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Posted to dev@sis.apache.org by Martin Desruisseaux <ma...@geomatys.fr> on 2013/09/29 19:24:11 UTC

Doodle about a possible "Unit of Measurement" JSR

Hello all

A "Unit" class has always been problematic in GeoAPI/Geotk and other 
projects. Unit of Measurement are keys to interoperability while much 
wider in scope than GIS, so we would expect a standard API for that. 
Unfortunately the two previous Java Specification Request attempts 
(JSR-108 and JSR-275) failed for different reasons. This has lead to the 
uncomfortable situation where GeoAPI and SIS depend on an API 
("javax.measure.unit") which is officially dead, unless a new JSR is 
restarted. Even in the JDK itself, the lack of standard Unit class has 
leaded to a variety of redundant classes: TimeUnit [1] versus 
TemporalUnit [2] and ChronoUnit [3], and at least three different 
Duration classes [4,5,6].

The former JSR-275 lead has started a doodle in order to get opinions 
about whether a third Unit Of Measurement JSR should be attempted, or if 
we should stick with existing API. For GeoAPI/Apache SIS the implication 
is whether we stick to the current officially dead "javax.measure.unit" 
API in the hope that a new JSR will bring it back to live, or stop 
waiting and move to "org.unitsofmeasurement" [7] at the risk of having 
to switch back again to the "javax.something" if a new JSR succeed.

If anyone would like to express his opinion, the doodle is there:

     http://doodle.com/v6p8p42gcd9xn94k?

If anyone feels he could volunteer for such JSR, that would also be great!

     Martin


[1] 
http://download.java.net/jdk8/docs/api/java/util/concurrent/TimeUnit.html
[2] 
http://download.java.net/jdk8/docs/api/java/time/temporal/TemporalUnit.html
[3] 
http://download.java.net/jdk8/docs/api/java/time/temporal/ChronoUnit.html
[4] http://download.java.net/jdk8/docs/api/javax/xml/datatype/Duration.html
[5] http://download.java.net/jdk8/docs/api/java/time/Duration.html
[6] http://docs.oracle.com/javafx/2/api/javafx/util/Duration.html
[7] http://www.unitsofmeasurement.org