Module org.opengis.geoapi

Package org.opengis.filter

Interface NullOperator<R>

Type Parameters:

R - the type of resources (e.g. Feature) to filter.

All Superinterfaces:

ComparisonOperator<R>, Filter<R>, Predicate<R>

@UML(identifier="NullOperator",
     specification=ISO_19143)
public interface NullOperator<R>
extends ComparisonOperator<R>

An operator that tests if an expression's value is null. This corresponds to checking whether the property exists in the real-world. The value 0 is a valid value and is not considered null.

Since:

3.1

Method Summary

Modifier and Type	Method	Description
List<Expression<? super R,?>>	getExpressions()	Returns the expression whose value will be checked for null.
default ComparisonOperatorName	getOperatorType()	Returns the nature of the comparison.

Methods inherited from interface Filter

test

Methods inherited from interface Predicate

and, negate, or

Method Details

getOperatorType

default ComparisonOperatorName getOperatorType()

Returns the nature of the comparison. The default implementation returns PROPERTY_IS_NULL.

Specified by:

getOperatorType in interface ComparisonOperator<R>

Specified by:

getOperatorType in interface Filter<R>

Returns:

the nature of the comparison.

getExpressions

@UML(identifier="expression",
     obligation=MANDATORY,
     specification=ISO_19143)
List<Expression<? super R,?>> getExpressions()

Returns the expression whose value will be checked for null.

Specified by:

getExpressions in interface Filter<R>

Returns:

a list of size 1 containing the expression to test for null value.