testing/assertion purposes
*
* @return The optimizer
*/
OptimizerFactory.LegacyHiLoAlgorithmOptimizer getHiloOptimizer() {
return hiloOptimizer;
}
}