[geotk] Moving to Apache SIS

[Martin Desruisseaux]

Hello all

The Geotoolkit.org development is slowly moving to the Apache SIS 
project. We are in process of migrating the classes one-by-one, and 
deprecating the migrated Geotoolkit.org classes. For users, the most 
significant changes is that the "org.geotoolkit.*" package names will 
become "org.apache.sis.*". For example the 
"org.geotoolkit.referencing.crs.GeographicCRS" class in Geotoolkit.org 
will be copied (eventually with modifications) as 
"org.apache.sis.referencing.crs.GeographicCRS" in Apache SIS. The old 
Geotoolkit.org class will still be there as a deprecated class for at 
least one release cycle, so most existing code will hopefully not break 
without warning.

While doing the migration, we take the opportunity for fixing the 
following issues:

* Support of supplementary Unicode characters
* OSGi bundles
* Dependency injections
* Better concurrency
* Consolidation

The most important classes (metadata, referencing) are expected to stay 
the same. But some support classes get significant changes. For example 
the java.io.FilterWriter implementations (a legacy of pre-Java 5 days) 
in the "org.geotoolkit.io" package are replaced by java.lang.Appendable 
implementations.

The Apache SIS web site is not yet setup. However the following draft 
can be used in the main time:

https://builds.apache.org/job/sis-trunk/site/

The Apache SIS developer mailing list is more active than the Geotk one. 
For example I just posted a summary of today OGC meeting. Peoples having 
an interest in Geotk development are encouraged to register to the 
Apache SIS mailing list.

https://builds.apache.org/job/sis-trunk/site/mail-lists.html

In the long term, the Geotk project will continue to exist. It will keep 
all its current functionalities, because classes removed (after 
deprecation) from Geotk are replaced by dependencies to the equivalent 
Apache SIS classes. But Geotk will probably be used as a laboratory for 
classes not yet ready to move to Apache SIS. For this reason, the Geotk 
and Geotk-pending repositories will probably be merged. Geotk will also 
contain a few classes that can't be moved to Apache SIS for licensing 
reasons.

I apologize for the inconvenient that such change is causing to the 
users... However I feel that the gain of joining the Apache community is 
big and will hopefully justify the pain...

     Martin