public PercolateSourceBuilder addSort(SortBuilder sort){
  if (sorts == null) {
    sorts=new ArrayList<>();
  }
  sorts.add(sort);
  return this;
}

public PercolateSourceBuilder addSort ( SortBuilder sort ) { if ( sorts == null ) { sorts = new ArrayList < > ( ) ; } sorts . add ( sort ) ; return this ; }
adds a sort builder . only sorting by score desc is supported . by default the matching percolator queries are returned in an undefined order .
