/**
* 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.multiinput.optional;
import java.util.Comparator;
import java.util.Iterator;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.Literal;
import lupos.datastructures.queryresult.QueryResult;
import lupos.datastructures.queryresult.QueryResultDebug;
import lupos.engine.operators.Operator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.messages.EndOfEvaluationMessage;
import lupos.engine.operators.messages.Message;
import lupos.engine.operators.multiinput.join.MergeJoin;
import lupos.misc.debug.DebugStep;
public class MergeWithoutSortingOptional extends Optional {
protected QueryResult left = null;
protected QueryResult right = null;
protected Comparator<Bindings> comp = new Comparator<Bindings>() {
@Override
public int compare(final Bindings o1, final Bindings o2) {
for (final Variable var : MergeWithoutSortingOptional.this.intersectionVariables) {
final Literal l1 = o1.get(var);
final Literal l2 = o2.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;
}
};
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
if (this.precedingOperators.size() == 1) {
return bindings;
} else {
if (operandID == 0) {
this.left = bindings;
} else if (operandID == 1) {
this.right = bindings;
} else
System.err.println("MergeWithoutSortingOptional is a binary operator, but received the operand number " + operandID);
if (this.left != null && this.right != null) {
final Iterator<Bindings> currentResult = MergeJoin.mergeOptionalIterator(this.left.oneTimeIterator(), this.right.oneTimeIterator(), this.comp);
if (currentResult != null && currentResult.hasNext()) {
final QueryResult result = QueryResult.createInstance(currentResult);
return result;
} else
return null;
} else
return null;
}
}
@Override
public Message preProcessMessage(final EndOfEvaluationMessage msg) {
if (this.left != null && this.right == null) {
if (this.succeedingOperators.size() > 1)
this.left.materialize();
for (final OperatorIDTuple opId : this.succeedingOperators) {
opId.processAll(this.left);
}
}
return msg;
}
@Override
public Message preProcessMessageDebug(final EndOfEvaluationMessage msg,
final DebugStep debugstep) {
if (this.left != null && this.right == null) {
if (this.succeedingOperators.size() > 1)
this.left.materialize();
for (final OperatorIDTuple opId : this.succeedingOperators) {
final QueryResultDebug qrDebug = new QueryResultDebug(this.left,
debugstep, this, opId.getOperator(), true);
((Operator) opId.getOperator()).processAllDebug(qrDebug, opId
.getId(), debugstep);
}
}
return msg;
}
}