com.hp.hpl.jena.reasoner.rulesys.builtins
Class ListLength

java.lang.Object
  com.hp.hpl.jena.reasoner.rulesys.builtins.BaseBuiltin
      com.hp.hpl.jena.reasoner.rulesys.builtins.ListLength

All Implemented Interfaces:

Builtin

public class ListLength
extends BaseBuiltin

Bind the second arg to the length of the first arg treated as a list. Fails if the list is malformed.

Version:

$Revision: 1.9 $ on $Date: 2008/01/02 12:06:20 $

Author:

Dave Reynolds

Field Summary

Fields inherited from class com.hp.hpl.jena.reasoner.rulesys.builtins.BaseBuiltin

BASE_URI

Constructor Summary

ListLength()

Method Summary

boolean	bodyCall(Node[] args, int length, RuleContext context) This method is invoked when the builtin is called in a rule body.
int	getArgLength() Return the expected number of arguments for this functor or 0 if the number is flexible.
java.lang.String	getName() Return a name for this builtin, normally this will be the name of the functor that will be used to invoke it.

Methods inherited from class com.hp.hpl.jena.reasoner.rulesys.builtins.BaseBuiltin

checkArgs, getArg, getURI, headAction, isMonotonic, isSafe

Methods inherited from class java.lang.Object

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

Constructor Detail

ListLength

public ListLength()

Method Detail

getName

public java.lang.String getName()

Return a name for this builtin, normally this will be the name of the functor that will be used to invoke it.

getArgLength

public int getArgLength()

Return the expected number of arguments for this functor or 0 if the number is flexible.

Specified by:

getArgLength in interface Builtin

Overrides:

getArgLength in class BaseBuiltin

bodyCall

public boolean bodyCall(Node[] args,
                        int length,
                        RuleContext context)

This method is invoked when the builtin is called in a rule body.

Specified by:

bodyCall in interface Builtin

Overrides:

bodyCall in class BaseBuiltin

Parameters:

args - the array of argument values for the builtin, this is an array of Nodes, some of which may be Node_RuleVariables.

length - the length of the argument list, may be less than the length of the args array for some rule engines

context - an execution context giving access to other relevant data

Returns:

return true if the buildin predicate is deemed to have succeeded in the current environment