/// <summary>Returns an explanation of the score for a document.
/// <br>When this method is used, the {@link #Next()} method
/// and the {@link #Score(HitCollector)} method should not be used.
/// </summary>
/// <param name="doc">The document number for the explanation.
/// </param>
/// <todo> Modify to make use of {@link TermDocs#SkipTo(int)}. </todo>
public override Explanation Explain(int doc)
{
TermQuery query = (TermQuery)weight.GetQuery();
Explanation tfExplanation = new Explanation();
int tf = 0;
while (pointer < pointerMax)
{
if (docs[pointer] == doc)
{
tf = freqs[pointer];
}
pointer++;
}
if (tf == 0)
{
while (termDocs.Next())
{
if (termDocs.Doc() == doc)
{
tf = termDocs.Freq();
}
}
}
termDocs.Close();
tfExplanation.SetValue(GetSimilarity().Tf(tf));
tfExplanation.SetDescription("tf(termFreq(" + query.GetTerm() + ")=" + tf + ")");
return(tfExplanation);
}