[Geotools-gt2-users] GTXML / JAXB / GML parsing quest

[Akos M. <ak...@ma...>]

Hi,

I'm trying to continue on my quest to have GeoTools process AIXM 
documents, and as suggested earlier, I'm looking at the OWS package for 
inspiration. I saw that the OWS package has an EMF-generated class 
hierarchy, and basically it's turning XML ements into these 
EMF-generated classes. I figured an approach would be to do something 
similar with my JAXB generated class hierarchy, as I already have JAXB 
bindings set up. But I ran into practical & conceptual issues, see below.


I'm starting with a simple sample document that describes a single 
airspace, which is in effect a GML PolygonPatch with some metadata attached:

https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/var/test.aixm


for all the XML Schemas I already have JAXB code generation set up, this 
is the binding file: 
https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/resources/binding.xjb
although the generated classes are not checked in to the repository

I tried to create initial / minimal versions of GTXML parser 
configurations & bindings here:

https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/java/org/openaviationmap/aixm/AixmMessageParserConfiguration.java

https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/java/org/openaviationmap/aixm/AIXMMessage.java

https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/java/org/openaviationmap/aixm/bindings/AIXMBasicMessageBinding.java


and I have a very simple unit test for this here:

https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/test/java/org/openaviationmap/aixm/AIXMMessageParserTest.java


now, I encountered a number of conceptual problems that I'm not sure how 
to solve, and I'd really appreciate pointers & help:

- addding org.geotools.gm3.v3_2.GMLConfiguration as a depedency to my 
parser configuration doesn't make the GTXML parser parse GML data

for example, the first child of the root node in the test document 
contains a gml:boundedBy (gml:BoundingShapeType) construct, as 
documented here: 
http://www.sisostds.org/FEATProgrammersReference/feature_xsd.html - but 
even if I added the above GMLConfiguration as an addDependency() call to 
my configurations constructor (here, line 25: 
https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/java/org/openaviationmap/aixm/AixmMessageParserConfiguration.java#25 
) it seems that this is not parsed my the GTXML parser, and I get a 
simple NodeImpl instance for it in AIXMBasicMessageBinding.parse().


- package mismatch between JAXB-generated and geotools GML constructs

geotools has a org.geotools.xml.gml.GMLComplexTypes.BoundingShapeType 
class, while of course JAXB also generates a class by this name for the 
GML schema. moreover, if my aim is to return the JAXB-generated classes 
from my bindings parse() function, of course it would only accept the 
object related to it, that is, the JAXB-generated object. (see line 81 
here: 
https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/java/org/openaviationmap/aixm/bindings/AIXMBasicMessageBinding.java#81 
)

does this mean that basically it's not possible to work with the 
JAXB-generated class structure?


- if JAXB can already parse the whole file, what is the point of 
re-creating the parsing process?

from a conceptual perspective, I'm kind of lost here with creating / 
generating binding classes that extend AbstractComplexBinding, and 
basically duplicating the JAXB parsing functionality in each of these 
classes parse() function, just to come up with the same object hierarchy 
JAXB's unmarshaller can already create with two lines of code. this 
seems to be a useless exercise.


as you can see, I'm lost again, and maybe I'm asking totally irrelevant 
or obvious questions. I feel a little bit like Leisure Suite Larry in 
the Land of Lounge Lizards :)


Akos

<https://code.google.com/p/openaviationmap/source/browse/branches/oam-java-tools/aixm-datastore/src/main/resources/binding.xjb>