/**
* 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.sort.fastsort;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.dbmergesortedds.DBMergeSortedBag;
import lupos.datastructures.dbmergesortedds.SortConfiguration;
import lupos.datastructures.dbmergesortedds.tosort.ToSort.TOSORT;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.Literal;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.index.BasicIndexScan;
import lupos.engine.operators.tripleoperator.TriplePattern;
public class FastSortLazyLiteral extends FastSort {
public FastSortLazyLiteral(final BasicOperator root,
final Collection<TriplePattern> triplePatterns,
final Collection<Variable> sortCriterium) {
super(triplePatterns, sortCriterium);
}
private BasicIndexScan findIndex(final BasicOperator root,
final TriplePattern triplePattern) {
for (final OperatorIDTuple opID : root.getSucceedingOperators()) {
final BasicOperator bo = opID.getOperator();
if (bo instanceof BasicIndexScan) {
if (((BasicIndexScan) bo).getTriplePattern()
.contains(triplePattern))
return (BasicIndexScan) bo;
}
}
return null;
}
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
SortConfiguration sortConfiguration = new SortConfiguration();
sortConfiguration.useExternalMergeSort();
final DBMergeSortedBag<Bindings> bag = new DBMergeSortedBag<Bindings>(
sortConfiguration, new Comparator<Bindings>() {
public int compare(final Bindings arg0, final Bindings arg1) {
for (final Variable var : sortCriterium) {
final Literal l1 = arg0.get(var);
final Literal l2 = arg1.get(var);
if (l1 != null && l2 != null) {
final int compare = l1
.compareToNotNecessarilySPARQLSpecificationConform(l2);
if (compare != 0)
return compare;
} else if (l1 != null)
return -1;
else if (l2 != null)
return 1;
}
return 0;
}
}, Bindings.class);
final Iterator<Bindings> it = bindings.oneTimeIterator();
while (it.hasNext()) {
bag.add(it.next());
}
return QueryResult.createInstance(bag.iterator());
}
}