/**
* 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.engine.operators.singleinput.path;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.bindings.BindingsCollection;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.Literal;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.singleinput.SingleInputOperator;
public class PathLengthZero extends SingleInputOperator{
private static final long serialVersionUID = 1L;
private Variable subject;
private Variable object;
private Set<Literal> allowedSubjects;
private Set<Literal> allowedObjects;
private Set<Bindings> zeroPairs;
public PathLengthZero(Variable subject, Variable object){
this.subject = subject;
this.object = object;
}
public PathLengthZero(Variable subject, Variable object, Set<Literal> allowedSubjects, Set<Literal> allowedObjects){
this.subject = subject;
this.object = object;
this.allowedSubjects = allowedSubjects;
this.allowedObjects = allowedObjects;
}
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
final Iterator<Bindings> itb = bindings.getCollection().iterator();
if(this.zeroPairs==null){
this.zeroPairs = new HashSet<Bindings>();
}
while (itb.hasNext()){
Bindings bind = itb.next();
Bindings newBind = new BindingsCollection();
if((this.allowedSubjects==null || this.allowedSubjects.contains(bind.get(this.subject))) && (this.allowedObjects==null || this.allowedObjects.contains(bind.get(this.subject)))){
newBind.add(this.subject, bind.get(this.subject));
newBind.add(this.object, bind.get(this.subject));
this.zeroPairs.add(newBind);
}
if((this.allowedSubjects==null || this.allowedSubjects.contains(bind.get(this.object))) && (this.allowedObjects==null || this.allowedObjects.contains(bind.get(this.object)))){
newBind = new BindingsCollection();
newBind.add(this.subject, bind.get(this.object));
newBind.add(this.object, bind.get(this.object));
this.zeroPairs.add(newBind);
}
}
final Iterator<Bindings> itz = this.zeroPairs.iterator();
QueryResult result = new QueryResult();
while(itz.hasNext()){
Bindings zeroPath = itz.next();
result.add(zeroPath);
}
return result;
}
}