org.geotools.filter
Class FallbackFunction

Object
  ExpressionAbstract
      DefaultExpression
          FunctionExpressionImpl
              FallbackFunction

All Implemented Interfaces:

Factory, ExpressionType, 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 class DefaultExpression

expressionType, permissiveConstruction

Fields inherited from interface ExpressionType

ATTRIBUTE, ATTRIBUTE_DOUBLE, ATTRIBUTE_GEOMETRY, ATTRIBUTE_INTEGER, ATTRIBUTE_STRING, ATTRIBUTE_UNDECLARED, FUNCTION, LITERAL_DOUBLE, LITERAL_GEOMETRY, LITERAL_INTEGER, LITERAL_LONG, LITERAL_STRING, LITERAL_UNDECLARED, MATH_ADD, MATH_DIVIDE, MATH_MULTIPLY, MATH_SUBTRACT

Fields inherited from interface Expression

NIL

Constructor Summary

FallbackFunction(Name name, List params, Literal fallback)

FallbackFunction(String name, List params, Literal fallback)

Method Summary

Object	evaluate(Object object) This method checks if the object is an instance of Feature and if so, calls through to #evaluate(Feature).
Object	evaluate(Object object, Class context) Default implementation delegates handling of context conversion to Value utility class.
int	getArgCount() Gets the number of arguments that are set.

Methods inherited from class FunctionExpressionImpl

accept, equals, functionName, getArgs, getExpression, getFallbackValue, getFunctionName, getImplementationHints, getName, getParameters, getType, setArgs, setFallbackValue, setName, setParameters, toString

Methods inherited from class DefaultExpression

accept, evaluate, getValue, isAttributeExpression, isExpression, isFunctionExpression, isGeometryExpression, isLiteralExpression, isMathExpression, isMathExpression

Methods inherited from class ExpressionAbstract

eval, eval

Methods inherited from class Object

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

Methods inherited from interface Expression

accept, evaluate, getValue

Constructor Detail

FallbackFunction

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

FallbackFunction

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

Method Detail

getArgCount

public int getArgCount()

Description copied from class: FunctionExpressionImpl

Gets the number of arguments that are set.

Specified by:

getArgCount in interface FunctionExpression

Overrides:

getArgCount in class FunctionExpressionImpl

Returns:

the number of args.

evaluate

public Object evaluate(Object object)

Description copied from class: DefaultExpression

This method checks if the object is an instance of Feature and if so, calls through to #evaluate(Feature). This is done to maintain backwards compatability with previous version of Expression api which depended on Feature. If the object is not an instance of feature the super implementation is called.

Specified by:

evaluate in interface Expression

Overrides:

evaluate in class DefaultExpression

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.