Re: Web Services Adapter for 5250 Applications

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Nathan Andelin wrote:
> Joe,
>
> Thanks for the explanation of adapters for 5250 applications.  You've 
> obviously put more thought and work into this than I, so I'll defer to 
> your expertise.
>   
Yeah, I've been doing this for a while.  The interesting thing is that 
no matter what you do in the web world - be it a new user interface, a 
client/server model or simply exposing your processes as services - you 
have to move from the 5250 screen-at-a-time paradigm to a message-based 
process-oriented model.  Once you understand that, you can then review 
your requirements and determine which is the best route to take.

> Regarding my comment about the Zend 5250 Bridge being unwieldy for 
> developing web services adapters, that was just my first impression, and 
> I should probably defer to Jon Paris or somebody from Zend, if they'd 
> like to jump in.  The thing that triggered my comment was the 
> understanding that the Webfacing server doesn't know display file "field 
> names", so the 5250 bridge generates names using sequential numbers 
> based on field positions on the screen.  If positions change sometime 
> down the road, the developer would need to change the names in his PHP 
> script.  It seemed like an iterative, investigation process.  Connect to 
> the screen.  Query the screen objects.  Mentally map generated names to 
> the names in the display file, and write code based on your 
> investigation.  And change your code when the screen changes.
>   
Yeah, that does sound ugly.  I can't imagine that's really how they 
designed it, unless they don't even examine the display file object and 
instead just work off the 5250 data stream.

Joe