/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.query.criteria.internal.expression;
import java.io.Serializable;
import javax.persistence.criteria.Expression;
import org.hibernate.query.criteria.internal.CriteriaBuilderImpl;
import org.hibernate.query.criteria.internal.ParameterRegistry;
import org.hibernate.query.criteria.internal.Renderable;
import org.hibernate.query.criteria.internal.compile.RenderingContext;
/**
* Models an ANSI SQL <tt>NULLIF</tt> expression. <tt>NULLIF</tt> is a specialized <tt>CASE</tt> statement.
*
* @author Steve Ebersole
*/
public class NullifExpression<T> extends ExpressionImpl<T> implements Serializable {
private final Expression<? extends T> primaryExpression;
private final Expression<?> secondaryExpression;
public NullifExpression(
CriteriaBuilderImpl criteriaBuilder,
Class<T> javaType,
Expression<? extends T> primaryExpression,
Expression<?> secondaryExpression) {
super( criteriaBuilder, (Class<T>)determineType(javaType, primaryExpression) );
this.primaryExpression = primaryExpression;
this.secondaryExpression = secondaryExpression;
}
public NullifExpression(
CriteriaBuilderImpl criteriaBuilder,
Class<T> javaType,
Expression<? extends T> primaryExpression,
Object secondaryExpression) {
super( criteriaBuilder, (Class<T>)determineType(javaType, primaryExpression) );
this.primaryExpression = primaryExpression;
this.secondaryExpression = new LiteralExpression( criteriaBuilder, secondaryExpression );
}
private static Class determineType(Class javaType, Expression primaryExpression) {
return javaType != null ? javaType : primaryExpression.getJavaType();
}
public Expression<? extends T> getPrimaryExpression() {
return primaryExpression;
}
public Expression<?> getSecondaryExpression() {
return secondaryExpression;
}
public void registerParameters(ParameterRegistry registry) {
Helper.possibleParameter( getPrimaryExpression(), registry );
Helper.possibleParameter( getSecondaryExpression(), registry );
}
public String render(RenderingContext renderingContext) {
return "nullif("
+ ( (Renderable) getPrimaryExpression() ).render( renderingContext )
+ ','
+ ( (Renderable) getSecondaryExpression() ).render( renderingContext )
+ ")";
}
public String renderProjection(RenderingContext renderingContext) {
return render( renderingContext );
}
}