/**
* 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.rif.operator;
import java.util.Arrays;
import java.util.HashSet;
import lupos.datastructures.bindings.Bindings;
import lupos.datastructures.bindings.BindingsFactory;
import lupos.datastructures.items.Triple;
import lupos.datastructures.items.Variable;
import lupos.datastructures.items.literal.LiteralFactory;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.index.BasicIndexScan;
import lupos.engine.operators.index.Dataset;
import lupos.engine.operators.index.Indices;
import lupos.engine.operators.index.Root;
import lupos.engine.operators.messages.BindingsFactoryMessage;
import lupos.engine.operators.messages.BoundVariablesMessage;
import lupos.engine.operators.messages.Message;
import lupos.engine.operators.stream.TripleDeleter;
import lupos.engine.operators.tripleoperator.TripleConsumer;
import lupos.engine.operators.tripleoperator.TripleConsumerDebug;
import lupos.misc.debug.DebugStep;
import lupos.rdf.Prefix;
public class BooleanIndexScan extends BasicIndexScan implements TripleConsumer, TripleConsumerDebug, TripleDeleter {
protected BindingsFactory bindingsFactory;
public BooleanIndexScan(final Root root) {
super(root);
this.triplePatterns = Arrays.asList();
}
@Override
public Message preProcessMessage(final BoundVariablesMessage msg) {
final BoundVariablesMessage result = new BoundVariablesMessage(msg);
result.getVariables().add(new Variable("@boolean"));
this.intersectionVariables = new HashSet<Variable>(result.getVariables());
this.unionVariables = this.intersectionVariables;
return result;
}
@Override
public Message preProcessMessage(final BindingsFactoryMessage msg){
this.bindingsFactory = msg.getBindingsFactory();
return msg;
}
private QueryResult createQueryResult(){
final QueryResult result = QueryResult.createInstance();
final Bindings bind = this.bindingsFactory.createInstance();
bind.add(new Variable("@boolean"), LiteralFactory.createLiteral("true"));
result.add(bind);
return result;
}
@Override
public QueryResult process(final Dataset dataset) {
// leitet ein QueryResult mit einem Binding weiter
return this.createQueryResult();
}
@Override
public QueryResult join(final Indices indices, final Bindings bindings) {
return null;
}
@Override
public String toString() {
return "BooleanIndex";
}
@Override
public String toString(final Prefix prefixInstance) {
return this.toString();
}
private boolean firstTime = true;
@Override
public void deleteTriple(final Triple triple) {
}
@Override
public void deleteTripleDebug(final Triple triple, final DebugStep debugstep) {
}
@Override
public void consume(final Triple triple) {
if(this.firstTime){
this.processAtSucceedingOperators(this.createQueryResult());
this.firstTime = false;
}
}
@Override
public void consumeDebug(final Triple triple, final DebugStep debugstep) {
if(this.firstTime){
this.processAtSucceedingOperatorsDebug(this.createQueryResult(), debugstep);
this.firstTime = false;
}
}
@Override
public boolean joinOrderToBeOptimized(){
return false;
}
}