public void addFeature(FeatureVectorBuffer fvb){
  idxList.addAll(fvb.idxList);
  valList.addAll(fvb.valList);
}

public void addFeature ( FeatureVectorBuffer fvb ) { idxList . addAll ( fvb . idxList ) ; valList . addAll ( fvb . valList ) ; }
currentvector = currentvector + fvb
