The original NioFlex API, while relatively abstract and powerful, was also somewhat narrow. The original goal was to allow for the creation of nonblocking TCP servers -- and that was it. However, it would be more useful to broaden this goal to make the framework more useful.
Specifically, the new goal is to extend NioFlex to allow for the creation of different kinds of scalable servers. However, this requires a substantial rewrite to the API to accommodate these planned changes.
In NioFlex, the SocketUtil class contains a set of methods that make interfacing
with raw Java NIO a lot easier.
It is mandatory that you use this API to perform NIO operations because of how the server is designed, but don't worry, the API is extremely easy to learn.
NioFlex is a powerful tool that you need to fully understand to be able to take advantage of all of its features. It is recommended that you have a grasp of Java NIO, since NioFlex is built on top of it.
The current 'dev' release of NioFlex is 0.20-rc1 and it contains many important improvements over the stable 0.10.
It is recommended that you learn from this 'dev' build and not the stable 0.10 because of the numerous differences between the two.