// Copyright (c) 2006 - 2008, Clark & Parsia, LLC. <http://www.clarkparsia.com>
// This source code is available under the terms of the Affero General Public License v3.
//
// Please see LICENSE.txt for full license terms, including the availability of proprietary exceptions.
// Questions, comments, or requests for clarification: licensing@clarkparsia.com
package com.clarkparsia.pellet.sparqldl.engine;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.mindswap.pellet.KnowledgeBase;
import com.clarkparsia.pellet.sparqldl.model.Query;
import com.clarkparsia.pellet.sparqldl.model.QueryResult;
import com.clarkparsia.pellet.sparqldl.model.QueryResultImpl;
import com.clarkparsia.pellet.sparqldl.model.ResultBinding;
import com.clarkparsia.pellet.sparqldl.model.ResultBindingImpl;
import com.clarkparsia.pellet.sparqldl.model.Query.VarType;
import aterm.ATermAppl;
/**
* <p>
* Title: SimpleQueryEngine
* </p>
* <p>
* Description:
* </p>
* <p>
* Copyright: Copyright (c) 2007
* </p>
* <p>
* Company: Clark & Parsia, LLC. <http://www.clarkparsia.com>
* </p>
*
* @author Petr Kremen
*/
public class SimpleQueryEngine extends AbstractABoxEngineWrapper {
public static final Logger log = Logger.getLogger(QueryEngine.class.getName());
public boolean supports(final Query q) {
return true; // TODO
}
@Override
public QueryResult execABoxQuery(final Query q) {
final QueryResult results = new QueryResultImpl(q);
final KnowledgeBase kb = q.getKB();
long satCount = kb.getABox().stats.satisfiabilityCount;
long consCount = kb.getABox().stats.consistencyCount;
if (q.getDistVars().isEmpty()) {
if (QueryEngine.execBooleanABoxQuery(q)) {
results.add(new ResultBindingImpl());
}
} else {
final Map<ATermAppl, Set<ATermAppl>> varBindings = new HashMap<ATermAppl, Set<ATermAppl>>();
for (final ATermAppl currVar : q
.getDistVarsForType(VarType.INDIVIDUAL)) {
ATermAppl rolledUpClass = q.rollUpTo(currVar,
Collections.EMPTY_SET, false);
if (log.isLoggable( Level.FINER ))
log.finer("Rolled up class " + rolledUpClass);
Set<ATermAppl> inst = kb.getInstances(rolledUpClass);
varBindings.put(currVar, inst);
}
if (log.isLoggable( Level.FINER ))
log.finer("Var bindings: " + varBindings);
final Iterator<ResultBinding> i = new BindingIterator(varBindings);
final Set<ATermAppl> literalVars = q
.getDistVarsForType(VarType.LITERAL);
final Set<ATermAppl> individualVars = q
.getDistVarsForType(VarType.INDIVIDUAL);
boolean hasLiterals = !individualVars.containsAll(literalVars);
if (hasLiterals) {
while (i.hasNext()) {
final ResultBinding b = i.next();
final Iterator<ResultBinding> l = new LiteralIterator(q, b);
while (l.hasNext()) {
ResultBinding mappy = l.next();
boolean queryTrue = QueryEngine.execBooleanABoxQuery(q
.apply(mappy));
if (queryTrue)
results.add(mappy);
}
}
} else {
while (i.hasNext()) {
final ResultBinding b = i.next();
boolean queryTrue = (q.getDistVarsForType(
VarType.INDIVIDUAL).size() == 1)
|| QueryEngine.execBooleanABoxQuery(q.apply(b));
if (queryTrue)
results.add(b);
}
}
}
if (log.isLoggable( Level.FINE )) {
log.fine("Results: "
+ results);
log.fine("Total satisfiability operations: "
+ (kb.getABox().stats.satisfiabilityCount - satCount));
log.fine("Total consistency operations: "
+ (kb.getABox().stats.consistencyCount - consCount));
}
return results;
}
}