/**
* 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.HashSet;
import java.util.LinkedList;
import java.util.Map;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.Literal;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.singleinput.Projection;
import lupos.engine.operators.singleinput.ReplaceLit;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
public class RuleReplaceLitOverProjection extends Rule {
@Override
protected void init() {
final ReplaceLit replaceLit = new ReplaceLit();
final Projection projection = new Projection();
replaceLit.setSucceedingOperator(new OperatorIDTuple(projection, -1));
projection.setPrecedingOperator(replaceLit);
subGraphMap = new HashMap<BasicOperator, String>();
subGraphMap.put(replaceLit, "replaceLit");
subGraphMap.put(projection, "projection");
startNode = replaceLit;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
final Projection projection = (Projection) mso.get("projection");
if (projection.getPrecedingOperators().size() == 1)
return true;
else
return false;
}
@Override
public Tuple<Collection<BasicOperator>, Collection<BasicOperator>> transformOperatorGraph(
final Map<String, BasicOperator> mso,
final BasicOperator rootOperator) {
final ReplaceLit replaceLit = (ReplaceLit) mso.get("replaceLit");
final Projection projection = (Projection) mso.get("projection");
final Object[] projectionVars = projection.getProjectedVariables()
.toArray();
final LinkedList<Variable> replaceLitLeft = replaceLit
.getSubstitutionsLiteralLeft();
final LinkedList<Literal> replaceLitRight = replaceLit
.getSubstitutionsLiteralRight();
Variable var;
Literal lit;
// Delete all not projected Tupels from ReplaceLit
for (int i = 0; i < replaceLitLeft.size(); i++) {
var = replaceLitLeft.get(i);
if (!arrayContains(projectionVars, var)) {
lit = replaceLitRight.get(i);
replaceLit.removeSubstitution(var, lit);
}
}
final LinkedList<BasicOperator> pres = (LinkedList<BasicOperator>) replaceLit
.getPrecedingOperators();
final LinkedList<OperatorIDTuple> succs = (LinkedList<OperatorIDTuple>) projection
.getSucceedingOperators();
final int index = replaceLit.getOperatorIDTuple(projection).getId();
BasicOperator pre;
// Connect the ReplaceLit precessors directly to the Projection
for (int i = pres.size() - 1; i >= 0; i--) {
pre = pres.get(i);
projection.addPrecedingOperator(pre);
pre.removeSucceedingOperator(replaceLit);
pre.addSucceedingOperator(new OperatorIDTuple(projection, index));
}
// Make ReplaceLit the successor of Projection
projection.removePrecedingOperator(replaceLit);
projection.setSucceedingOperator(new OperatorIDTuple(replaceLit, 0));
replaceLit.setPrecedingOperator(projection);
final HashSet<Variable> hsv = new HashSet<Variable>();
hsv.addAll(projection.getIntersectionVariables());
replaceLit.setIntersectionVariables(hsv);
replaceLit.setUnionVariables(hsv);
// Connect ReplaceLit to the Projections successors instead of him
replaceLit.setSucceedingOperators(succs);
BasicOperator succ;
for (int i = succs.size() - 1; i >= 0; i--) {
succ = succs.get(i).getOperator();
succ.removePrecedingOperator(projection);
succ.addPrecedingOperator(replaceLit);
}
rootOperator.deleteParents();
rootOperator.setParents();
rootOperator.detectCycles();
// should have been done manually: rootOperator.sendMessage(new
// BoundVariablesMessage());
return null;
}
private boolean arrayContains(final Object[] vars, final Variable var) {
for (int i = 0; i < vars.length; i++) {
System.out.println(vars[i].toString() + "," + var.toString());
if (vars[i].equals(var))
return true;
}
return false;
}
}