/**
* 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.modifiers.distinct;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.queryresult.ParallelIterator;
import lupos.datastructures.queryresult.ParallelIteratorMultipleQueryResults;
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.ComputeIntermediateResultMessage;
import lupos.engine.operators.messages.EndOfEvaluationMessage;
import lupos.engine.operators.messages.Message;
import lupos.misc.debug.DebugStep;
/**
* This class is similar to BlockingDistinct, but adds bindings to its set only
* after EndOfStreamMessage or ComputeIntermediateResultMessage. In this way, no
* errors occur for Stream-processing with windows!
*
*/
public class LazyBlockingDistinct extends Distinct {
protected final Set<Bindings> bindings;
protected ParallelIteratorMultipleQueryResults operandsData;
public LazyBlockingDistinct() {
this.bindings = new HashSet<Bindings>();
}
public LazyBlockingDistinct(final Set<Bindings> bindings) {
this.bindings = bindings;
}
@Override
public synchronized QueryResult process(final QueryResult queryResult,
final int operandID) {
this.operandsData.addQueryResult(queryResult);
return null;
}
protected ParallelIterator<Bindings> getIterator() {
final Iterator<Bindings> itb = this.bindings.iterator();
return new ParallelIterator<Bindings>() {
@Override
public void close() {
// derived classes may override the above method in order to
// release some resources here!
}
@Override
public boolean hasNext() {
return itb.hasNext();
}
@Override
public Bindings next() {
return itb.next();
}
@Override
public void remove() {
itb.remove();
}
};
}
@Override
public Message preProcessMessage(final EndOfEvaluationMessage msg) {
this.bindings.clear();
if (this.operandsData != null) {
final Iterator<Bindings> itb2 = this.operandsData.getQueryResult().oneTimeIterator();
while (itb2.hasNext())
this.bindings.add(itb2.next());
}
final QueryResult qr = QueryResult.createInstance(getIterator());
if (this.succeedingOperators.size() > 1)
qr.materialize();
for (final OperatorIDTuple opId : this.succeedingOperators) {
opId.processAll(qr);
}
return msg;
}
@Override
public Message preProcessMessage(final ComputeIntermediateResultMessage msg) {
this.deleteAllAtSucceedingOperators();
preProcessMessage(new EndOfEvaluationMessage());
return msg;
}
@Override
public QueryResult deleteQueryResult(final QueryResult queryResult,
final int operandID) {
this.operandsData.removeAll(queryResult);
return null;
}
@Override
public void deleteQueryResult(final int operandID) {
this.bindings.clear();
if (this.operandsData != null)
this.operandsData.release();
this.operandsData = null;
}
@Override
protected boolean isPipelineBreaker() {
return true;
}
@Override
public Message preProcessMessageDebug(
final ComputeIntermediateResultMessage msg,
final DebugStep debugstep) {
this.deleteAllDebugAtSucceedingOperators(debugstep);
preProcessMessageDebug(new EndOfEvaluationMessage(), debugstep);
return msg;
}
@Override
public Message preProcessMessageDebug(final EndOfEvaluationMessage msg,
final DebugStep debugstep) {
this.bindings.clear();
if (this.operandsData != null) {
final Iterator<Bindings> itb2 = this.operandsData.getQueryResult().oneTimeIterator();
while (itb2.hasNext())
this.bindings.add(itb2.next());
}
final QueryResult qr = QueryResult.createInstance(getIterator());
if (this.succeedingOperators.size() > 1)
qr.materialize();
for (final OperatorIDTuple opId : this.succeedingOperators) {
final QueryResultDebug qrDebug = new QueryResultDebug(qr,
debugstep, this, opId.getOperator(), true);
((Operator) opId.getOperator()).processAllDebug(qrDebug, opId
.getId(), debugstep);
}
return msg;
}
}