/*******************************************************************************
* Copyright (c) 1998, 2011 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* tware - initial implementation as part of JPA 2.0 RI
******************************************************************************/
package org.eclipse.persistence.internal.jpa.parsing;
import org.eclipse.persistence.expressions.Expression;
import org.eclipse.persistence.queries.ObjectLevelReadQuery;
import org.eclipse.persistence.queries.ReportQuery;
/**
* INTERNAL
* <p><b>Purpose</b>: Represent an NULLIF in EJBQL
* <p><b>Responsibilities</b>:<ul>
* <li> Generate the correct expression for an NULLIF in EJBQL
* </ul>
* @author tware
* @since EclipseLink 1.2
*/
public class NullIfNode extends Node {
public NullIfNode(){
super();
}
/**
* INTERNAL
* Apply this node to the passed query
*/
public void applyToQuery(ObjectLevelReadQuery theQuery, GenerationContext generationContext) {
if (theQuery instanceof ReportQuery) {
ReportQuery reportQuery = (ReportQuery)theQuery;
Expression expression = generateExpression(generationContext);
reportQuery.addItem("NullIf(" + getLeft().getAsString() + "," + getRight().getAsString() + ")", expression);
}
}
/**
* INTERNAL
* Generate the a new EclipseLink NullIf expression for this node.
*/
public Expression generateExpression(GenerationContext context) {
Expression whereClause = getLeft().generateExpression(context).nullIf(getRight().generateExpression(context));
return whereClause;
}
public void validate(ParseTreeContext context) {
left.validate(context);
right.validate(context);
setType(left.getType());
}
}