/// <summary>Returns the <see cref="FieldComparator" /> to use for
/// sorting.
///
/// <b>NOTE:</b> This API is experimental and might change in
/// incompatible ways in the next release.
///
/// </summary>
/// <param name="numHits">number of top hits the queue will store
/// </param>
/// <param name="sortPos">position of this SortField within <see cref="Sort" />
///. The comparator is primary if sortPos==0,
/// secondary if sortPos==1, etc. Some comparators can
/// optimize themselves when they are the primary sort.
/// </param>
/// <returns> <see cref="FieldComparator" /> to use when sorting
/// </returns>
public virtual FieldComparator GetComparator(int numHits, int sortPos)
{
if (locale != null)
{
// TODO: it'd be nice to allow FieldCache.getStringIndex
// to optionally accept a Locale so sorting could then use
// the faster StringComparator impls
return(new FieldComparator.StringComparatorLocale(numHits, field, locale));
}
switch (type)
{
case SortField.SCORE:
return(new FieldComparator.RelevanceComparator(numHits));
case SortField.DOC:
return(new FieldComparator.DocComparator(numHits));
case SortField.INT:
return(new FieldComparator.IntComparator(numHits, field, parser));
case SortField.FLOAT:
return(new FieldComparator.FloatComparator(numHits, field, parser));
case SortField.LONG:
return(new FieldComparator.LongComparator(numHits, field, parser));
case SortField.DOUBLE:
return(new FieldComparator.DoubleComparator(numHits, field, parser));
case SortField.BYTE:
return(new FieldComparator.ByteComparator(numHits, field, parser));
case SortField.SHORT:
return(new FieldComparator.ShortComparator(numHits, field, parser));
case SortField.CUSTOM:
System.Diagnostics.Debug.Assert(comparatorSource != null);
return(comparatorSource.NewComparator(field, numHits, sortPos, reverse));
case SortField.STRING:
return(new FieldComparator.StringOrdValComparator(numHits, field, sortPos, reverse));
case SortField.STRING_VAL:
return(new FieldComparator.StringValComparator(numHits, field));
default:
throw new System.SystemException("Illegal sort type: " + type);
}
}
/// <summary>
/// Returns the <seealso cref="FieldComparator"/> to use for
/// sorting.
///
/// @lucene.experimental
/// </summary>
/// <param name="numHits"> number of top hits the queue will store </param>
/// <param name="sortPos"> position of this SortField within {@link
/// Sort}. The comparator is primary if sortPos==0,
/// secondary if sortPos==1, etc. Some comparators can
/// optimize themselves when they are the primary sort. </param>
/// <returns> <seealso cref="FieldComparator"/> to use when sorting </returns>
public virtual FieldComparator GetComparator(int numHits, int sortPos)
{
switch (type)
{
case Type_e.SCORE:
return(new FieldComparator.RelevanceComparator(numHits));
case Type_e.DOC:
return(new FieldComparator.DocComparator(numHits));
case Type_e.INT:
return(new FieldComparator.IntComparator(numHits, field, parser, (int?)missingValue));
case Type_e.FLOAT:
return(new FieldComparator.FloatComparator(numHits, field, parser, (float?)missingValue));
case Type_e.LONG:
return(new FieldComparator.LongComparator(numHits, field, parser, (long?)missingValue));
case Type_e.DOUBLE:
return(new FieldComparator.DoubleComparator(numHits, field, parser, (double?)missingValue));
case Type_e.BYTE:
return(new FieldComparator.ByteComparator(numHits, field, parser, (sbyte?)missingValue));
case Type_e.SHORT:
return(new FieldComparator.ShortComparator(numHits, field, parser, (short?)missingValue));
case Type_e.CUSTOM:
Debug.Assert(comparatorSource != null);
return(comparatorSource.NewComparator(field, numHits, sortPos, reverse));
case Type_e.STRING:
return(new FieldComparator.TermOrdValComparator(numHits, field, missingValue == STRING_LAST));
case Type_e.STRING_VAL:
// TODO: should we remove this? who really uses it?
return(new FieldComparator.TermValComparator(numHits, field));
case Type_e.REWRITEABLE:
throw new InvalidOperationException("SortField needs to be rewritten through Sort.rewrite(..) and SortField.rewrite(..)");
default:
throw new InvalidOperationException("Illegal sort type: " + type);
}
}