/// <summary>
/// Expert: low-level implementation method
/// Returns an <see cref="Explanation"/> that describes how <paramref name="doc"/> scored against
/// <paramref name="weight"/>.
///
/// <para/>This is intended to be used in developing <see cref="Similarities.Similarity"/> implementations,
/// and, for good performance, should not be displayed with every hit.
/// Computing an explanation is as expensive as executing the query over the
/// entire index.
/// <para/>Applications should call <see cref="IndexSearcher.Explain(Query, int)"/>. </summary>
/// <exception cref="BooleanQuery.TooManyClausesException"> If a query would exceed
/// <see cref="BooleanQuery.MaxClauseCount"/> clauses. </exception>
protected virtual Explanation Explain(Weight weight, int doc)
{
int n = ReaderUtil.SubIndex(doc, m_leafContexts);
AtomicReaderContext ctx = m_leafContexts[n];
int deBasedDoc = doc - ctx.DocBase;
return(weight.Explain(ctx, deBasedDoc));
}
public override Explanation Explain(AtomicReaderContext ir, int i)
{
Explanation inner = weight.Explain(ir, i);
Filter f = outerInstance.filter;
DocIdSet docIdSet = f.GetDocIdSet(ir, ir.AtomicReader.LiveDocs);
DocIdSetIterator docIdSetIterator = docIdSet == null?DocIdSetIterator.GetEmpty() : docIdSet.GetIterator();
if (docIdSetIterator == null)
{
docIdSetIterator = DocIdSetIterator.GetEmpty();
}
if (docIdSetIterator.Advance(i) == i)
{
return(inner);
}
else
{
Explanation result = new Explanation(0.0f, "failure to match filter: " + f.ToString());
result.AddDetail(inner);
return(result);
}
}
