/**
* Copyright (c) 2013, Institute of Information Systems (Sven Groppe and contributors of LUPOSDATE), University of Luebeck
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice, this list of conditions and the following
* disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other materials provided with the distribution.
* - Neither the name of the University of Luebeck nor the names of its contributors may be used to endorse or promote
* products derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package lupos.rif.operator;
import java.util.HashSet;
import java.util.Set;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.queryresult.QueryResult;
import lupos.rdf.Prefix;
import lupos.rif.IExpression;
import lupos.rif.datatypes.EqualityResult;
import lupos.rif.model.Equality;
import lupos.rif.visitor.ReplaceVarsVisitor;
import com.google.common.collect.Multimap;
public class EqualityFilter extends RuleFilter {
private final Set<Bindings> filteredBindings = new HashSet<Bindings>();
private boolean saveFilteredBindings = true;
private final ReplaceVarsVisitor replace = new ReplaceVarsVisitor();
public EqualityFilter(final IExpression expression,
final Multimap<IExpression, IExpression> eqMap) {
super(expression, eqMap);
}
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
try {
if (bindings instanceof EqualityResult
&& !this.filteredBindings.isEmpty()) {
final QueryResult qr = QueryResult.createInstance();
for (final Bindings bind : this.filteredBindings) {
qr.add(bind);
}
this.saveFilteredBindings = false;
return super.process(qr, operandID);
} else {
return super.process(bindings, operandID);
}
} finally {
this.saveFilteredBindings = true;
}
}
@Override
protected boolean filter(final Bindings bind, final Object result){
final boolean booleanResult = super.filter(bind, result);
if (booleanResult) {
return booleanResult;
} else {
this.replace.bindings = bind;
final Equality replacedEq = (Equality) this.expression.accept(this.replace, null);
return this.equalityMap.get(replacedEq.leftExpr).contains(replacedEq.rightExpr)
|| this.equalityMap.get(replacedEq.rightExpr).contains(replacedEq.leftExpr);
}
}
@Override
protected void onAccepted(final Bindings bind) {
if (!this.saveFilteredBindings) {
this.filteredBindings.remove(bind);
}
}
@Override
protected void onFilteredOut(final Bindings bind) {
if (this.saveFilteredBindings) {
this.filteredBindings.add(bind);
}
}
@Override
public String toString() {
String result = "Equalityfilter\n" + this.expression.toString();
if (this.cardinality >= 0) {
result += "\nCardinality: " + this.cardinality;
}
return result;
}
@Override
public String toString(final Prefix prefixInstance) {
String result = "Equalityfilter\n" + this.expression.toString(prefixInstance);
if (this.cardinality >= 0) {
result += "\nCardinality: " + this.cardinality;
}
return result;
}
}