com.hp.hpl.jena.sparql.function

Class FunctionBase

java.lang.Object

com.hp.hpl.jena.sparql.function.FunctionBase

All Implemented Interfaces:

Function

Direct Known Subclasses:

FN_StrConcat, FN_StrSubstring, FunctionBase0, FunctionBase1, FunctionBase2, FunctionBase3, FunctionBase4, strjoin, substring

public abstract class FunctionBase
extends Object
implements Function

Interface to value-testing extensions to the expression evaluator.

Constructor Summary

Constructors

Constructor and Description
FunctionBase()

Method Summary

Methods

Modifier and Type	Method and Description
void	build(String uri, ExprList args) Called during query plan construction immediately after the construction of the extension instance.
abstract void	checkBuild(String uri, ExprList args)
NodeValue	exec(Binding binding, ExprList args, String uri, FunctionEnv env) Test a list of values - argument will not be null but may have the wrong number of arguments.
abstract NodeValue	exec(List<NodeValue> args) Function call to a list of evaluated argument values
Context	getContext() Return the Context object for this execution

Methods inherited from class java.lang.Object

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

Constructor Detail

FunctionBase

public FunctionBase()

Method Detail

build

public final void build(String uri,
         ExprList args)

Description copied from interface: Function

Called during query plan construction immediately after the construction of the extension instance. Can throw ExprBuildException if something is wrong (like wrong number of arguments).

Specified by:

build in interface Function

args - The parsed arguments

exec

public NodeValue exec(Binding binding,
             ExprList args,
             String uri,
             FunctionEnv env)

Description copied from interface: Function

Test a list of values - argument will not be null but may have the wrong number of arguments. FunctionBase provides a more convenient way to implement a function. Can throw ExprEvalsException if something goes wrong.

Specified by:

exec in interface Function

Parameters:

binding - The current solution

args - A list of unevaluated expressions

uri - The name of this

env - The execution context

Returns:

NodeValue - a value

getContext

public Context getContext()

Return the Context object for this execution

exec

public abstract NodeValue exec(List<NodeValue> args)

Function call to a list of evaluated argument values

checkBuild

public abstract void checkBuild(String uri,
              ExprList args)