On Apr 17, 2011, at 11:52 AM, Joanna Carter wrote: > Tell me; maybe it's my background in other languages, but I would tend to use > a "static class" as a singleton; or, at least, design a class with only class > methods/properties, with static "fields" declared in the @implementation > section of a class. > > Why this fascination with going to all the trouble of creating a singleton > rather than using the "static class" approach?
A narrow technical reason: Objective-C's type system is limited when it comes to class objects. Singleton instances are better supported. A software lifecycle reason: Sometimes an app evolves such that a task that used to be performed globally now needs to have multiple different local contexts. (Perhaps you wrote a single-window app with a singleton window controller, and now you want a multiple-window app.) Code written for a singleton instance can often be transformed to work with multiple instances. Code written for a static class may need more rewriting to handle the change. -- Greg Parker gpar...@apple.com Runtime Wrangler _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
