/*
* 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
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*/
package org.hibernate.id;
import java.io.Serializable;
import java.util.Properties;
import java.util.UUID;
import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.spi.SessionImplementor;
import org.hibernate.id.uuid.StandardRandomStrategy;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.internal.util.ReflectHelper;
import org.hibernate.type.Type;
import org.hibernate.type.descriptor.java.UUIDTypeDescriptor;
import org.jboss.logging.Logger;
An IdentifierGenerator
which generates UUID
values using a pluggable generation strategy
. The values this generator can return include UUID
, String
and byte[16]
Supports 2 config parameters:
UUID_GEN_STRATEGY
- names the UUIDGenerationStrategy
instance to use
UUID_GEN_STRATEGY_CLASS
- names the UUIDGenerationStrategy
class to use
Currently there are 2 standard implementations of UUIDGenerationStrategy
:
StandardRandomStrategy
(the default, if none specified)
CustomVersionOneStrategy
Author: Steve Ebersole
/**
* An {@link IdentifierGenerator} which generates {@link UUID} values using a pluggable
* {@link UUIDGenerationStrategy generation strategy}. The values this generator can return
* include {@link UUID}, {@link String} and byte[16]
* <p/>
* Supports 2 config parameters:<ul>
* <li>{@link #UUID_GEN_STRATEGY} - names the {@link UUIDGenerationStrategy} instance to use</li>
* <li>{@link #UUID_GEN_STRATEGY_CLASS} - names the {@link UUIDGenerationStrategy} class to use</li>
* </ul>
* <p/>
* Currently there are 2 standard implementations of {@link UUIDGenerationStrategy}:<ul>
* <li>{@link StandardRandomStrategy} (the default, if none specified)</li>
* <li>{@link org.hibernate.id.uuid.CustomVersionOneStrategy}</li>
* </ul>
*
* @author Steve Ebersole
*/
public class UUIDGenerator implements IdentifierGenerator, Configurable {
public static final String UUID_GEN_STRATEGY = "uuid_gen_strategy";
public static final String UUID_GEN_STRATEGY_CLASS = "uuid_gen_strategy_class";
private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, UUIDGenerator.class.getName());
private UUIDGenerationStrategy strategy;
private UUIDTypeDescriptor.ValueTransformer valueTransformer;
public static UUIDGenerator buildSessionFactoryUniqueIdentifierGenerator() {
final UUIDGenerator generator = new UUIDGenerator();
generator.strategy = StandardRandomStrategy.INSTANCE;
generator.valueTransformer = UUIDTypeDescriptor.ToStringTransformer.INSTANCE;
return generator;
}
public void configure(Type type, Properties params, Dialect d) throws MappingException {
// check first for the strategy instance
strategy = (UUIDGenerationStrategy) params.get( UUID_GEN_STRATEGY );
if ( strategy == null ) {
// next check for the strategy class
final String strategyClassName = params.getProperty( UUID_GEN_STRATEGY_CLASS );
if ( strategyClassName != null ) {
try {
final Class strategyClass = ReflectHelper.classForName( strategyClassName );
try {
strategy = (UUIDGenerationStrategy) strategyClass.newInstance();
}
catch ( Exception ignore ) {
LOG.unableToInstantiateUuidGenerationStrategy(ignore);
}
}
catch ( ClassNotFoundException ignore ) {
LOG.unableToLocateUuidGenerationStrategy(strategyClassName);
}
}
}
if ( strategy == null ) {
// lastly use the standard random generator
strategy = StandardRandomStrategy.INSTANCE;
}
if ( UUID.class.isAssignableFrom( type.getReturnedClass() ) ) {
valueTransformer = UUIDTypeDescriptor.PassThroughTransformer.INSTANCE;
}
else if ( String.class.isAssignableFrom( type.getReturnedClass() ) ) {
valueTransformer = UUIDTypeDescriptor.ToStringTransformer.INSTANCE;
}
else if ( byte[].class.isAssignableFrom( type.getReturnedClass() ) ) {
valueTransformer = UUIDTypeDescriptor.ToBytesTransformer.INSTANCE;
}
else {
throw new HibernateException( "Unanticipated return type [" + type.getReturnedClass().getName() + "] for UUID conversion" );
}
}
public Serializable generate(SessionImplementor session, Object object) throws HibernateException {
return valueTransformer.transform( strategy.generateUUID( session ) );
}
}