Change RotationOrder from final class to enum.

[BryanCazabonne]

Hi all,

By looking at the RotationOrder class, I was a little bit surprise to see that this object is declare as final class instead of an enumerate.

I think it could be a good enhancement to set this class as an enumerate. Another improvement can be to add a static map (Map<String, RotationOrder> CODE_MAP) attribute in order to access a RotationOrder Object from a String value. Therefore, the following method can be also added:

public RotationOrder getRotationOrder(final String name) {
     final RotationOrder type = CODE_MAP.get(name);
     if (type == null) {
          // Exception
     }
     return type;
}

What do you think about this change? If you think this change interesting, I can perform the development.

I'm asking that because some attitude standard files (CCSDS ADM for instance) give the rotation sequence of Euler angles as a String value. Hence, thanks to my proposal, the RotationOrder object corresponding to the rotation sequence can be easily created.

Kind regards, Bryan

[maisonobe]

This seems fine to me, but I am not sure it would be binary compatible with earlier versions. It would be source compatible, though, as we can only use the public final constants XYZ, XZY... because the constructor is private.

The class is a a very old one. I traced it back from the Mantissa library in... september 2002. At that time, the current Java version was 1.4, but the library was still compatible with Java 1.3. Enumerates were not available before Java 1.5.

[BryanCazabonne]

I understand the problem of compatibility. Even if this change is minor in terms of development, it is important because it changes the nature of the class.

I performed the development and ask for a pull request (see #73). I let you decide if this change can be added or not.