org.apache.jena.sparql.function.js

Class FunctionJavaScript

java.lang.Object

org.apache.jena.sparql.function.FunctionBase

org.apache.jena.sparql.function.js.FunctionJavaScript

All Implemented Interfaces:

Function

public class FunctionJavaScript
extends FunctionBase

Javascript implemented SPARQL custom functions for ARQ. The JavaScript function is called with arguments which are mapped so that XSD strings, numbers and booleans become the equivalent native JavaScript object, and anything else becomes a NV, a JavaScript object providing access to the RDF features such as datatype. NV.toString() returns a string so a function working with URIs can treat URIs as strings which is natural in JavaScript and aligned to rdfjs/representation-task-force.

Functions are executed in EnvJavaScript. There is a global EnvJavaScript and it can also be set specifically for a query execution. See EnvJavaScript for details of configuration.

Note: there is an attempt to reconstruct the datatype of the result of the function into xsd:integer and xsd:double.

Functions that return null or undefined will result in a ExprEvalException.

See Also:

EnvJavaScript, NV

Constructor Summary

Constructors

Constructor and Description
FunctionJavaScript(String functionName, EnvJavaScript env)

Method Summary

Modifier and Type	Method and Description
void	checkBuild(String uri, ExprList args)
NodeValue	exec(List<NodeValue> args) Function call to a list of evaluated argument values

Methods inherited from class org.apache.jena.sparql.function.FunctionBase

build, evalArgs, exec

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FunctionJavaScript

public FunctionJavaScript(String functionName,
                          EnvJavaScript env)

Method Detail

checkBuild

public void checkBuild(String uri,
                       ExprList args)

Specified by:

checkBuild in class FunctionBase

exec

public NodeValue exec(List<NodeValue> args)

Description copied from class: FunctionBase

Function call to a list of evaluated argument values

Specified by:

exec in class FunctionBase