org.hibernate.id.enhanced.SequenceStyleGenerator Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of hibernate-core Show documentation
Show all versions of hibernate-core Show documentation
The core functionality of Hibernate
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
*
* 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.enhanced;
import java.util.Properties;
import java.io.Serializable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.id.PersistentIdentifierGenerator;
import org.hibernate.id.Configurable;
import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.mapping.Table;
import org.hibernate.util.PropertiesHelper;
import org.hibernate.type.Type;
import org.hibernate.dialect.Dialect;
/**
* Generates identifier values based on an sequence-style database structure.
* Variations range from actually using a sequence to using a table to mimic
* a sequence. These variations are encapsulated by the {@link DatabaseStructure}
* interface internally.
*
* General configuration parameters:
*
*
* NAME
* DEFAULT
* DESCRIPTION
*
*
* {@link #SEQUENCE_PARAM}
* {@link #DEF_SEQUENCE_NAME}
* The name of the sequence/table to use to store/retrieve values
*
*
* {@link #INITIAL_PARAM}
* {@link #DEFAULT_INITIAL_VALUE}
* The initial value to be stored for the given segment; the effect in terms of storage varies based on {@link Optimizer} and {@link DatabaseStructure}
*
*
* {@link #INCREMENT_PARAM}
* {@link #DEFAULT_INCREMENT_SIZE}
* The increment size for the underlying segment; the effect in terms of storage varies based on {@link Optimizer} and {@link DatabaseStructure}
*
*
* {@link #OPT_PARAM}
* depends on defined increment size
* Allows explicit definition of which optimization strategy to use
*
* {@link #FORCE_TBL_PARAM}
* false
* Allows explicit definition of which optimization strategy to use
*
*
*
* Configuration parameters used specifically when the underlying structure is a table:
*
*
* NAME
* DEFAULT
* DESCRIPTION
*
*
* {@link #VALUE_COLUMN_PARAM}
* {@link #DEF_VALUE_COLUMN}
* The name of column which holds the sequence value for the given segment
*
*
*
* @author Steve Ebersole
*/
public class SequenceStyleGenerator implements PersistentIdentifierGenerator, Configurable {
private static final Logger log = LoggerFactory.getLogger( SequenceStyleGenerator.class );
// general purpose parameters ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
public static final String SEQUENCE_PARAM = "sequence_name";
public static final String DEF_SEQUENCE_NAME = "hibernate_sequence";
public static final String INITIAL_PARAM = "initial_value";
public static final int DEFAULT_INITIAL_VALUE = 1;
public static final String INCREMENT_PARAM = "increment_size";
public static final int DEFAULT_INCREMENT_SIZE = 1;
public static final String OPT_PARAM = "optimizer";
public static final String FORCE_TBL_PARAM = "force_table_use";
// table-specific parameters ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
public static final String VALUE_COLUMN_PARAM = "value_column";
public static final String DEF_VALUE_COLUMN = "next_val";
// state ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
private DatabaseStructure databaseStructure;
private Optimizer optimizer;
private Type identifierType;
public DatabaseStructure getDatabaseStructure() {
return databaseStructure;
}
public Optimizer getOptimizer() {
return optimizer;
}
public Type getIdentifierType() {
return identifierType;
}
// Configurable implementation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
public void configure(Type type, Properties params, Dialect dialect) throws MappingException {
identifierType = type;
boolean forceTableUse = PropertiesHelper.getBoolean( FORCE_TBL_PARAM, params, false );
String sequenceName = PropertiesHelper.getString( SEQUENCE_PARAM, params, DEF_SEQUENCE_NAME );
if ( sequenceName.indexOf( '.' ) < 0 ) {
String schemaName = params.getProperty( SCHEMA );
String catalogName = params.getProperty( CATALOG );
sequenceName = Table.qualify( catalogName, schemaName, sequenceName );
}
int initialValue = PropertiesHelper.getInt( INITIAL_PARAM, params, DEFAULT_INITIAL_VALUE );
int incrementSize = PropertiesHelper.getInt( INCREMENT_PARAM, params, DEFAULT_INCREMENT_SIZE );
String valueColumnName = PropertiesHelper.getString( VALUE_COLUMN_PARAM, params, DEF_VALUE_COLUMN );
String defOptStrategy = incrementSize <= 1 ? OptimizerFactory.NONE : OptimizerFactory.POOL;
String optimizationStrategy = PropertiesHelper.getString( OPT_PARAM, params, defOptStrategy );
if ( OptimizerFactory.NONE.equals( optimizationStrategy ) && incrementSize > 1 ) {
log.warn( "config specified explicit optimizer of [" + OptimizerFactory.NONE + "], but [" + INCREMENT_PARAM + "=" + incrementSize + "; honoring optimizer setting" );
incrementSize = 1;
}
if ( dialect.supportsSequences() && !forceTableUse ) {
if ( OptimizerFactory.POOL.equals( optimizationStrategy ) && !dialect.supportsPooledSequences() ) {
// TODO : may even be better to fall back to a pooled table strategy here so that the db stored values remain consistent...
optimizationStrategy = OptimizerFactory.HILO;
}
databaseStructure = new SequenceStructure( dialect, sequenceName, initialValue, incrementSize );
}
else {
databaseStructure = new TableStructure( dialect, sequenceName, valueColumnName, initialValue, incrementSize );
}
optimizer = OptimizerFactory.buildOptimizer( optimizationStrategy, identifierType.getReturnedClass(), incrementSize );
databaseStructure.prepare( optimizer );
}
// IdentifierGenerator implementation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
public Serializable generate(SessionImplementor session, Object object) throws HibernateException {
return optimizer.generate( databaseStructure.buildCallback( session ) );
}
// PersistentIdentifierGenerator implementation ~~~~~~~~~~~~~~~~~~~~~~~~~~~
public Object generatorKey() {
return databaseStructure.getName();
}
public String[] sqlCreateStrings(Dialect dialect) throws HibernateException {
return databaseStructure.sqlCreateStrings( dialect );
}
public String[] sqlDropStrings(Dialect dialect) throws HibernateException {
return databaseStructure.sqlDropStrings( dialect );
}
}