org.hibernate.loader.BatchFetchStyle Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2012, 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.loader;
import org.jboss.logging.Logger;
/**
* Defines the style that should be used to perform batch loading. Which style to use is declared using
* the "{@value org.hibernate.cfg.AvailableSettings#BATCH_FETCH_STYLE}"
* ({@link org.hibernate.cfg.AvailableSettings#BATCH_FETCH_STYLE}) setting
*
* @author Steve Ebersole
*/
public enum BatchFetchStyle {
/**
* The legacy algorithm where we keep a set of pre-built batch sizes based on
* {@link org.hibernate.internal.util.collections.ArrayHelper#getBatchSizes}. Batches are performed
* using the next-smaller pre-built batch size from the number of existing batchable identifiers.
*
* For example, with a batch-size setting of 32 the pre-built batch sizes would be [32, 16, 10, 9, 8, 7, .., 1].
* An attempt to batch load 31 identifiers would result in batches of 16, 10, and 5.
*/
LEGACY,
/**
* Still keeps the concept of pre-built batch sizes, but uses the next-bigger batch size and pads the extra
* identifier placeholders.
*
* Using the same example of a batch-size setting of 32 the pre-built batch sizes would be the same. However, the
* attempt to batch load 31 identifiers would result just a single batch of size 32. The identifiers to load would
* be "padded" (aka, repeated) to make up the difference.
*/
PADDED,
/**
* Dynamically builds its SQL based on the actual number of available ids. Does still limit to the batch-size
* defined on the entity/collection
*/
DYNAMIC;
private static final Logger log = Logger.getLogger( BatchFetchStyle.class );
public static BatchFetchStyle byName(String name) {
return valueOf( name.toUpperCase() );
}
public static BatchFetchStyle interpret(Object setting) {
log.tracef( "Interpreting BatchFetchStyle from setting : %s", setting );
if ( setting == null ) {
return LEGACY; // as default
}
if ( BatchFetchStyle.class.isInstance( setting ) ) {
return (BatchFetchStyle) setting;
}
try {
final BatchFetchStyle byName = byName( setting.toString() );
if ( byName != null ) {
return byName;
}
}
catch (Exception ignore) {
}
log.debugf( "Unable to interpret given setting [%s] as BatchFetchStyle", setting );
return LEGACY; // again as default.
}
}