Package org.geotools.filter.function

Class Collection_UniqueFunction

Object

ExpressionAbstract

DefaultExpression

FunctionExpressionImpl

Collection_UniqueFunction

All Implemented Interfaces:

Expression, Function, FunctionExpression, Factory

public class Collection_UniqueFunction
extends FunctionExpressionImpl

Calculates the unique value of an attribute for a given FeatureCollection and Expression.

Since:

2.2M2

Author:

Cory Horner

Field Summary

Fields

Modifier and Type	Field	Description
static FunctionName	NAME

Fields inherited from class FunctionExpressionImpl

fallback, functionName, name, params

Fields inherited from interface Expression

NIL

Constructor Summary

Constructors

Constructor	Description
Collection_UniqueFunction()	Creates a new instance of Collection_UniqueFunction

Method Summary

Modifier and Type	Method	Description
Object	evaluate(Object feature)	Subclass should override, default implementation returns null.
void	setExpression(Expression e)
void	setParameters(List<Expression> args)	The provided arguments are evaulated with respect to the FeatureCollection.

Methods inherited from class FunctionExpressionImpl

accept, equals, functionName, getExpression, getFallbackValue, getFunctionName, getImplementationHints, getName, getParameters, hashCode, setFallbackValue, toString

Methods inherited from class DefaultExpression

isAttributeExpression, isExpression, isFunctionExpression, isGeometryExpression, isLiteralExpression, isMathExpression

Methods inherited from class ExpressionAbstract

evaluate

Methods inherited from class Object

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

Methods inherited from interface Expression

evaluate

Field Details

NAME

public static FunctionName NAME

Constructor Details

Collection_UniqueFunction

public Collection_UniqueFunction()

Creates a new instance of Collection_UniqueFunction

Method Details

setParameters

public void setParameters(List<Expression> args)

The provided arguments are evaulated with respect to the FeatureCollection.

For an aggregate function (like unique) please use the WFS mandated XPath syntax to refer to featureMember content.

To refer to all 'X': featureMember/asterisk/X

Specified by:

setParameters in interface FunctionExpression

Overrides:

setParameters in class FunctionExpressionImpl

evaluate

public Object evaluate(Object feature)

Description copied from class: ExpressionAbstract

Subclass should override, default implementation returns null.

Specified by:

evaluate in interface Expression

Overrides:

evaluate in class FunctionExpressionImpl

Returns:

default implementation returns null

setExpression

public void setExpression(Expression e)