// just return to make null snippet if un-matched fieldName specified when fieldMatch == true
if( termSet == null ) return;
for( String term : tpv.getTerms() ){
if( !termSet.contains( term ) ) continue;
int index = tpv.indexOf( term );
TermVectorOffsetInfo[] tvois = tpv.getOffsets( index );
if( tvois == null ) return; // just return to make null snippets
int[] poss = tpv.getTermPositions( index );
if( poss == null ) return; // just return to make null snippets
for( int i = 0; i < tvois.length; i++ )