RE: XML to 5250 -- MIDRANGE-L

Hi Jon,

what about trying some different wording?  you want to render xml onto a
5250 display device!  What does the xml in the xml to 5250 equation add? Can
what is being asked be expressed as "html to 5250"? Html can be rendered to
a 5250 dsply to a degree, but the positioning and dsply space needed for
tables, especially nested tables would call for quite a bit of streamlining
of the output.

A hard part of html to 5250 display is getting the data entry, screen
navigation commands back to the application ( the one that wrote out the xml
stream and that is presumably reentrant and reads posted environment
variables to receive what the browser has sent ).  The 5250 device driver
pgm/job would have to "post" the disply input to html formatted response
data stream.  After posting the response like a browser does, it has to then
wait for the next stream of xml/html to be sent down to it.

So the 5250 interactive display, the xml to 5250 job, does the following:
  a. user signs on, hits the command key saying they are
     ready for some xml
  b. send some sort of a cmd up to the base appl server saying
     that a dsply is ready for its first html document.
  c. interactive job waits on dtaq for the xml/html "to-display"
     data stream ( during this time the screen is blank )
  d. xml/html data stream is received and rendered as best as
     possible to the display.
  e. user makes an entry, presses enter
  f. the interactive pgm composes the "response to base appl" data
     stream in "html posted data" form and sends to the data queue
     back to the base appl.
  g. loop back to step c.

another problem with all of this is interfacing with the host appl server
complex.  That is the http server that is routing the xml down to the mix of
display station browsers and up to the cgi like instances that constitute
the "base appl". That alone, if I am reading you right Jon, might be a show
stopper.

Does the apache server have such an interface?

Steve Richter

-----Original Message-----
From: midrange-l-bounces@midrange.com
[mailto:midrange-l-bounces@midrange.com]On Behalf Of Jon Paris
Sent: Tuesday, February 11, 2003 3:54 PM
To: Midrange-L
Subject: XML to 5250


OK - I'm going to try this topic again and this time I have the time to
explain a little more fully what I'm looking for and why.

First I understand _what_ XML is and isn't - I understand that I need a DTD
or schema to define the form of the XML etc. etc. so let's not get into that
again.

What I am trying to do is to build a new app with completely separated UI
logic.  The same base app will be used for multiple customers.  The overall
application flow and the data passing back and forward to the UI is
(relatively) stable from customer to customer _but_ some customers will want
to see the output on a browser, some on a 5250, etc.  Not only that - but
the browser customers will all want different formats.  So will the 5250
users - each one wants the data to look the way they want it.

So - it seemed to me that defining the data in XML and using XSL to do the
browser transforms was a reasonable approach to this.  What I wanted to do
was apply the same principals to the 5250 users.  Since using conventional
DDS based screens does not offer the required flexibility, the notion was to
generate the 5250 XSL (or some internal equivalent) by working with some
kind of design tool to determine where on the screen each piece of the data
should be displayed etc. etc.  The XML would then be transformed into 5250
datastream (and back) by the UI handler.

As noted in the original post - I thought someone already had this but I
can't find it and the links sent to me did not seem to offer this kind of
facility.

So - does this work?  If not - what is the alternative?

Jon Paris
Partner400


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