SPI 3 Refactoring

[chrisdutz]

In this refactoring, we are replacing the existing Netty-based core into a set of lightweight sub-modules without requiring Netty at all and with as little third party dependencies as possible.

This will allow using our code-generation framework independently from building PLC4J drivers and allow porting PLC4X to other languages as we no longer rely on external libraries for which counterparts need to be integrated for new languages.

[sruehl]

really like the new syntax... :)

[sruehl]

wow awesome work @chrisdutz. Going through the changes, CoPilot also found some interessting things, but one thing that jumped to my eye was the use of the package name functions. I would propose to name it operations to not confuse it with functions used in programming.

[chrisdutz]

I just took the liberty to run the manual test benchmark in both the old and the new driver:

Old driver:

=== Test Summary ===
Single Item:
  Average Read Time:  13,80 ms (15 requests, 207 ms total)
  Average Write Time: 12,00 ms (15 requests, 180 ms total)
  Average Time:       12,90 ms
Multi Item (each 15 items):
  Average Read Time:  11,81 ms (100 requests, 1181 ms total)
  Average Write Time: 175,98 ms (100 requests, 17598 ms total)
  Average Time:       93,90 ms
======================
Test executed in 21570ms

New driver:

=== Test Summary ===
Protocol:  Modbus TCP (modbus-tcp)
Transport: TCP (tcp)
Single Item:
  Average Read Time:  14,60 ms (15 requests, 219 ms total)
  Average Write Time: 11,53 ms (15 requests, 173 ms total)
  Average Time:       13,07 ms
#Multi Item (each 15 items):
  Average Read Time:  16,47 ms (100 requests, 1647 ms total)
  Average Write Time: 174,59 ms (100 requests, 17459 ms total)
  Average Time:       95,53 ms
======================
Test executed in 19863ms

The new connection handling is quite a bit faster than the old Netty version. However, I see the new driver is in average 1ms/request slower ... will look into what I could do in order to improve that.

[chrisdutz]

Ok ... after the last commit, the new driver performs even a bit better than the old one:

=== Test Summary ===
Protocol:  Modbus TCP (modbus-tcp)
Transport: TCP (tcp)
Single Item:
  Average Read Time:  13,20 ms (15 requests, 198 ms total)
  Average Write Time: 11,80 ms (15 requests, 177 ms total)
  Average Time:       12,50 ms
#Multi Item (each 15 items):
  Average Read Time:  11,73 ms (100 requests, 1173 ms total)
  Average Write Time: 176,12 ms (100 requests, 17612 ms total)
  Average Time:       93,93 ms
======================
Test executed in 19532ms