org.geotools.filter

Class FallbackFunction

Object

ExpressionAbstract

DefaultExpression

FunctionExpressionImpl

FallbackFunction

All Implemented Interfaces:

Factory, FunctionExpression, Expression, Function

public class FallbackFunction
extends FunctionExpressionImpl

A placeholder class used to track a function the user requested that is not supported by our java implementation.

This can be used to construct expressions that are to be executed by another systems (say as SQL or as a WFS request).

Author:

Jody Garnett

Field Summary

Fields inherited from class FunctionExpressionImpl

fallback, functionName, name, params

Fields inherited from interface Expression

NIL

Constructor Summary

Constructors

Constructor and Description
FallbackFunction(Name name, List params, Literal fallback)
FallbackFunction(String name, List params, Literal fallback)

Method Summary

Modifier and Type	Method and Description
Object	evaluate(Object object) Subclass should override, default implementation returns null.
Object	evaluate(Object object, Class context) Default implementation delegates handling of context conversion to Value utility class.

Methods inherited from class FunctionExpressionImpl

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

Methods inherited from class DefaultExpression

isAttributeExpression, isExpression, isFunctionExpression, isGeometryExpression, isLiteralExpression, isMathExpression

Methods inherited from class Object

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

Constructor Detail

FallbackFunction

public FallbackFunction(String name,
                        List params,
                        Literal fallback)

FallbackFunction

public FallbackFunction(Name name,
                        List params,
                        Literal fallback)

Method Detail

evaluate

public Object evaluate(Object object)

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

evaluate

public Object evaluate(Object object,
                       Class context)

Description copied from class: ExpressionAbstract

Default implementation delegates handling of context conversion to Value utility class.

Subclasses are expected to make use of the Value utility class (as the easiest way to provide value morphing in confirmance with the Filter specification).

Specified by:

evaluate in interface Expression

Overrides:

evaluate in class ExpressionAbstract

Parameters:

object - The object to evaluate the expression against.

context - The type of the resulting value of the expression.

Returns:

Evaluates the given expression based on the content of the given object an an instance of context.