Reorganize project directory structure

[desruisseaux]

Current directory structure is (simplified, e.g. omitting the test directories):

  geoapi
   ├─ geoapi
   │   └─ src
   │       └─ main
   │           ├─ java
   │           │   └─ org
   │           │       └─ opengis
   │           │           └─ metadata, etc.
   │           └─ python
   │               └─ ogc
   │                   └─ metadata, etc.
   ├─ geoapi-pending
   ├─ geoapi-conformance
   ├─ geoapi-java-python
   ├─ geoapi-examples
   ├─ geoapi-netcdf
   ├─ geoapi-proj4
   ├─ geoapi-gdal
   └─ src
       └─ main
           └─ asciidoc
               └─ specification.adoc

This layout has many issues:

• No clear separation between standard parts, bridges and examples.
• Incompatible with Java 9 modularization (Jigsaw) using --module-path.
• Files related to the same language (Java or Python) are spread far to each other.
• Difficult to find code examples because of explosion in amount of folders.

We also need to reorganize the specification in ASCIIDoc format to match the OGC standard template. A proposal is available on the restructuring branch:

geoapi
 ├─ pom.xml
 ├─ standard
 │   ├─ pom.xml
 │   ├─ asciidoc
 │   │   └─ specification.adoc
 │   ├─ java
 │   │   ├─ org.opengis.geoapi
 │   │   │   ├─ classes
 │   │   │   │   └─ org
 │   │   │   │       └─ opengis
 │   │   │   │           ├─ metadata
 │   │   │   │           └─ referencing
 │   │   │   └─ tests
 │   │   │       └─ org
 │   │   │           └─ opengis
 │   │   │               ├─ metadata
 │   │   │               └─ referencing
 │   │   ├─ org.opengis.geoapi.conformance
 │   │   └─ org.opengis.geoapi.bridge.python
 │   └─ python
 │       ├─ ogc
 │       │   ├─ metadata.py
 │       │   ├─ referencing.py
 │       │   └─ bridge
 │       │       └─ java.py
 │       └─ test_metadata.py
 └─ examples
     ├─ pom.xml
     ├─ java
     │   ├─ org.opengis.geoapi.examples
     │   ├─ org.opengis.geoapi.wrapper.netcdf
     │   ├─ org.opengis.geoapi.wrapper.proj4
     │   └─ org.opengis.geoapi.wrapper.gdal
     └─ python
         └─ ogc
             └─ wrapper
                 └─ gdal.py

Notes:

• This restructuring abandons the Maven standard directory layout, since I have been unable to meet above-cited goals with that layout. For example there is still no way to generate satisfying aggregated Javadoc with Maven on Jigsaw (MJAVADOC-449).
• Insertion of Jigsaw modules (org.geoapi.foo directories) under src/main/java is not Maven-standard, but those directories are Java-standard since JDK 9 when using Java tools with --module-path option. This is an incompatibility between Maven conventions and Jigsaw conventions which is one reason why we abandon Maven contentions.
• Not everything in the standard directory is normative. In particular the org.opengis.geoapi.pending module shall not be included in any OGC standard. It is there only during development, for making easier to experiment new features.
• The org.opengis.geoapi.bridge.python module is required for running org.opengis.geoapi.conformance on a Python implementation.

[desruisseaux]

Created a new branch for experimenting the directory layout reorganization:

• https://github.com/opengeospatial/geoapi/tree/restructuring

This branch does not compile yet and will probably be rebased often. It is provided only for discussion and experimentation purposes.

Also created a project and wiki page for changes in Maven plugins:

• https://github.com/Geomatys/maven-plugins/wiki

[desruisseaux]

Deleted restructuring branch. It has not been updated for 4 years. We abandon the plan to deviate from Maven conventions in this project. Instead, the problems raised in this issue are partially resolved by moving demonstration implementations to separated projects, in particular:

• https://github.com/OSGeo/PROJ-JNI
• https://github.com/Unidata/geoapi-netcdf-java