/**
* 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.singleinput.AddBinding;
import lupos.engine.operators.singleinput.filter.Filter;
import lupos.engine.operators.tripleoperator.patternmatcher.PatternMatcher;
import lupos.misc.Tuple;
import lupos.optimizations.logical.rules.Rule;
/**
* This class implements following rule to replace constant values in Index
* operations:
*
* index(...?X...) index(...constant...) | | filter(?X=constant) =>
* addBinding(?X=constant) | |
*
* Preconditions: - the filter should contain an expression like ?X=constant
*
**/
public class RuleEliminateUnsatisfiableAddFilterSequence extends Rule {
private Variable var;
private Variable varInference;
private Literal constant;
public RuleEliminateUnsatisfiableAddFilterSequence() {
super();
}
@Override
protected void init() {
// Define left side of rule
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(filter, "filter");
subGraphMap.put(add, "add");
startNode = filter;
}
@Override
protected boolean checkPrecondition(final Map<String, BasicOperator> mso) {
final Filter filter = (Filter) mso.get("filter");
if (filter.getPrecedingOperators().size() > 1)
return false;
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();
var = new Variable(varname);
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) {
constant = LazyLiteral.getLiteral(right);
final AddBinding add = (AddBinding) mso.get("add");
if (add.getVar().equals(var)
|| add.getVar().equals(varInference)) {
if (add.getLiteral().equals(constant))
return false;
else
return true;
}
}
}
}
}
return false;
}
@Override
protected 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 Filter filter = (Filter) mso.get("filter");
for (final BasicOperator parent : filter.getPrecedingOperators())
deleteAllAbove(filter, parent, deleted);
final OperatorIDTuple[] opIDTuples = filter.getSucceedingOperators()
.toArray(new OperatorIDTuple[0]);
for (final OperatorIDTuple opIDTuple : opIDTuples)
deleteAllBelow(filter, opIDTuple.getOperator(), deleted);
if (deleted.size() > 0 || added.size() > 0)
return new Tuple<Collection<BasicOperator>, Collection<BasicOperator>>(
added, deleted);
else
return null;
}
public void deleteAllAbove(final BasicOperator parent,
final BasicOperator child, final Collection<BasicOperator> deleted) {
parent.removeSucceedingOperator(child);
if (!(parent instanceof PatternMatcher)) {
// log parent as deleted operator
deleted.add(parent);
// in addition, log all operators (other than child) below parent, that became unrechable
if (parent.getSucceedingOperators().size() > 0) {
final OperatorIDTuple[] opIDTuples =
parent.getSucceedingOperators().toArray(new OperatorIDTuple[0]);
for (final OperatorIDTuple opIDTuple : opIDTuples) {
logDeletedOperatorsBelow(opIDTuple.getOperator(), deleted);
}
}
for (final BasicOperator parentparent : parent
.getPrecedingOperators()) {
deleteAllAbove(parentparent, parent, deleted);
}
}
}
public void logDeletedOperatorsBelow(final BasicOperator parent,
final Collection<BasicOperator> deleted) {
if (parent.getPrecedingOperators().size() < 2) {
deleted.add(parent);
final OperatorIDTuple[] opIDTuples =
parent.getSucceedingOperators().toArray(new OperatorIDTuple[0]);
for (final OperatorIDTuple opIDTuple : opIDTuples) {
logDeletedOperatorsBelow(opIDTuple.getOperator(), deleted);
}
}
}
public void deleteAllBelow(final BasicOperator parent,
final BasicOperator child, final Collection<BasicOperator> deleted) {
if (child.getPrecedingOperators().size() > 1) {
parent.removeSucceedingOperator(child);
child.removePrecedingOperator(parent);
} else {
deleted.add(parent);
final OperatorIDTuple[] opIDTuples = child.getSucceedingOperators()
.toArray(new OperatorIDTuple[0]);
for (final OperatorIDTuple opIDTuple : opIDTuples) {
deleteAllBelow(child, opIDTuple.getOperator(), deleted);
}
}
}
}