Michaël Michaud wrote: > > @Martin : Please, can you explain what immutability means for > coordinates. I see that x,y,z are public fields (and I remember I often > changed them via small scripts, especially the z value). But may be I > have no clear idea about immutability and its advantages. > >
Well, it's pretty simple. If you have a tool that works by altering the ordinate values in a Coordinate, and you are using the "interned Coordinate" strategy, you are going to get bugs, since Geometrys will change unexpectedly when their shared Coordinate values are changed by someone else. The public x,y,z in Coordinate were originally there for efficiency reasons. Probably a bad idea. In fact, Coordinate should have simply been an interface. But too late to change now! However, an application like JUMP should make it a blanket policy that Coordinate values should never by changed. Any other policy leads to insanity, IMO. HTH - Martin -- Martin Davis Senior Technical Architect Refractions Research, Inc. (250) 383-3022 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
