[jModbus-devel] Codebase Merge initial comments

[Kelvin P. <k.p...@st...>]

Dieter,

I'm still working through things but here are some of the initial comments
about how some of the code may need to be modified.  Overall however I
really like the look of things.

Cheers,

Kelvin

--- IO Package ---

The Modbus TCP Transport is not as fully robust as it might possibly be.
The only thing you
can really assume about a packet is that you can read 6 bytes to give the
complete header.
If that fails you close the socket.  You are not able to assume that you
will receive a unit
ID or a function code, which I do not believe should be part of the
transport.  The transport
should have the responsibility for framing and deframing a packet and should
not be concerned
with it's contents in any way.  I will modify this to behave like my
original package which
has all these protections and checks.

I'm also of the opinion that the interaction between the transport classes
and the message
classes should be done in terms of byte arrays.  (We should also user the
System.arrayCopy
function where required as it is implemented locally in a fast manner).
Where the rest
of the application desires streams based communications this should be done
through the use
ByteArray streams.  This would be done as it means that *only* the frame
data needs to be
transferred to the messaging classes, leaving all the other rubbish to do
with the differences
between the transport in the transport objects.  (Things like frame
delimnating breaks in the
RTU modes and CR LF and : breaks in the ASCII would stuff things up and the
whole situation
would not work for ASCII as the data is not binary encoded.)  I'll have a go
a modifying these
classes and we'll see what you think.

--- Process Image Package ---

I also like the way you have made all the registers etc.. interfaces as this
can provide a
means by which an event/listener interface as I has proposed can be avoided
completely.  If
you want to trigger on certain types of changes to a register values then
you implement the
register yourself so that so write the set command and get put whatever
trigger code in there
that you desire.