[Step-imp] Re: Question to AP owners/implementors on XML Schema use
(Part 28 Edition 2)
Martin Hardwick
hardwick at steptools.com
Thu Jun 3 11:24:53 EDT 2004
Tom,
If by late binding you mean a binding written like the Part 21
binding but with XML tags defined for the entities, attributes
and external mappings, then I agree.
This will give us a file format that can be manipulated using
XML tools, checked for structural syntax conformance using XMLSchema,
and understood/implemented by the average technical person.
A simple language is attractive to us for the AP-238 project because
we have found a way to support views of the data using modules based
on the STEP-NC ARM. The methodology relies on extracting information from
the mapping tables and using it to encapsulate the AIM entities. The
wrapping explains how the AIM entities represent an ARM object so it is
no longer necessary to manipulate the AIM entities into a logical
representation using the configuration language.
As I see it the following issues have led to undesirable complexity in P28 e2.
1. Using EXPRESS to define XMLSchema that defines the data. This is a meta-meta
data approach, instead it would be better to follow the P21 model.
2. Overly aggressive efforts to force the semantics of EXPRESS into XMLSchema,
in particular the inheritance model, again it would be better to follow
the P21 model.
3. The need to support a legacy (another reason for the configuration
language).
Martin
At 11:01 AM 6/2/2004 -0500, trthurma at rockwellcollins.com wrote:
>All,
>As a result of an evaluation of some experiments with Part 28 ed 2
>compiler kindly executed by Electric Boat,
>the AP 210 project has a concern with the lack of support in the standard
>for the so-called "late binding" approach.
>
>Best Regards,
>Tom Thurman
>
>(My apologies to those who have already seen this message.)
>
>Thomas R. "Tom" Thurman
>MS 106-183
>Rockwell Collins Inc.
>400 Collins Road N.E.
>Cedar Rapids Ia, 52498, USA
>phone:(319)295-2280
>FAX:(319)295-0654
>This email and any attachments are confidential to the intended recipient
>and may also be privileged. If you are not the intended recipient please
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>
>
>
> Martin Hardwick
> <hardwick at steptoo To: "David Price" <david.price at eurostep.com>, <wg3 at tc184-sc4.org>,
> ls.com> <wg12 at tc184-sc4.org>
> cc: <expressIF at tc184-sc4.org>, <step-imp at steptools.com>,
> 12/02/2003 02:26 step-manufacturing at steptools.com, xmlsc4 at nist.gov
> PM Subject: Re: Question to AP owners/implementors on XML Schema use (Part 28 Edition
> 2)
>
>
>
>
>
>
>
>All,
>
>In response to David's request below here is a STEP-Manufacturing
>perspective:
>
>1. The STEP Manufacturing AP's (AP-219, AP-224, AP-238 and AP-240)
> are already highly inter-operable using P21 technology. High
> level API's have already been written for these AP's.
>
>2. The STEP Manufacturing data is intricate and highly complex. The
> weakness of the existing P21 technology is that the data is hard
> to read and copy so the form of the XML document is MOST IMPORTANT.
>
>3. If a single configuration for all AP's can satisfy the whole
> community then this is better than multiple configurations. However
> the experience of P28 Edition 1 suggests that readable data will
> only be produced if each AP has its own configuration.
>
>4. Much information required to define a configuration is already
> in the mapping tables. The manufacturing AP's are harmonized by
> using the same mappings for the same concept. Therefore, they will
> continue to be inter-operable.
>
>
>Martin Hardwick
>Team Leader Wg3/T24 STEP-Manufacturing
>
>At 04:39 PM 12/2/2003 +0000, David Price wrote:
>
>>Hello WG3 and WG12,
>>
>>
>>
>>We ve been working with the AP233 and AP239 teams on Part 28 Edition 2 and
>XML Schema. Part 28 E2 introduces a configuration language allowing the
>production of an XML schema to be tailored for an EXPRESS schema. The
>tailoring can happen at the global, entity and/or attribute level. The
>issue that has been raised during the discussions with AP233 and AP239 is
>if, or how, this capability should be used.
>>
>>
>>
>>I m trying to gather business requirements and technical requirements in
>this area. If you have requirements or usage scenarios in this area, I d
>appreciate hearing about them.
>>
>>
>>
>>So far, what I ve heard from these two teams (and relayed to the Part 28
>team today) is the following:
>>
>>
>>
>>1) A single configuration to produce a default data exchange XML Schema
>for both (or all?) APs is required. Some have said they want WG3/SC4 to
>agree and mandate a single configuration for AP implementation.
>>
>>2) Exactly what the XML document looks like is not that important as a
>high level, model based API will be used.
>>
>>3) The XML schema elements should be recognizable as being derived from
>the EXPRESS schema, but trying to reflect the EXPRESS structure in XML is
>less important than simplicity and consistency.
>>
>>4) Interoperability, and therefore the same configuration, is a high
>priority for AP233, AP239 and PDM capabilities.
>>
>>5) The first AP233 and AP239 implementations will be based on the ARM, not
>the AIM. This may continue to be true for all implementations as well.
>>
>>6) The PLCS consortium is planning on publishing the AP239 ARM XML Schema
>through OASIS, so they don t expect implementations to be EXPRESS-based.
>>
>>
>>
>>Do other AP teams share these requirements? I agree they are not all
>completely consistent (ARM v. AIM), but requirements seldom are. If your
>requirements are different, in what way?
>>
>>
>>
>>Cheers,
>>
>>David
>>
>>
>>
>>Phone +44 20 7704 0499
>>
>>Mobile +44 7788 561308
>>
>>8 Highbury Place, Flat 5
>>
>>London N5 1QZ
>>
>>
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