package com.browseengine.bobo.query;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Map;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Scorer;
import com.browseengine.bobo.api.BoboSegmentReader;
import com.browseengine.bobo.facets.FacetHandler;
import com.browseengine.bobo.query.scoring.BoboDocScorer;
import com.browseengine.bobo.query.scoring.FacetScoreable;
import com.browseengine.bobo.query.scoring.FacetTermScoringFunctionFactory;
import com.browseengine.bobo.query.scoring.MultiplicativeFacetTermScoringFunctionFactory;
public class FacetBasedBoostScorerBuilder implements ScorerBuilder {
protected final Map<String, Map<String, Float>> _boostMaps;
protected final FacetTermScoringFunctionFactory _scoringFunctionFactory;
public FacetBasedBoostScorerBuilder(Map<String, Map<String, Float>> boostMaps) {
this(boostMaps, new MultiplicativeFacetTermScoringFunctionFactory());
}
protected FacetBasedBoostScorerBuilder(Map<String, Map<String, Float>> boostMaps,
FacetTermScoringFunctionFactory scoringFunctionFactory) {
_boostMaps = boostMaps;
_scoringFunctionFactory = scoringFunctionFactory;
}
@Override
public Scorer createScorer(Scorer innerScorer, AtomicReader reader, boolean scoreDocsInOrder,
boolean topScorer) throws IOException {
if (!(reader instanceof BoboSegmentReader)) throw new IllegalArgumentException(
"IndexReader is not BoboSegmentReader");
return new FacetBasedBoostingScorer((BoboSegmentReader) reader, innerScorer);
}
@Override
public Explanation explain(AtomicReader indexReader, int docid, Explanation innerExplaination)
throws IOException {
if (!(indexReader instanceof BoboSegmentReader)) throw new IllegalArgumentException(
"IndexReader is not BoboSegmentReader");
BoboSegmentReader reader = (BoboSegmentReader) indexReader;
Explanation exp = new Explanation();
exp.setDescription("FacetBasedBoost");
float boost = 1.0f;
for (Map.Entry<String, Map<String, Float>> boostEntry : _boostMaps.entrySet()) {
String facetName = boostEntry.getKey();
FacetHandler<?> handler = reader.getFacetHandler(facetName);
if (!(handler instanceof FacetScoreable)) throw new IllegalArgumentException(facetName
+ " does not implement FacetScoreable");
FacetScoreable facetScoreable = (FacetScoreable) handler;
BoboDocScorer scorer = facetScoreable.getDocScorer(reader, _scoringFunctionFactory,
boostEntry.getValue());
float facetBoost = scorer.score(docid);
Explanation facetExp = new Explanation();
facetExp.setDescription(facetName);
facetExp.setValue(facetBoost);
facetExp.addDetail(scorer.explain(docid));
boost *= facetBoost;
exp.addDetail(facetExp);
}
exp.setValue(boost);
exp.addDetail(innerExplaination);
return exp;
}
private class FacetBasedBoostingScorer extends Scorer {
private final Scorer _innerScorer;
private final BoboDocScorer[] _facetScorers;
private int _docid;
public FacetBasedBoostingScorer(BoboSegmentReader reader, Scorer innerScorer) {
super(innerScorer.getWeight());
_innerScorer = innerScorer;
ArrayList<BoboDocScorer> list = new ArrayList<BoboDocScorer>();
for (Map.Entry<String, Map<String, Float>> boostEntry : _boostMaps.entrySet()) {
String facetName = boostEntry.getKey();
FacetHandler<?> handler = reader.getFacetHandler(facetName);
if (!(handler instanceof FacetScoreable)) throw new IllegalArgumentException(facetName
+ " does not implement FacetScoreable");
FacetScoreable facetScoreable = (FacetScoreable) handler;
BoboDocScorer scorer = facetScoreable.getDocScorer(reader, _scoringFunctionFactory,
boostEntry.getValue());
if (scorer != null) list.add(scorer);
}
_facetScorers = list.toArray(new BoboDocScorer[list.size()]);
_docid = -1;
}
@Override
public float score() throws IOException {
float score = _innerScorer.score();
for (BoboDocScorer facetScorer : _facetScorers) {
float fscore = facetScorer.score(_docid);
if (fscore > 0.0) {
score *= fscore;
}
}
return score;
}
@Override
public int docID() {
return _docid;
}
@Override
public int nextDoc() throws IOException {
return (_docid = _innerScorer.nextDoc());
}
@Override
public int advance(int target) throws IOException {
return (_docid = _innerScorer.advance(target));
}
@Override
public int freq() throws IOException {
// TODO Auto-generated method stub
return 0;
}
@Override
public long cost() {
// TODO Auto-generated method stub
return 0;
}
}
}