public override Query Rewrite(IndexReader reader, MultiTermQuery query)
{
FilteredTermEnum enumerator = query.GetEnum(reader);
BooleanQuery result = new BooleanQuery(true);
int count = 0;
try
{
do
{
Term t = enumerator.Term;
if (t != null)
{
TermQuery tq = new TermQuery(t); // found a match
tq.Boost = query.Boost * enumerator.Difference(); // set the boost
result.Add(tq, Occur.SHOULD); // add to query
count++;
}
}while (enumerator.Next());
}
finally
{
enumerator.Close();
}
query.IncTotalNumberOfTerms(count);
return(result);
}
public override Query Rewrite(IndexReader reader, MultiTermQuery query)
{
// Get the enum and start visiting terms. If we
// exhaust the enum before hitting either of the
// cutoffs, we use ConstantBooleanQueryRewrite; else,
// ConstantFilterRewrite:
ICollection <Term> pendingTerms = new List <Term>();
int docCountCutoff = (int)((docCountPercent / 100.0) * reader.MaxDoc);
int termCountLimit = System.Math.Min(BooleanQuery.MaxClauseCount, termCountCutoff);
int docVisitCount = 0;
FilteredTermEnum enumerator = query.GetEnum(reader);
try
{
while (true)
{
Term t = enumerator.Term;
if (t != null)
{
pendingTerms.Add(t);
// Loading the TermInfo from the terms dict here
// should not be costly, because 1) the
// query/filter will load the TermInfo when it
// runs, and 2) the terms dict has a cache:
docVisitCount += reader.DocFreq(t);
}
if (pendingTerms.Count >= termCountLimit || docVisitCount >= docCountCutoff)
{
// Too many terms -- make a filter.
Query result = new ConstantScoreQuery(new MultiTermQueryWrapperFilter <MultiTermQuery>(query));
result.Boost = query.Boost;
return(result);
}
else if (!enumerator.Next())
{
// Enumeration is done, and we hit a small
// enough number of terms & docs -- just make a
// BooleanQuery, now
BooleanQuery bq = new BooleanQuery(true);
foreach (Term term in pendingTerms)
{
TermQuery tq = new TermQuery(term);
bq.Add(tq, Occur.SHOULD);
}
// Strip scores
Query result = new ConstantScoreQuery(new QueryWrapperFilter(bq));
result.Boost = query.Boost;
query.IncTotalNumberOfTerms(pendingTerms.Count);
return(result);
}
}
}
finally
{
enumerator.Close();
}
}
public override Query Rewrite(IndexReader reader)
{
if (!termLongEnough)
{
// can only match if it's exact
return(new TermQuery(Term));
}
int maxSize = BooleanQuery.MaxClauseCount;
// TODO: Java uses a PriorityQueue. Using Linq, we can emulate it,
// however it's considerable slower than the java counterpart.
// this should be a temporary thing, fixed before release
SortedList <ScoreTerm, ScoreTerm> stQueue = new SortedList <ScoreTerm, ScoreTerm>();
FilteredTermEnum enumerator = GetEnum(reader);
try
{
ScoreTerm st = new ScoreTerm();
do
{
Term t = enumerator.Term;
if (t == null)
{
break;
}
float score = enumerator.Difference();
//ignore uncompetetive hits
if (stQueue.Count >= maxSize && score <= stQueue.Keys.First().score)
{
continue;
}
// add new entry in PQ
st.term = t;
st.score = score;
stQueue.Add(st, st);
// possibly drop entries from queue
if (stQueue.Count > maxSize)
{
st = stQueue.Keys.First();
stQueue.Remove(st);
}
else
{
st = new ScoreTerm();
}
}while (enumerator.Next());
}
finally
{
enumerator.Close();
}
BooleanQuery query = new BooleanQuery(true);
foreach (ScoreTerm st in stQueue.Keys)
{
TermQuery tq = new TermQuery(st.term); // found a match
tq.Boost = Boost * st.score; // set the boost
query.Add(tq, Occur.SHOULD); // add to query
}
return(query);
}
