validDocs=new BitSet(reader.maxDoc());
// set merger for type terms
Vector<PwaSearchable> vecTermsAux=new Vector<PwaSearchable>();
for (int i=0;i<types.length;i++) {
vecTermsAux.add(new PwaExtraTerm(new Term(fieldName,types[i]),reader));
}
PwaMerger merger=new PwaMerger(vecTermsAux, false);
while (merger.next()) {
validDocs.set(merger.doc(), true);