org.geotools.filter
Interface NullFilter

All Superinterfaces:
Filter, FilterType
All Known Implementing Classes:
NullFilterImpl

public interface NullFilter
extends Filter

Defines a null filter, which checks to see if an attribute is null.

Version:
$Id: NullFilter.java,v 1.3 2003/08/07 21:30:36 cholmesny Exp $
Author:
Rob Hranac, Vision for New York, Chris Holmes, TOPP

Field Summary
 
Fields inherited from interface org.geotools.filter.Filter
ALL, NONE
 
Fields inherited from interface org.geotools.filter.FilterType
BETWEEN, COMPARE_EQUALS, COMPARE_GREATER_THAN, COMPARE_GREATER_THAN_EQUAL, COMPARE_LESS_THAN, COMPARE_LESS_THAN_EQUAL, COMPARE_NOT_EQUALS, FID, GEOMETRY_BBOX, GEOMETRY_BEYOND, GEOMETRY_CONTAINS, GEOMETRY_CROSSES, GEOMETRY_DISJOINT, GEOMETRY_DWITHIN, GEOMETRY_EQUALS, GEOMETRY_INTERSECTS, GEOMETRY_OVERLAPS, GEOMETRY_TOUCHES, GEOMETRY_WITHIN, LIKE, LOGIC_AND, LOGIC_NOT, LOGIC_OR, NULL
 
Method Summary
 boolean contains(Feature feature)
          Determines whether or not a given feature is null for the nullCheck attribute.
 Expression getNullCheckValue()
          Returns the expression being checked for null.
 void nullCheckValue(Expression nullCheck)
          Determines whether or not a given feature is 'inside' this filter.
 
Methods inherited from interface org.geotools.filter.Filter
accept, and, getFilterType, not, or
 

Method Detail

nullCheckValue

public void nullCheckValue(Expression nullCheck)
                    throws IllegalFilterException
Determines whether or not a given feature is 'inside' this filter.

Parameters:
nullCheck - The attribute expression to null check.
Throws:
IllegalFilterException - If attempting to add a non-attribute expression.
Task:
REVISIT: change arg to AttributeExpression?, REVISIT: change name to setNullCheckValue.

getNullCheckValue

public Expression getNullCheckValue()
Returns the expression being checked for null.

Returns:
the Expression to null check.

contains

public boolean contains(Feature feature)
Determines whether or not a given feature is null for the nullCheck attribute.

Specified by:
contains in interface Filter
Parameters:
feature - Specified feature to examine.
Returns:
Flag confirming whether or not this feature is inside the filter.


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