org.hibernate.engine.VersionValue Maven / Gradle / Ivy
/*
* 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.engine;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.hibernate.MappingException;
import org.hibernate.id.IdentifierGeneratorHelper;
/**
* A strategy for determining if a version value is an version of
* a new transient instance or a previously persistent transient instance.
* The strategy is determined by the unsaved-value attribute in
* the mapping file.
*
* @author Gavin King
*/
public class VersionValue {
private static final Logger log = LoggerFactory.getLogger(VersionValue.class);
private final Object value;
/**
* Assume the transient instance is newly instantiated if the version
* is null, otherwise assume it is a detached instance.
*/
public static final VersionValue NULL = new VersionValue() {
public final Boolean isUnsaved(Object version) {
log.trace("version unsaved-value strategy NULL");
return version==null ? Boolean.TRUE : Boolean.FALSE;
}
public Object getDefaultValue(Object currentValue) {
return null;
}
public String toString() {
return "VERSION_SAVE_NULL";
}
};
/**
* Assume the transient instance is newly instantiated if the version
* is null, otherwise defer to the identifier unsaved-value.
*/
public static final VersionValue UNDEFINED = new VersionValue() {
public final Boolean isUnsaved(Object version) {
log.trace("version unsaved-value strategy UNDEFINED");
return version==null ? Boolean.TRUE : null;
}
public Object getDefaultValue(Object currentValue) {
return currentValue;
}
public String toString() {
return "VERSION_UNDEFINED";
}
};
/**
* Assume the transient instance is newly instantiated if the version
* is negative, otherwise assume it is a detached instance.
*/
public static final VersionValue NEGATIVE = new VersionValue() {
public final Boolean isUnsaved(Object version) throws MappingException {
log.trace("version unsaved-value strategy NEGATIVE");
if (version==null) return Boolean.TRUE;
if (version instanceof Number) {
return ( (Number) version ).longValue() < 0l ? Boolean.TRUE : Boolean.FALSE;
}
else {
throw new MappingException("unsaved-value NEGATIVE may only be used with short, int and long types");
}
}
public Object getDefaultValue(Object currentValue) {
return IdentifierGeneratorHelper.getIntegralDataTypeHolder( currentValue.getClass() )
.initialize( -1L )
.makeValue();
}
public String toString() {
return "VERSION_NEGATIVE";
}
};
protected VersionValue() {
this.value = null;
}
/**
* Assume the transient instance is newly instantiated if
* its version is null or equal to value
* @param value value to compare to
*/
public VersionValue(Object value) {
this.value = value;
}
/**
* Does the given version belong to a new instance?
*
* @param version version to check
* @return true is unsaved, false is saved, null is undefined
*/
public Boolean isUnsaved(Object version) throws MappingException {
if ( log.isTraceEnabled() ) log.trace("version unsaved-value: " + value);
return version==null || version.equals(value) ? Boolean.TRUE : Boolean.FALSE;
}
public Object getDefaultValue(Object currentValue) {
return value;
}
public String toString() {
return "version unsaved-value: " + value;
}
}