package com.browseengine.bobo.facets.filter;
import java.io.IOException;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import com.browseengine.bobo.api.BoboIndexReader;
import com.browseengine.bobo.docidset.EmptyDocIdSet;
import com.browseengine.bobo.docidset.RandomAccessDocIdSet;
import com.browseengine.bobo.facets.FacetHandler;
import com.browseengine.bobo.facets.data.FacetDataCache;
import com.browseengine.bobo.util.BigSegmentedArray;
public class FacetFilter extends RandomAccessFilter
{
/**
*
*/
private static final long serialVersionUID = 1L;
private final FacetHandler<FacetDataCache> _facetHandler;
protected final String _value;
public FacetFilter(FacetHandler<FacetDataCache> facetHandler,String value)
{
_facetHandler = facetHandler;
_value=value;
}
public double getFacetSelectivity(BoboIndexReader reader)
{
double selectivity = 0;
FacetDataCache dataCache = _facetHandler.getFacetData(reader);
int idx = dataCache.valArray.indexOf(_value);
if(idx<0)
{
return 0.0;
}
int freq =dataCache.freqs[idx];
int total = reader.maxDoc();
selectivity = (double)freq/(double)total;
return selectivity;
}
public static class FacetDocIdSetIterator extends DocIdSetIterator
{
protected int _doc;
protected final int _index;
protected final int _maxID;
protected final BigSegmentedArray _orderArray;
public FacetDocIdSetIterator(FacetDataCache dataCache,int index)
{
_index=index;
_doc=Math.max(-1,dataCache.minIDs[_index]-1);
_maxID = dataCache.maxIDs[_index];
_orderArray = dataCache.orderArray;
}
@Override
final public int docID() {
return _doc;
}
@Override
public int nextDoc() throws IOException
{
return (_doc = (_doc < _maxID ? _orderArray.findValue(_index, (_doc + 1), _maxID) : NO_MORE_DOCS));
}
@Override
public int advance(int id) throws IOException
{
if (_doc < id)
{
return (_doc = (id <= _maxID ? _orderArray.findValue(_index, id, _maxID) : NO_MORE_DOCS));
}
return nextDoc();
}
}
@Override
public RandomAccessDocIdSet getRandomAccessDocIdSet(BoboIndexReader reader) throws IOException
{
FacetDataCache dataCache = _facetHandler.getFacetData(reader);
int index = dataCache.valArray.indexOf(_value);
if (index < 0)
{
return EmptyDocIdSet.getInstance();
}
else
{
return new FacetDataRandomAccessDocIdSet(dataCache, index);
}
}
private static class FacetDataRandomAccessDocIdSet extends RandomAccessDocIdSet{
private final FacetDataCache _dataCache;
private final BigSegmentedArray _orderArray;
private final int _index;
FacetDataRandomAccessDocIdSet(FacetDataCache dataCache,int index){
_dataCache = dataCache;
_orderArray = _dataCache.orderArray;
_index = index;
}
@Override
public boolean get(int docId) {
return _orderArray.get(docId) == _index;
}
@Override
public DocIdSetIterator iterator() throws IOException {
return new FacetDocIdSetIterator(_dataCache,_index);
}
}
}