com.bigdata.relation.rule.eval.ISolution Maven / Gradle / Ivy
/*
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Jun 24, 2008
*/
package com.bigdata.relation.rule.eval;
import com.bigdata.bop.IBindingSet;
import com.bigdata.relation.rule.IRule;
/**
* A solution bundles together any of (a) the materialized element corresponding
* to the bindings on the head of an {@link IRule}; (b) the {@link IBindingSet}
* used to generate that solution; and (c) the {@link IRule} from which those
* bindings were computed. All data are optional. Which data are included
* depends on a set of bit flags known to the {@link IJoinNexus} implementation
* and the behavior of its {@link IJoinNexus#newSolution(IRule, IBindingSet)}
* implementation.
*
* Note: The {@link IBindingSet} is useful both for high-level query and to
* materialize the justifications for the entailments. The RDF DB uses this for
* to maintain a justifications index in support of truth maintenance.
*
* @author Bryan Thompson
* @version $Id$
* @param
* The generic type of elements materialized from the head of the
* rule.
*/
public interface ISolution {
/**
* Return the element materialized from the head of the rule given a set of
* {@link IBindingSet bindings} for that rule (optional operation).
*
* @return The element -or- null if the element was not
* requested.
*/
public E get();
/**
* Return the {@link IRule} that generated this solution (optional
* operation).
*
* @return The {@link IRule} -or- null if the rule was not
* requested.
*/
public IRule getRule();
/**
* Return the {@link IBindingSet} for this solution (optional operation).
*
* @return The {@link IBindingSet}.
*
* @return The {@link IBindingSet} -or- null if the binding
* set was not requested.
*/
public IBindingSet getBindingSet();
}