org.hibernate.id.TableHiLoGenerator Maven / Gradle / Ivy
/*
* 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.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;
/**
* hilo
*
* An IdentifierGenerator that returns a Long, constructed using
* a hi/lo algorithm. The hi value MUST be fetched in a separate transaction
* to the Session transaction so the generator must be able to obtain
* a new connection and commit it. Hence this implementation may not
* be used when the user is supplying connections. In this
* case a SequenceHiLoGenerator would be a better choice (where
* supported).
*
* Mapping parameters supported: table, column, max_lo
*
* @see SequenceHiLoGenerator
* @author Gavin King
*/
public class TableHiLoGenerator extends TableGenerator {
/**
* The max_lo parameter
*/
public static final String MAX_LO = "max_lo";
private OptimizerFactory.LegacyHiLoAlgorithmOptimizer hiloOptimizer;
private int maxLo;
public void configure(Type type, Properties params, Dialect d) {
super.configure(type, params, d);
maxLo = PropertiesHelper.getInt(MAX_LO, params, Short.MAX_VALUE);
if ( maxLo >= 1 ) {
hiloOptimizer = new OptimizerFactory.LegacyHiLoAlgorithmOptimizer( type.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 = generateHolder( session );
}
return value.makeValue();
}
return hiloOptimizer.generate(
new AccessCallback() {
public IntegralDataTypeHolder getNextValue() {
return generateHolder( session );
}
}
);
}
}