/**
* 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.optimizations.logical.rules.externalontology;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.multiinput.Union;
import lupos.engine.operators.singleinput.generate.Generate;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
public class RuleFactorOutUnionInGenerate extends Rule {
@Override
protected void init() {
final Union union = new Union();
final Generate generate = new Generate();
union.setSucceedingOperator(new OperatorIDTuple(generate, -1));
generate.setPrecedingOperator(union);
subGraphMap = new HashMap<BasicOperator, String>();
subGraphMap.put(union, "union");
subGraphMap.put(generate, "generate");
startNode = union;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
// only one union?
// int number = 0;
// for (final BasicOperator bo : ((Join) mso.get("join"))
// .getPrecedingOperators()) {
// if (bo instanceof Union)
// number++;
// }
// return (number == 1);
return true;
}
@Override
public Tuple<Collection<BasicOperator>, Collection<BasicOperator>> transformOperatorGraph(
final Map<String, BasicOperator> mso,
final BasicOperator rootOperator) {
final Collection<BasicOperator> deleted = new LinkedList<BasicOperator>();
final Collection<BasicOperator> added = new LinkedList<BasicOperator>();
final Union union = (Union) mso.get("union");
final Generate generate = (Generate) mso.get("generate");
final List<BasicOperator> unionOperands = union.getPrecedingOperators();
generate.removePrecedingOperator(union);
deleted.add(union);
boolean firstTime = true;
if (generate.getPrecedingOperators().size() > 0) {
firstTime = false;
}
for (final BasicOperator toMove : unionOperands) {
Generate generateNew;
if (firstTime) {
// use existing generate operator
generateNew = generate;
firstTime = false;
} else {
// clone join operator plus its other operands
generateNew = new Generate();
generateNew.cloneFrom(generate);
added.add(generateNew);
}
generateNew.setPrecedingOperator(toMove);
toMove.setSucceedingOperator(new OperatorIDTuple(generateNew, 0));
}
if (deleted.size() > 0 || added.size() > 0)
return new Tuple<Collection<BasicOperator>, Collection<BasicOperator>>(
added, deleted);
else
return null;
}
}