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Re: Design pattern: refresh-based or event-based?

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pozz <pozzugno@gmail.com> writes:
> As I wrote in another post, one thing is the events triggered by the
> graphical toolikt (even emwin is event-based) and another is the
> events generated by the applications, for example from the lower level
> layer that manages the field bus (remote sensors/peripherals)...
> Even in this scenario I can decide to update *values* on the display
> at a regular time base, for example every 100ms. 

Yes, it's just not clear to me why to do that.

Do you know the idea of Model-View-Controller (MVC)?  It might be
helpful here:

  https://en.wikipedia.org/wiki/Model-view-controller

Basically it means you have a data object (the model) tracking the state
of the system.  The "controller" reads stuff from the field bus and
updates values in the model, and then the display (the view) shows the
contents of the model.

It's generally reasonable for the controller posting updates to values
in the model to also send events to the UI as the updates happen.  In a
simple system the model can be the state of the UI widgets.  UI
libraries will typically let you read from the widgets as well as write
to them.

You do end up wanting to use some concurrency in these interfaces, but
if you implement it with message passing and accept a bit of overhead
from that, you're reasonably safe from the classic hazards of concurrent
programming.

What hardware and OS are you using?  

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Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-21 10:02 +0200
  Re: Design pattern: refresh-based or event-based? upsidedown@downunder.com - 2015-07-21 11:37 +0300
    Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-21 11:00 +0200
      Re: Design pattern: refresh-based or event-based? Dimiter_Popoff <dp@tgi-sci.com> - 2015-07-22 01:34 +0300
        Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 06:57 +0200
          Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-21 23:02 -0700
            Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 09:17 +0200
              Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-22 00:23 -0700
        Re: Design pattern: refresh-based or event-based? upsidedown@downunder.com - 2015-07-22 10:02 +0300
          Re: Design pattern: refresh-based or event-based? Dimiter_Popoff <dp@tgi-sci.com> - 2015-07-22 19:48 +0300
            Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-23 09:04 +0200
              Re: Design pattern: refresh-based or event-based? Dimiter_Popoff <dp@tgi-sci.com> - 2015-07-23 10:29 +0300
                Re: Design pattern: refresh-based or event-based? raimond.dragomir@gmail.com - 2015-07-31 02:34 -0700
  Re: Design pattern: refresh-based or event-based? Don Y <this@is.not.me.com> - 2015-07-21 03:16 -0700
  Re: Design pattern: refresh-based or event-based? Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2015-07-21 14:40 +0200
    Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 07:01 +0200
      Re: Design pattern: refresh-based or event-based? Stefan Reuther <stefan.news@arcor.de> - 2015-07-22 18:30 +0200
        Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-22 10:55 -0700
  Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-21 08:26 -0700
    Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 07:04 +0200
      Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-21 23:13 -0700
        Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 09:24 +0200
          Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-22 08:26 -0700
            Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-23 09:00 +0200
  Re: Design pattern: refresh-based or event-based? hamilton <hamilton@nothere.com> - 2015-07-21 14:07 -0600
    Re: Design pattern: refresh-based or event-based? Don Y <this@is.not.me.com> - 2015-07-21 13:12 -0700
  Re: Design pattern: refresh-based or event-based? Andrew Smallshaw <andrews@sdf.lonestar.org> - 2015-07-22 00:19 +0000
    Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-21 18:09 -0700
      Re: Design pattern: refresh-based or event-based? Andrew Smallshaw <andrews@sdf.lonestar.org> - 2015-07-22 21:18 +0000
        Re: Design pattern: refresh-based or event-based? Paul Rubin <no.email@nospam.invalid> - 2015-07-22 23:17 -0700
    Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 07:20 +0200
    Re: Design pattern: refresh-based or event-based? upsidedown@downunder.com - 2015-07-22 10:53 +0300
  Re: Design pattern: refresh-based or event-based? pozz <pozzugno@gmail.com> - 2015-07-22 07:32 +0200

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