Re: [ws-calendar] PIM progress and questions - 30 November 2012

[William Cox <wtcox@CoxSoftwareArchitects.com>]

Mike and all --

Comments interleaved.

My interest is in the attribute typing in the PIM UML model, so keep that in mind. Transformability from the PIM to the PSM (the first WS-Calendar example) and to something more like the second. 

In the PIM we will not have a large number of attributes, properties, etc -- that's characteristic of the WS-Calendar/xcal model, and is what makes the UML of ws-calendar pretty useless; it's at a lower level than the abstraction of interval, etc, and the minimal data types needed to represent "logical" (PIM) intervals.

To elaborate on a not-quite-coherent comment I made in the meeting today, the goal is to create a PIM that can be transformed a la MDA to WS-Calendar/xcal.  The broader purpose is to have a common abstract model (the PIM) that can be used to create new PSMs, such as those in Streams and those that others have discussed, that is, the "optimizations".

I want to reiterate that your comment on letting the data speak for itself, or moving knowledge into the program was very clear and elegant.  The knowledge "in the code that interprets" is the base of many of the "optimizations" that in turn "pessimize" some of the broader goals of interoperability.  I intend that the PIM provide a clean path so those applying the standards can make choices relevant to their tasks while still having a clean and clear path to interoperability.  And in enterprise/SOA contexts, XSLTs are the common means for realization.

Thanks!

bill
--

William Cox
Email: wtcox@CoxSoftwareArchitects.com
Web: http://www.CoxSoftwareArchitects.com
+1 862 485 3696 mobile
+1 908 277 3460 fax

On 11/30/12 12:04 PM, Mike Douglass wrote:

I think we get too tied up with the specifics of the XML for xCal.

xCal is designed to be as robust as possible in the face of changes to the spec. For example, it would not be surprising to have the value for a tzid be a url or a uri.

Any system which wants to implement a stripped down version of xcal - or any other representation - is free to do so. But I think to claim conformance they have to be able to handle issues of that kind. If internally to their system that always "know" that tzid is text they can handle it that way - but they'd better fail gracefully if one day they read some xcal with a URL for a tzid.

This is complicated by the fact that a URI can be treated as a string but you have to constrain going the other way (looking at the attribute types).

The last form looks like a multi-valued property.

With the goal of simplification, there are indeed multi-values, and there's no concept in UML of XML attributes versus elements; they're all "attributes" without the implication that they sort of attach to a container for a value.

So a "date-time with timezone" probably should be defined similarly to the third example, a class with two attributes, one string, one constrained string with the xcal:date-time constraints on it.

Here the interesting part recalls the XSD/iCal/xCal/ws-cal date-time semantics and what's expressible.

Fortunately, what the PIM needs to express is a VALUE and if you transform to a Platform Specific Model (PSM) that uses XML you can still express everything, and the "missing" parts get fixed in the translation.  Not ideal, but still useful IMO.

For each of these specializations you have to build into the application knowledge of the structure of the property (at the time you built your application).

That's fair enough if you're prepared to handle the changes that can occur to the data coming from other systems - but that might mean code changes.

I'd guess the answer is a qualified "yes"

Is that to the last two, or some combination of the last two? 

:-)

On 11/30/2012 11:50 AM, Considine, Toby (Campus Services IT) wrote:

I have been chewing on the many dates we have in WS-Calendar. These are of the format (in XML)

 

            <xcal:dtstart>

                        <xcal:parameters>

                                    <xcal:tzid>

                                                <xcal:text>America/New_York</xcal:text>

                                    </xcal:tzid>

                        </xcal:parameters>

                        <xcal:date-time>2011-05-28T08:45:00</xcal:date-time>

            </xcal:dtstart>

 

Can a specification that claims conformance, and does  not need to communicate with calendar servers,  look like:

 

            <xcal:dtstart>

                        <xcal:tzid>

                                    <xcal:text>America/New_York</xcal:text>

                        </xcal:tzid>

                        <xcal:date-time>2011-05-28T08:45:00</xcal:date-time>

            </xcal:dtstart>

 

Or even like

 

            <xcal:dtstart>

                        <xcal:tzid>America/New_York</xcal:tzid>

                        <xcal:date-time>2011-05-28T08:45:00</xcal:date-time>

            </xcal:dtstart>

 

 

tc

---

"Computers are useless. They can only give you answers."     -- Pablo Picasso 

---

Toby Considine Chair, OASIS oBIX TC Editor, OASIS EMIX, Energy Interoperation Campus Services Information Technology University of North Carolina Chapel Hill, NC

Email: Toby.Considine@ unc.edu Phone: (919)962-9073 http://www.oasis-open.org http://www.NewDaedalus.com

 

 

From: ws-calendar@lists.oasis-open.org [mailto:ws-calendar@lists.oasis-open.org] On Behalf Of William Cox
Sent: Friday, November 30, 2012 11:35 AM
To: ws-calendar@lists.oasis-open.org
Subject: [ws-calendar] PIM progress and questions - 30 November 2012

 

All --

For today's meeting.

I've been filling in the text for the sections (WD01 shows the model only).

On the PIM I have a number of questions to discuss at the meeting and/or on the email list. I'd appreciate your thoughts and comments on these points.

1. The target is the PIM, not MDA; see item 5 for an example mapping to WS-Calendar 1.0.
2. I've seen and heard no comments; since the document is not complete that's not surprising. I hope.
3. For conformance should the relevant parts of WS-Calendar 1.0 be copied with changes? Or referenced with changes?
4. Should the conformance target be the RFCs or WS-Calendar 1.0? I think the latter.
5. I believe that there should be a non-normative appendix (or perhaps a Committee Note) showing the map from the PIM to WS-Calendar 1.0.
6. Should there be other examples of PIM use and the broader MDA perspective? Non-normative, I think.

Thanks!

bill
--
William Cox
Email: wtcox@CoxSoftwareArchitects.com
Web: http://www.CoxSoftwareArchitects.com
+1 862 485 3696 mobile
+1 908 277 3460 fax

On 11/30/12 7:14 AM, Gershon Janssen wrote:

Web Services Calendar (WS-Calendar) TC

30 November 2012, 12:00pm ET, 06:00pm CET

 

Call-In Information:

 

Australia: +61 (0) 7 3123 6030

Austria: +43 (0) 7 20881407

Belgium: +32 (0) 28 08 4297

Canada: +1-778-785-0724

Denmark: +45 69 91 88 70

Finland: +358 942 599 697

France: +33 (0) 182 880 463

Germany: +49 (0) 898 7806 6464

Ireland: +353 (0) 14 845 983

Italy: +39 0553989569

Netherlands: +31 (0) 208 080 385

New Zealand: +64 (0) 4 974 7216

Norway: +47 21 04 29 13

Spain: +34 955329911

Sweden: +46 (0) 313 613 559

Switzerland: +41 (0) 225 3314 55

United Kingdom: +44 (0) 203 318 4725

United States: +1-626-521-0010

 

Access Code: 114-622-898

 

No need for an audio PIN

 

Thanks to LONMARK for the conference call support.

 

Chat: http://webconf.soaphub.org/conf/room/ws-calendar

 

 

DEFAULT AGENDA

 

0. Roll call, Agenda review

 

1. Approval of minutes

 

* 09 November 2012 meeting minutes:

https://www.oasis-open.org/committees/document.php?document_id=47425&wg_abbrev=ws-calendar

 

2. FYI / announcements from Chair, Secretary, Liaison

 

3. Discussion

 

* December meeting schedule

 

* Review of PIM work

URL to full PIM wd01 package (docx, pdf, XMI, and EAP): https://www.oasis-open.org/committees/document.php?document_id=47502&wg_abbrev=ws-calendar

 

* Possible other items:

 

- Conformance in REST

 

-  Streams

Initial release of Streams, including the HTML, DOC, PDF, and Schema.

URL: https://www.oasis-open.org/committees/document.php?document_id=47420&wg_abbrev=ws-calendar

 

4. Any Other Business?

 

5. Adjourn

 

---

 

Regards,

 

Gershon Janssen

 

---

Spam
Not spam
Forget previous vote

-- 

Mike Douglass                           douglm@rpi.edu
Senior Systems Programmer
Communication & Collaboration Technologies      518 276 6780(voice) 2809
(fax)
Rensselaer Polytechnic Institute 110 8th Street, Troy, NY 12180