Module org.opengis.geoapi

Package org.opengis.filter.capability

Interface AvailableFunction

@UML(identifier="AvailableFunctions",
     specification=ISO_19143)
public interface AvailableFunction

A function that may be used in filter expressions. The description of each function includes a declaration of the return type, the list of arguments with optional names and expected types.

Since:

3.1

See Also:

• FilterCapabilities.getFunctions()

Method Summary

Modifier and Type	Method	Description
default List<? extends ParameterDescriptor<?>>	getArguments()	Returns the list of arguments expected by the function.
LocalName	getName()	Returns the function name.
TypeName	getReturnType()	Returns the type of return value.

Method Details

getName

@UML(identifier="name",
     obligation=MANDATORY,
     specification=ISO_19143)
LocalName getName()

Returns the function name.

Returns:

the function name.

getReturnType

@UML(identifier="returns",
     obligation=MANDATORY,
     specification=ISO_19143)
TypeName getReturnType()

Returns the type of return value.

Returns:

the type of return value.

Departure from OGC/ISO standard for closer integration with the Java environment

OGC/ISO defines the return type as org.opengis.util.ScopedName. However this is at odd with other classes returning type information, which use TypeName.

getArguments

@UML(identifier="arguments",
     obligation=OPTIONAL,
     specification=ISO_19143)
default List<? extends ParameterDescriptor<?>> getArguments()

Returns the list of arguments expected by the function.

Unified parameter API

In GeoAPI, the Argument type defined by ISO 19143 is replaced by ParameterDescriptor in order to provide a single parameter API (see org.opengis.parameter for more information). The mapping from ISO 19143 to GeoAPI is defined in the following table. The equivalences are straightforward except for the types: name is mapped to an Identifier instead of LocalName, and type is mapped to an TypeName instead of ScopedName.

Argument properties mapped to GeoAPI

Argument property	ParameterDescriptor property
name	name
type	valueType

Returns:

arguments that the function accepts.

Departure from OGC/ISO standard for harmonization between different specifications

Usage of the ISO 19143 Argument type has been replaced by usage of the ISO 19111 OperationParameter type in order to provide a unified parameter API.