package de.unikiel.inf.comsys.neo4j.inference.rules;
/*
* #%L
* neo4j-sparql-extension
* %%
* Copyright (C) 2014 Niclas Hoyer
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program. If not, see
* <http://www.gnu.org/licenses/gpl-3.0.html>.
* #L%
*/
import java.util.List;
import org.openrdf.query.algebra.QueryModelNode;
import org.openrdf.query.algebra.StatementPattern;
import org.openrdf.query.algebra.Union;
/**
* A rule that transforms a statement pattern according to the SubPropertyOf
* OWL-2 Axiom.
*
* @see
* <a href="http://www.w3.org/TR/owl2-semantics/#Object_Property_Expression_Axioms">
* OWL-2 property expression axioms
* </a>
*/
public class SubPropertyOf extends AbstractRule {
private final String op1;
private final String op2;
/**
* Create a new subproperty rule.
*
* @param op1 the subproperty
* @param op2 the superproperty
*/
public SubPropertyOf(String op1, String op2) {
this.op1 = op1;
this.op2 = op2;
}
/**
* Returns true if this rule is applicable to a node.
*
* @param node to a node
* @return true if the rule is applicable, false otherwise
*/
@Override
public boolean canApply(StatementPattern node) {
String op = getPredicate(node);
// check that the predicate is the superproperty
return op != null && op.equals(op2);
}
/**
* Transform a statement pattern according to OWL-2 subproperty axiom.
*
* @param node the node to transform
* @return list of nodes to visit next
*/
@Override
public List<QueryModelNode> apply(StatementPattern node) {
List<QueryModelNode> next = newNextList();
StatementPattern left = node.clone();
// replace the predicate with the subproperty
StatementPattern right
= new StatementPattern(
node.getSubjectVar(),
new ConstVar(vf.createURI(op1)),
node.getObjectVar(),
node.getContextVar());
node.replaceWith(
new Union(left, right));
next.add(left);
next.add(right);
return next;
}
@Override
public String toString() {
return "SubPropertyOf(<" + op1 + "> <" + op2 + ">)";
}
}