Read<T> + perform(graph : ReadGraph) : T AsyncRead<T> + perform(graph : AsyncReadGraph, procedure : AsyncProcedure<T>) AsyncMultiRead<T> + perform(graph : AsyncReadGraph, callback : AsyncMultiProcedure<T>) PrimitiveRead<T> + register(procedure : Listener<T>) Write +perform(graph : WriteGraph) ... WriteOnly + void perform(graph : WriteOnlyGraph) MultiRead<T> + perform(graph : ReadGraph, callback : AsyncMultiProcedure<T>)