I don't understand enums

ptomblin+netnews@xcski.com (Paul Tomblin)
Sat, 26 Jan 2008 22:45:33 +0000 (UTC)
I have some existing code that uses the classic old

class Playlist
  public static final int PLAYLISTTYPE_FEATURE = 1;
  public static final int PLAYLISTTYPE_TRAILER = 2;

But now that we're using Java 1.5, I've got new code where I decided to
use a Java 1.5 enum:

public enum PlaylistType
    FEATURE(1, "Feature"),
    TRAILER(2, "Trailer"),

    final int id;
    final String name;

    PlaylistType(final int id, final String name)
        this.id = id;
        this.name = name;

    public int getID()
        return id;

    public String toString()
        return name;

In order to make sure the new code and the old code work together, I
changed the definition of the old ints to
  public static final int PLAYLISTTYPE_FEATURE = PlaylistType.FEATURE.getID();
  public static final int PLAYLISTTYPE_TRAILER = PlaylistType.TRAILER.getID();

Note that they're still "public static final".

But now case statements that worked before the change are breaking with
Eclipse complaining that "case expressions must be constant expressions".
Huh? They sure look constant to me. How could it think that
PLAYLISTTYPE_FEATURE could change values when it's declared final?

Paul Tomblin <ptomblin@xcski.com> http://blog.xcski.com/
while true do; mutt -Z; trn; vi; make; done # My typical day

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