Hibernate example source code file (ExplicitTruthValueCheck.java)

This example Hibernate source code file (ExplicitTruthValueCheck.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

abstractsimplepredicate, explicittruthvaluecheck, explicittruthvaluecheck, expression, expression, io, renderable, serializable, string, string, truthvalue, truthvalue

The Hibernate ExplicitTruthValueCheck.java source code

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2009 by Red Hat Inc and/or its affiliates or by
 * third-party contributors as indicated by either @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.ejb.criteria.predicate;
import java.io.Serializable;
import javax.persistence.criteria.Expression;
import org.hibernate.ejb.criteria.CriteriaBuilderImpl;
import org.hibernate.ejb.criteria.CriteriaQueryCompiler;
import org.hibernate.ejb.criteria.ParameterRegistry;
import org.hibernate.ejb.criteria.Renderable;

/**
 * ANSI-SQL defines <tt>TRUE, FALSE and UNKNOWN as truth values.  These
 * <i>truth values are used to explicitly check the result of a boolean expression (the syntax is like
 * <tt>a > b IS TRUE.  IS TRUE is the assumed default.
 * <p/>
 * JPA defines support for only <tt>IS TRUE and IS FALSE, not IS UNKNOWN (a > NULL
 * is an example where the result would be UNKNOWN.
 *
 * @author Steve Ebersole
 */
public class ExplicitTruthValueCheck
		extends AbstractSimplePredicate
		implements Serializable {
	// TODO : given that JPA supports only TRUE and FALSE, can this be handled just with negation?
	private final Expression<Boolean> booleanExpression;
	private final TruthValue truthValue;

	public ExplicitTruthValueCheck(CriteriaBuilderImpl criteriaBuilder, Expression<Boolean> booleanExpression, TruthValue truthValue) {
		super( criteriaBuilder );
		this.booleanExpression = booleanExpression;
		this.truthValue = truthValue;
	}

	public Expression<Boolean> getBooleanExpression() {
		return booleanExpression;
	}

	public TruthValue getTruthValue() {
		return truthValue;
	}

	public void registerParameters(ParameterRegistry registry) {
		Helper.possibleParameter( getBooleanExpression(), registry );
	}

	public String render(CriteriaQueryCompiler.RenderingContext renderingContext) {
		return ( (Renderable) getBooleanExpression() ).render( renderingContext )
				+ " = "
				+ ( getTruthValue() == TruthValue.TRUE ? "true" : "false" );
	}

	public String renderProjection(CriteriaQueryCompiler.RenderingContext renderingContext) {
		return render( renderingContext );
	}
}