Enum mixin?

From:
"A. W. Dunstan" <no@spam.thanks>
Newsgroups:
comp.lang.java.programmer
Date:
Fri, 21 Oct 2011 17:19:29 -0400
Message-ID:
<WsudnUpWT_V6fDzTnZ2dnUVZ_vCdnZ2d@speakeasy.net>
I'm writing a GUI that's a wrapper around some Fortran code. In one of the
Fortran routines I pass in an integer that tells the Fortran code what kind
of 'cloud model' to use (it's a big physics simulation). For example:

value meaning
----- ---------
0 no clouds
1 cumulus
2 altostratus
18 cirrus

etc. The Fortran is 3'rd party software so changing values & their meanings
isn't an option.

I'd use a plain enum but the values passed in aren't continuous (as above -
it skips from 2 up to 18), nor do they necessarily start at zero. So I
wrote my own enum where I could associate a name, a value and a description:

public enum CloudModel {
    None(0, "No clouds"),
    Cumulus(1, "Cumulus"),
    AltoStratus(2, "Altostratus"),
    Cirrus(18, "Cirrus");

    CloudModel(int value, String description)
    {
        m_value = value;
        m_desc = description;
    }

    public int getValue() { return m_value; }

    public String toString() { return "" + m_value + ": " + m_desc; }

    private int m_value;
    private String m_desc;
}

This works but I'm now up to six different enums (Cloud coverage,
atmospheric model, haze, surface reflectance, etc), and they all look nearly
the same. Each one has identical getValue() and toString() methods, m_value
and m_desc. And the constructor varies only in it's name - the body of each
constructor is the same. Creating a new enum is easy - cut & paste, change
the name of the constructor, type in the values and I'm done.

This works too, but code reuse by cut-and-paste worries me. I'd like to
extract the methods & member variables into a base class of some sort and
extend that, providing the enumeration values in each derived enum. BUT - I
can't extend from an enum. If I could put the common parts in a separate
class and mix that in (as in Ruby) that'd be great, but Java isn't Ruby.

My code will be called from Matlab (which can access Java objects & methods
directly) so I'd like to keep it as an enum. And enums are easy to load
into a JComboBox, which makes that part of the GUI code cleaner.

I'm ok with leaving it the way it is, but does anyone know of a better
approach? Preferably one that's not so complex that it's worse than my
current state of affairs?

--
Al Dunstan, Software Engineer
OptiMetrics, Inc.
3115 Professional Drive
Ann Arbor, MI 48104-5131

"There are two ways of constructing a software design. One way is to
make it so simple that there are obviously no deficiencies. And the
other way is to make it so complicated that there are no obvious
deficiencies."
            - C. A. R. Hoare

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