org.hibernate.criterion.NullExpression 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
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*
*/
package org.hibernate.criterion;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.engine.spi.TypedValue;
import org.hibernate.internal.util.StringHelper;
/**
* Constrains a property to be null
*
* @author Gavin King
*/
public class NullExpression implements Criterion {
private static final TypedValue[] NO_VALUES = new TypedValue[0];
private final String propertyName;
/**
* Constructs a NullExpression
*
* @param propertyName The name of the property to check for null
*
* @see Restrictions#isNull
*/
protected NullExpression(String propertyName) {
this.propertyName = propertyName;
}
@Override
public String toSqlString(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
final String[] columns = criteriaQuery.findColumns( propertyName, criteria );
String result = StringHelper.join(
" and ",
StringHelper.suffix( columns, " is null" )
);
if ( columns.length > 1 ) {
result = '(' + result + ')';
}
return result;
}
@Override
public TypedValue[] getTypedValues(Criteria criteria, CriteriaQuery criteriaQuery) throws HibernateException {
return NO_VALUES;
}
@Override
public String toString() {
return propertyName + " is null";
}
}