org.hibernate.query.criteria.internal.expression.NullifExpression Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of hibernate-core Show documentation

Hibernate's core ORM functionality

There is a newer version: 7.0.0.Alpha1

/*
 * 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 .
 */
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 NULLIF expression.  NULLIF is a specialized CASE statement.
 *
 * @author Steve Ebersole
 */
public class NullifExpression extends ExpressionImpl implements Serializable {
	private final Expression primaryExpression;
	private final Expression secondaryExpression;

	public NullifExpression(
			CriteriaBuilderImpl criteriaBuilder,
			Class javaType,
			Expression primaryExpression,
			Expression secondaryExpression) {
		super( criteriaBuilder, (Class)determineType(javaType, primaryExpression) );
		this.primaryExpression = primaryExpression;
		this.secondaryExpression = secondaryExpression;
	}

	public NullifExpression(
			CriteriaBuilderImpl criteriaBuilder,
			Class javaType,
			Expression primaryExpression,
			Object secondaryExpression) {
		super( criteriaBuilder, (Class)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 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 )
				+ ")";
	}
}