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Thanks Martin,<br>
Indeed i didn't think in possible collision between real property
and attribute name. Now the explanations you provided are very
clear, and it's necessary to distinguish real properties vs.
attribute.<br>
Anyway on our side it's not blocking.<br>
<br>
I'm curious to know more about ongoing OGC discussions about API
& especially policy aspects. Is it possible to follow somewhere
the discussions?<br>
<br>
Thanks again<br>
Emmanuel<br>
<br>
<br>
<div class="moz-cite-prefix">Le 11/03/2015 18:04, Martin
Desruisseaux a écrit :<br>
</div>
<blockquote cite="mid:55007592.3060807@geomatys.com" type="cite">
<pre wrap="">Hello Emmanuel
Thanks for asking. I should have posted earlier what is going on.
We defined new Feature interfaces in GeoAPI [1][2], to be proposed to
OGC as GeoAPI 3.1 (date undetermined - OGC is starting a discussion
about what should be their policy about API). The new interfaces are
based on ISO 19109 and hopefully simpler. We are slowly starting
migration from the old to the new feature model.
One difference is that the old model was a little bit XML-oriented, and
distinguished between whether an information was a "XML attribute" or a
"XML value". The new model is more abstract and does not distinguish
such XML-specific details. We were thinking about applying a naming
convention but I'm not sure if this is done (Johann would know better).
An other issue is that we wanted to distinguish "real property" from
"generated property". The idea is to prefix "generated property" with
"@" to make them look like annotations. One goal was to avoid name
collision: maybe the feature has a real "fid" property which has nothing
to do with identifiers, so adding a "@" prefix for everything generated
would hopefully avoid collision (a little bit like the Java compiler
adding the "$" prefix in front of generated variable names).
The new ISO 19109 model has the concept of "operation", which we are
hopping to apply to the "@fid" attribute: if a real identifier already
exists in the feature, the "@fid" attribute would be an operation that
just delegate to the existing property. Otherwise the "@fid" attribute
would be an operation generating an identifier.
Do you think it would be okay?
Martin
[1] <a class="moz-txt-link-freetext" href="http://jira.codehaus.org/browse/GEO-229">http://jira.codehaus.org/browse/GEO-229</a>
[2]
<a class="moz-txt-link-freetext" href="http://www.geoapi.org/snapshot/javadoc/org/opengis/feature/package-summary.html">http://www.geoapi.org/snapshot/javadoc/org/opengis/feature/package-summary.html</a>
Le 11/03/15 16:40, Emmanuel Blondel a écrit :
</pre>
<blockquote type="cite">
<pre wrap="">I'm also wondering if it is correct to add this 'fid' as part of the
featureType by default, as it is not explicitely part of the WFS
DescribeFeatureType response (except maybe if we consider super
properties?)
Le 11/03/2015 16:10, Emmanuel Blondel a écrit :
</pre>
<blockquote type="cite">
<pre wrap="">Hello,
I'm using JAXPStreamFeatureReader and JAXBFeatureTypeReader to read
WFS data.
Until now everything worked well (WFS 1.0.0 / 1.1.0), now testing i
see i get the "fid" taken from the xml attribute of the same name.
Strangely the featureType retrieved prepends "fid" with "@" -> "@fid"
(i believe related code is
<a class="moz-txt-link-freetext" href="https://github.com/Geomatys/geotoolkit/blob/master/modules/jaxp-xml-parser/geotk-jaxp-gml/src/main/java/org/geotoolkit/feature/xml/jaxb/JAXBFeatureTypeReader.java#L748">https://github.com/Geomatys/geotoolkit/blob/master/modules/jaxp-xml-parser/geotk-jaxp-gml/src/main/java/org/geotoolkit/feature/xml/jaxb/JAXBFeatureTypeReader.java#L748</a>).
I'm just wondering if it's correct behavior.
It's good to have access to the feature identifier, but shouldn't we
rather expect to have the exact attribute name? (with no '@'). What
do you think? or is there a particular reason that requires this naming?
Thanks in advance
Bests,
Emmanuel
</pre>
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</blockquote>
<pre wrap="">
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<br>
<div class="moz-signature">-- <br>
<div style="color:#394377;">
<b>Emmanuel Blondel</b><br>
International Consultant | CEO <br>
<em>Geographic Information Systems in Agronomy, Environment,
Fishery & Marine Sciences</em><br>
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41, Avenue du Vacayrial<br>
81370 Saint Sulpice la Pointe, France<br>
Tel: +33 (0) 6 45 97 87 52<br>
Email: <a href="mailto:emmanuel.blondel1@gmail.com">emmanuel.blondel1@gmail.com</a><br>
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