private <T> T onMap(Function<RMap<String, String>, T> func) {
        final RMap<String, String> map = client.getMap(prefix);
        return func.apply(map);
    }
private < T > T onMap ( Function < RMap < String , String > , T > func ) { final RMap < String , String > map = client . getMap ( prefix ) ; return func . apply ( map ) ; }
Pass an {@link RMap} to the function and return its result.

@param func the function to apply using the {@link RMap}
@return the result