Package org.geotools.filter

Class NullFilterImpl

Object

FilterAbstract

AbstractFilter

NullFilterImpl

All Implemented Interfaces:

Filter, PropertyIsNull, FilterType

public class NullFilterImpl
extends AbstractFilter
implements PropertyIsNull

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

Author:

Rob Hranac, Vision for New York

Field Summary

Fields inherited from class AbstractFilter

LOGGER

Fields inherited from interface Filter

EXCLUDE, INCLUDE

Fields inherited from interface FilterType

ALL, 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, NONE, NULL

Fields inherited from interface PropertyIsNull

NAME

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	NullFilterImpl(Expression expresion)

Method Summary

Modifier and Type	Method	Description
Object	accept(FilterVisitor visitor, Object extraData)	Used by FilterVisitors to perform some action on this filter instance.
boolean	equals(Object o)	Compares this filter to the specified object.
boolean	evaluate(Object feature)	Determines whether or not a given feature is 'inside' this filter.
Expression	getExpression()	Returns the expression which represents the null check.
int	hashCode()	Override of hashCode method.
void	setExpression(Expression nullCheck)	Sets the expression which represents the null check.
String	toString()	Returns a string representation of this filter.

Methods inherited from class AbstractFilter

isCompareFilter, isGeometryDistanceFilter, isGeometryFilter, isLogicFilter, isMathFilter, isSimpleFilter

Methods inherited from class FilterAbstract

accepts, eval, eval

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

NullFilterImpl

protected NullFilterImpl(Expression expresion)

Method Details

getExpression

public Expression getExpression()

Returns the expression which represents the null check.

Specified by:

getExpression in interface PropertyIsNull

setExpression

public void setExpression(Expression nullCheck)

Sets the expression which represents the null check.

evaluate

public boolean evaluate(Object feature)

Determines whether or not a given feature is 'inside' this filter.

Specified by:

evaluate in interface Filter

Parameters:

feature - Specified feature to examine.

Returns:

Flag confirming whether or not this feature is inside the filter.

toString

public String toString()

Returns a string representation of this filter.

Overrides:

toString in class Object

Returns:

String representation of the null filter.

equals

public boolean equals(Object o)

Compares this filter to the specified object. Returns true if the passed in object is the same as this filter. Checks to make sure the filter types, and the NullCheckValue are the same.

Overrides:

equals in class Object

Parameters:

o - - the object to compare this LikeFilter against.

Returns:

true if specified object is equal to this filter; false otherwise.

hashCode

public int hashCode()

Override of hashCode method.

Overrides:

hashCode in class Object

Returns:

a hash code value for this geometry filter.

accept

public Object accept(FilterVisitor visitor,
 Object extraData)

Used by FilterVisitors to perform some action on this filter instance. Typicaly used by Filter decoders, but may also be used by any thing which needs infomration from filter structure. Implementations should always call: visitor.visit(this); It is importatant that this is not left to a parent class unless the parents API is identical.

Specified by:

accept in interface Filter

Parameters:

visitor - The visitor which requires access to this filter, the method must call visitor.visit(this);