Set < String > function ( ) { return headMap . keySet ( ) ; }
returns the set of headers used to tag this group concode_field_sep Map<String,Object> headMap concode_elem_sep List<T> list concode_elem_sep Object key concode_field_sep String getHeadValue concode_elem_sep int getSize concode_elem_sep List<Group<T>> subgroups concode_elem_sep List<T> find concode_elem_sep List<T> find concode_elem_sep Group<T> findGroup concode_elem_sep Group<T> findGroup concode_elem_sep List<T> findAll concode_elem_sep boolean isLeaf concode_elem_sep Set<String> keySet concode_elem_sep Object key concode_elem_sep T first