/**
* 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.rdfs;
import java.util.Collection;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.messages.BoundVariablesMessage;
import lupos.engine.operators.singleinput.ReplaceLit;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
public class RuleDeleteEmptyReplaceLit extends Rule {
@Override
protected void init() {
final ReplaceLit replaceLit = new ReplaceLit();
subGraphMap = new HashMap<BasicOperator, String>();
subGraphMap.put(replaceLit, "replaceLit");
startNode = replaceLit;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
final ReplaceLit replaceLit = (ReplaceLit) mso.get("replaceLit");
// No substitution is left
return (replaceLit.getSubstitutionsLiteralLeft().size() == 0);
}
@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 ReplaceLit replaceLit = (ReplaceLit) mso.get("replaceLit");
final LinkedList<BasicOperator> pres = (LinkedList<BasicOperator>) replaceLit
.getPrecedingOperators();
final LinkedList<OperatorIDTuple> succs = (LinkedList<OperatorIDTuple>) replaceLit
.getSucceedingOperators();
BasicOperator pre;
OperatorIDTuple idTuple;
// Connect all precessors to all successors
for (int i = 0; i < pres.size(); i++) {
for (int a = 0; a < succs.size(); a++) {
idTuple = succs.get(a);
pre = pres.get(i);
pre.addSucceedingOperator(new OperatorIDTuple(idTuple
.getOperator(), idTuple.getId()));
pre.removeSucceedingOperator(replaceLit);
}
}
BasicOperator succ;
// And all successors to all precessors
for (int i = 0; i < succs.size(); i++) {
for (int a = 0; a < pres.size(); a++) {
succ = succs.get(i).getOperator();
succ.addPrecedingOperator(pres.get(a));
succ.removePrecedingOperator(replaceLit);
}
}
rootOperator.deleteParents();
rootOperator.setParents();
rootOperator.detectCycles();
rootOperator.sendMessage(new BoundVariablesMessage());
deleted.add(replaceLit);
if (deleted.size() > 0 || added.size() > 0)
return new Tuple<Collection<BasicOperator>, Collection<BasicOperator>>(
added, deleted);
else
return null;
}
}