GeoTools : Separate general complex feature classes from gt-app-schema


Niels Charlier







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
  • (PARTLY)
  • (PARTLY) + depending classes (for building types from xsd)

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.


This proposal is currently being voted on:


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


no progress






lack mandate/funds/time


volunteer needed

  1. (tick) NC: move/copy all the classes (specified above) into new module 'gt-complex'
  2. (tick) NC: refactor app-schema to use the gt-complex module and the new featuretyperegistry
  3. (tick) NC: Pull request for GEOT-4344 
  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.