oracle.toplink.essentials.internal.parsing.NullComparisonNode Maven / Gradle / Ivy
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
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*/
// Copyright (c) 1998, 2007, Oracle. All rights reserved.
package oracle.toplink.essentials.internal.parsing;
import oracle.toplink.essentials.expressions.*;
/**
* INTERNAL
* Purpose: This node represents the IS NULL comparisons
*
Responsibilities:
* - Generate the correct expression for IS NULL
*
* @author Jon Driscoll and Joel Lucuik
* @since TopLink 4.0
*/
public class NullComparisonNode extends SimpleConditionalExpressionNode {
/**
* Return a new NullComparisonNode.
*/
public NullComparisonNode() {
super();
}
/**
* INTERNAL
* Validate node and calculate its type.
*/
public void validate(ParseTreeContext context) {
TypeHelper typeHelper = context.getTypeHelper();
if (left != null) {
left.validate(context);
left.validateParameter(context, typeHelper.getObjectType());
}
setType(typeHelper.getBooleanType());
}
/**
* INTERNAL
* Return a TopLink expression for this node.
*/
public Expression generateExpression(GenerationContext context) {
Expression whereClause = getLeft().generateExpression(context);
whereClause = whereClause.isNull();
return whereClause;
}
}