separate general complex feature classes from gt app schema

• Contact: Niels Charlier

• Tracker: GEOT-4344

Description

The idea is to split the app-schema module in three:

• The first part would contain everything that helps with complex features in general and can be moved to gt-main: mainly builders
• The second part would contain everything that helps with complex features in general and depends on XSD: evaluating filters against them (property accessor, x-path evaluation), building complex feature types from XSD. These classes do not rely on specific schemes like GML, etc... apart form XS.
• The third part will contain anything that is app-schema specific: creating complex feature datastores with mapping files.

The third part would continue as the gt-app-schema module. The first part will be moved to gt-main. More specifically, the following classes will be moved:

• org.geotools.feature.TypeBuilder
• org.geotools.util.ComplexAttributeConverterFactory
• org.geotools.feature.AttributeBuilder (PARTLY)
• org.geotools.feature.Types (PARTLY)

The second would split off and become a new module 'gt-complex'. More specifically, this 'gt-complex' module will consist of the following classes that are now in the gt-app-schema module.

• org.geotools.filter.expression.FeatureProperty + complete org.geotools.feature.xpath package
• complete org.geotools.feature.type package
• org.geotools.data.complex.filter.XPath (PARTLY)
• org.geotools.data.complex.FeatureTypeRegistry (PARTLY) + depending classes (for building types from xsd)
• org.geotools.data.complex.config.EmfAppSchemaReader

Considering the 'partly' ported classes.

• AttributeBuilder - will still need an extended version in app-schema to support the NonFeatureTypeProxy which uses mappings
• XPath , Types - are just classes of different static methods that need to be split in two
• FeatureTypeRegistry will be made more generic using a helper interface 'FeatureTypeRegistryHelper, app-schema can have its specific implementation

The gt-complex module will have a dependency on the module gt-app-schema-resolver.

Status

This proposal is currently being voted on:

• Andrea Aime +1
• Ben Caradoc-Davies +1
• Christian Mueller
• Ian Turton +1
• Justin Deoliveira
• Jody Garnett
• Simone Giannecchini

Tasks

This section is used to make sure your proposal is complete (did you remember documentation?) and has enough paid or volunteer time lined up to be a success

1. ✅ NC: move/copy all the classes (specified above) into new module 'gt-complex'

2. ✅ NC: refactor app-schema to use the gt-complex module and the new featuretyperegistry

3. ✅ NC: Pull request for GEOT-4344 \

   • https://github.com/geotools/geotools/pull/88 complex model refactoring

4. NC: review the geotools documentation and update

   • upgrade instructions for 9.x will need to mention this new dependency

API Changes

The API will not change because of this.

Documentation Changes

gt-complex should get its own page in the GeoTools User Documentation. ** The application-schema documentation page says "Key to the configuration of the app-schema module is the mapping file". The gt-complex module provides support for complex features but has nothing to do with mapping files.

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