Comments on: Annoying Patterns: The Hidden ‘On’ Switch http://squadlimber.com/chris/2007/03/15/anti-patterns-the-hidden-on-switch/ software development that works...or something Fri, 21 Nov 2008 09:04:29 +0000 http://wordpress.org/?v=2.0.5 by: Duncan Pierce http://squadlimber.com/chris/2007/03/15/anti-patterns-the-hidden-on-switch/#comment-6 Fri, 06 Apr 2007 13:42:24 +0000 http://squadlimber.com/chris/2007/03/15/anti-patterns-the-hidden-on-switch/#comment-6 Yep, this kind of thing is really irritating. Sometimes you feel like there's a whole hidden state machine in there. <code> api.doStuff(1); api.doStuff(2); Exception: doStuff(1) called without init() api.init(); api.doStuff(1); api.doStuff(2); Exception: doStuff(2) called without finish() api.init(); api.doStuff(1); api.finish(); api.doStuff(2); // aargh - should there be a finish() here? } </code> If the code is able to validate its own state it ought to be able to manage it for you too. The fact that it can't is usually down to poor API design: they often carry too much state. Yep, this kind of thing is really irritating. Sometimes you feel like there’s a whole hidden state machine in there.


api.doStuff(1);
api.doStuff(2);

Exception: doStuff(1) called without init()

api.init();
api.doStuff(1);
api.doStuff(2);

Exception: doStuff(2) called without finish()

api.init();
api.doStuff(1);
api.finish();
api.doStuff(2);
// aargh - should there be a finish() here?
}

If the code is able to validate its own state it ought to be able to manage it for you too. The fact that it can’t is usually down to poor API design: they often carry too much state.

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