@Override
public DocIdSet getDocIdSet(AtomicReaderContext context,
Bits acceptDocs) throws IOException {
final boolean nullBitset = random().nextInt(10) == 5;
final AtomicReader reader = context.reader();
DocsEnum termDocsEnum = reader.termDocsEnum(new Term("field", "0"));
if (termDocsEnum == null) {
return null; // no docs -- return null
}
final BitSet bitSet = new BitSet(reader.maxDoc());
int d;