/**
* 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.Iterator;
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.Literal;
import lupos.datastructures.items.literal.URILiteral;
import lupos.datastructures.queryresult.QueryResult;
import lupos.engine.operators.Operator;
import lupos.engine.operators.OperatorIDTuple;
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.misc.util.ImmutableIterator;
import lupos.rdf.Prefix;
import lupos.rif.builtin.RIFBuiltinFactory;
import lupos.rif.model.Constant;
import lupos.rif.model.External;
import lupos.rif.model.RuleVariable;
public class IteratorIndexScan extends BasicIndexScan implements TripleConsumer, TripleConsumerDebug, TripleDeleter {
private static final long serialVersionUID = -2452758087959813203L;
private final External external;
protected BindingsFactory bindingsFactory;
public IteratorIndexScan(final Root root, final External iteratorPredicate) {
super(root);
this.external = iteratorPredicate;
}
@Override
public Message preProcessMessage(final BoundVariablesMessage msg) {
final BoundVariablesMessage result = new BoundVariablesMessage(msg);
result.getVariables().add(
((RuleVariable) this.external.termParams.get(0)).getVariable());
return result;
}
@Override
public Message preProcessMessage(final BindingsFactoryMessage msg){
this.bindingsFactory = msg.getBindingsFactory();
return msg;
}
private Iterator<Bindings> newBindingIterator() {
final Iterator<Literal> litIt = this.getLiteralIterator();
// Variable steht an erster Stelle des Pr�dikats
final Variable varToBind = (Variable) this.external.termParams.get(0)
.evaluate(this.bindingsFactory.createInstance());
return new ImmutableIterator<Bindings>() {
@Override
public boolean hasNext() {
return litIt.hasNext();
}
@Override
public Bindings next() {
final Bindings bind = IteratorIndexScan.this.bindingsFactory.createInstance();
bind.add(varToBind, litIt.next());
return bind;
}
};
}
private Iterator<Literal> getLiteralIterator() {
// External in IteratorPredicates suchen und dann Parameter 1-x
// (evaluiert) �bergeben
final Literal[] args = new Literal[this.external.termParams.size() - 1];
for (int i = 1; i < this.external.termParams.size(); i++) {
args[i - 1] = (Literal) this.external.termParams.get(i).evaluate(
this.bindingsFactory.createInstance());
}
return RIFBuiltinFactory.getIterator(
(URILiteral) ((Constant) this.external.termName).getLiteral(), args);
}
@Override
public QueryResult process(final Dataset dataset) {
final Iterator<Bindings> bindIt = this.newBindingIterator();
while (bindIt.hasNext()) {
final Bindings bind = bindIt.next();
for (final OperatorIDTuple oid : this.getSucceedingOperators()) {
((Operator) oid.getOperator()).processAll(QueryResult
.createInstance(Arrays.asList(bind).iterator()), oid
.getId());
}
}
return null;
}
@Override
public String toString() {
final StringBuffer str = new StringBuffer("Iterator On")
.append("\n");
str.append(this.external.toString());
return str.toString();
}
@Override
public String toString(final Prefix prefixInstance) {
final StringBuffer str = new StringBuffer("Iterator On")
.append("\n");
str.append(this.external.toString(prefixInstance));
return str.toString();
}
@Override
public QueryResult join(final Indices indices, final Bindings bindings) {
return null;
}
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.process(null);
this.firstTime = false;
}
}
@Override
public void consumeDebug(final Triple triple, final DebugStep debugstep) {
if(this.firstTime){
this.startProcessingDebug(null, debugstep);
this.firstTime = false;
}
}
@Override
public boolean joinOrderToBeOptimized(){
return false;
}
}