/**
* 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.join;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.bindings.BindingsFactory;
import lupos.datastructures.items.BindingsComparator;
import lupos.datastructures.queryresult.ParallelIterator;
import lupos.datastructures.queryresult.QueryResult;
import lupos.datastructures.queryresult.SIPParallelIterator;
import lupos.engine.operators.messages.BindingsFactoryMessage;
import lupos.engine.operators.messages.Message;
import lupos.engine.operators.messages.StartOfEvaluationMessage;
public class MergeJoinWithoutSorting extends Join {
private static final long serialVersionUID = 5051512203278340771L;
protected QueryResult left = null;
protected QueryResult right = null;
protected BindingsComparator comp = new BindingsComparator();
protected BindingsFactory bindingsFactory;
/**
* This method pre-processes the StartOfStreamMessage
*
* @param msg
* the message to be pre-processed
* @return the pre-processed message
*/
@Override
public Message preProcessMessage(final StartOfEvaluationMessage msg) {
if (this.left != null) {
this.left.release();
}
if (this.right != null) {
this.right.release();
}
this.left = null;
this.right = null;
return super.preProcessMessage(msg);
}
@Override
public Message preProcessMessage(final BindingsFactoryMessage msg){
this.bindingsFactory = msg.getBindingsFactory();
return msg;
}
@Override
public QueryResult process(final QueryResult bindings, final int operandID) {
if (operandID == 0) {
this.left = bindings;
} else if (operandID == 1) {
this.right = bindings;
} else {
System.err.println("MergeJoin is a binary operator, but received the operand number "
+ operandID);
}
if (this.left != null && this.right != null) {
this.comp.setVariables(this.intersectionVariables);
final ParallelIterator<Bindings> currentResult = (this.intersectionVariables
.size() == 0) ? MergeJoin.cartesianProductIterator(this.left, this.right) :
MergeJoin.mergeJoinIterator(this.left.oneTimeIterator(), this.right.oneTimeIterator(), this.comp, this.intersectionVariables, this.bindingsFactory);
if (currentResult != null && currentResult.hasNext()) {
final QueryResult result = QueryResult
.createInstance(new SIPParallelIterator<Bindings, Bindings>() {
int number = 0;
@Override
public void close() {
currentResult.close();
}
@Override
public boolean hasNext() {
if (!currentResult.hasNext()) {
MergeJoinWithoutSorting.this.realCardinality = this.number;
this.close();
}
return currentResult.hasNext();
}
@Override
public Bindings next() {
final Bindings b = currentResult.next();
if (b != null) {
this.number++;
}
if (!currentResult.hasNext()) {
MergeJoinWithoutSorting.this.realCardinality = this.number;
this.close();
}
return b;
}
public Bindings getNext(final Bindings k) {
@SuppressWarnings("unchecked")
final Bindings b = ((SIPParallelIterator<Bindings, Bindings>) currentResult)
.next(k);
if (b != null) {
this.number++;
}
if (!currentResult.hasNext()) {
MergeJoinWithoutSorting.this.realCardinality = this.number;
this.close();
}
return b;
}
@Override
public void remove() {
currentResult.remove();
}
@Override
public void finalize() {
this.close();
}
@Override
public Bindings next(final Bindings k) {
if (currentResult instanceof SIPParallelIterator) {
return this.getNext(k);
} else {
return this.next();
}
}
});
return result;
} else {
this.left.release();
this.right.release();
return null;
}
} else {
return null;
}
}
}