/**
* 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.Map;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.VariableInInferenceRule;
import lupos.datastructures.items.literal.LazyLiteral;
import lupos.datastructures.items.literal.Literal;
import lupos.engine.operators.BasicOperator;
import lupos.engine.operators.OperatorIDTuple;
import lupos.engine.operators.multiinput.join.Join;
import lupos.engine.operators.singleinput.AddBinding;
import lupos.engine.operators.singleinput.filter.Filter;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
public class RuleEliminateUnsatisfiableFilterAfterAdd extends Rule {
private AddBinding add;
@Override
protected void init() {
final AddBinding add = new AddBinding(null, null);
final Filter filter = new Filter();
add.setSucceedingOperator(new OperatorIDTuple(filter, -1));
filter.setPrecedingOperator(add);
subGraphMap = new HashMap<BasicOperator, String>();
subGraphMap.put(add, "add");
subGraphMap.put(filter, "filter");
startNode = add;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
add = (AddBinding) mso.get("add");
final Filter filter = (Filter) mso.get("filter");
if(filter.getPrecedingOperators().size()>1)
return false;
do {
Variable v=add.getVar();
Literal l=add.getLiteral();
lupos.sparql1_1.Node n = filter.getNodePointer();
if (n.jjtGetNumChildren() > 0) {
n = n.jjtGetChild(0);
if (n instanceof lupos.sparql1_1.ASTEqualsNode) {
lupos.sparql1_1.Node left = n.jjtGetChild(0);
lupos.sparql1_1.Node right = n.jjtGetChild(1);
if (right instanceof lupos.sparql1_1.ASTVar) {
final lupos.sparql1_1.Node tmp = left;
left = right;
right = tmp;
}
if (left instanceof lupos.sparql1_1.ASTVar) {
final String varname = ((lupos.sparql1_1.ASTVar) left)
.getName();
Variable var = new Variable(varname);
VariableInInferenceRule varInference = new VariableInInferenceRule(varname);
if (right instanceof lupos.sparql1_1.ASTQName
|| right instanceof lupos.sparql1_1.ASTQuotedURIRef
|| right instanceof lupos.sparql1_1.ASTFloatingPoint
|| right instanceof lupos.sparql1_1.ASTInteger
|| right instanceof lupos.sparql1_1.ASTStringLiteral
|| right instanceof lupos.sparql1_1.ASTDoubleCircumflex) {
Literal constant = LazyLiteral.getLiteral(right);
if(var.equals(v) || varInference.equals(v)){
if(!l.equals(constant))
return true;
}
} else return false;
} else return false;
} else return false;
} else return false;
BasicOperator bo=add.getPrecedingOperators().get(0);
if(bo instanceof AddBinding)
add=(AddBinding)bo;
else return false;
} while(add.getPrecedingOperators().size()==1);
return false;
}
@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>();
// remove addBinding
for (BasicOperator op: add.getPrecedingOperators()) {
op.removeSucceedingOperator(add);
}
// perform depth first search to remove filter and following operators
deleteSubGraph(add, deleted);
if (deleted.size() > 0 || added.size() > 0)
return new Tuple<Collection<BasicOperator>, Collection<BasicOperator>>(
added, deleted);
else
return null;
}
private void deleteSubGraph(final BasicOperator currentOp, final Collection<BasicOperator> deleted) {
// current op was deleted from graph
deleted.add(currentOp);
// as long as there are successors, detach the first successor of current operator
while (currentOp.getSucceedingOperators().size() > 0) {
final BasicOperator nextOp = currentOp.getSucceedingOperators().get(0).getOperator();
currentOp.removeSucceedingOperator(nextOp);
nextOp.removePrecedingOperator(currentOp);
if (nextOp.getPrecedingOperators().size() == 0) {
// walk the graph recursively if no predecessors are left
deleteSubGraph(nextOp, deleted);
} else if (nextOp instanceof Join) {
// nextOp is a join: check if all remaining predecessors have same operand id
int opId = -1;
for (BasicOperator pred: nextOp.getPrecedingOperators()) {
for (OperatorIDTuple tuple: pred.getSucceedingOperators()) {
if (tuple.getOperator() == nextOp) {
if (opId == -1) {
opId = tuple.getId();
} else if (opId != tuple.getId()) {
return;
}
}
}
}
// all predecessors have same id: delete the join
for (BasicOperator pred: nextOp.getPrecedingOperators()) {
pred.removeSucceedingOperator(nextOp);
pred.addSucceedingOperators(nextOp.getSucceedingOperators());
for (OperatorIDTuple tuple: nextOp.getSucceedingOperators()) {
tuple.getOperator().addPrecedingOperator(pred);
}
}
for (OperatorIDTuple tuple: nextOp.getSucceedingOperators()) {
tuple.getOperator().removePrecedingOperator(nextOp);
}
deleted.add(nextOp);
}
}
}
}