com.hp.hpl.jena.reasoner.rulesys
Interface BindingEnvironment

public interface BindingEnvironment

Interface through which the current bound values of variables can be found. Many of the details vary between the forward and backward chaining system - this interface is the minimal one needed by most builtins the specific implementations offer richer functionality.

Version:

$Revision: 1.6 $ on $Date: 2003/08/27 13:09:18 $

Author:

Dave Reynolds

Method Summary

boolean	bind(Node var, Node value) Bind a variable in the current envionment to the given value.
Node	getGroundVersion(Node node) Return the most ground version of the node.
Triple	instantiate(TriplePattern pattern) Instantiate a triple pattern against the current environment.

Method Detail

getGroundVersion

public Node getGroundVersion(Node node)

Return the most ground version of the node. If the node is not a variable just return it, if it is a varible bound in this environment return the binding, if it is an unbound variable return the variable.

bind

public boolean bind(Node var,
                    Node value)

Bind a variable in the current envionment to the given value. Checks that the new binding is compatible with any current binding.

Parameters:

var - a Node_RuleVariable defining the variable to bind

value - the value to bind

Returns:

false if the binding fails

instantiate

public Triple instantiate(TriplePattern pattern)

Instantiate a triple pattern against the current environment. This version handles unbound varibles by turning them into bNodes.

Parameters:

pattern - the triple pattern to match

Returns:

a new, instantiated triple