/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2005 Open Geospatial Consortium Inc.
*
* All Rights Reserved. http://www.opengis.org/legal/
*/
package org.opengis.filter;
// OpenGIS direct dependencies
import org.opengis.annotation.XmlElement;
import org.opengis.filter.expression.Expression;
/**
* Filter operator that checks if an expression's value is nil.
* <p>
* From the specification:
* <i><pre>
* The PropertyIsNil operator tests the content of the specified property and evaluates if it is nil.
* The operator can also evaluate the nil reason using the nilReason parameter. The implied operator
* for evaluating the nil reason is "equals".
* </pre></i>
* </p>
*
* @author Justin Deoliveira, OpenGeo
* @see http://portal.opengeospatial.org/files/?artifact_id=39968
* @since GeoAPI 2.0
*/
@XmlElement("PropertyIsNil")
public interface PropertyIsNil extends Filter {
/** Operator name used to check FilterCapabilities */
public static String NAME = "Nil";
/**
* Returns the expression whose value will be checked for {@code null}.
*/
@XmlElement("expression")
Expression getExpression();
/**
* The nil reason.
*/
@XmlElement("nilReason")
Object getNilReason();
}