public interface FunctionExpression extends Factory, Function
Functions are published as part of DefaultFuntionFactory using the following workflow:
org.opengis.filter.Function
Factory.getImplementationHints()
used used to
review the hints that are supported by the function implementation.setParameters(List)
is used to supply the argument expressions.setFallbackValue(Literal)
is used to supply a placeholder Literal to be used if the function implementation is not availableorg.opengis.filter.Function DefaultFunctionFactor.If you have a large number of related functions consider the use of
FunctionFactory
.
FunctionFactory
NIL
Modifier and Type | Method and Description |
---|---|
void |
setFallbackValue(Literal fallback)
Fallback value to use in the event the function is unavailable in the requested environment.
|
void |
setParameters(List<Expression> parameters)
Sets the Parameters for the function.
|
getImplementationHints
getFallbackValue, getFunctionName, getName, getParameters
accept, evaluate, evaluate
void setFallbackValue(Literal fallback)
The fallback value is not provided as one of the arguments, as it is an advanced option used in style layer descriptor documents to facilitate interoperability. It allows a user to specify an SQL function, and provide a value to use when the documented is used with a WFS that does not support the provided function.
parameters
- void setParameters(List<Expression> parameters)
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