Re: [Flashcoders] Extending a singleton
The typical situation is that you do vice versa, that is extend some object, and then make the child object a Singleton... Regards /Eskil Christophe Herreman skrev: Hi guys, I was wondering if anyone of you ever had a situation where it would be good to extend a singleton. The first question is: Is it good practice or should it be avoided at all cost? Anyway, I have been trying to extend one, but the problem is that instance variables are not accessible in the class that extends the singleton (and which is also a singleton). So for instance, take a class A that has a properties instance variable that holds key/value pairs. That var is initialized in the constructor. A.getInstance() gives me the single instance. B extends A, and B.getInstance() gives me the single instance of B. But since it extends A, A's constructor is called (although it is private, a camouflaged protected in AS2) and the properties var is instantiated again. Get the picture? B will have a properties instance var but it will not be the same as the one in the singleton of A. Am I overlooking something very obvious here or is this actually hard to accomplish? I changed it from inheritance to using A.getInstance() internally which works; but now I have to add wrapper methods for every method in A/ /I want to make available. thx in advance, Christophe ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
RE: [Flashcoders] Extending a singleton
When I extend a singleton I expect it to do exactly what you are saying. Maybe you need to rethink the way you are structuring things. I would keep them as 2 singletons with B referencing A for vars you need the same value on. Im tired so im not sure if that made sense. Jim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Christophe Herreman Sent: 23 March 2006 15:38 To: flashcoders@chattyfig.figleaf.com Subject: [Flashcoders] Extending a singleton Hi guys, I was wondering if anyone of you ever had a situation where it would be good to extend a singleton. The first question is: Is it good practice or should it be avoided at all cost? Anyway, I have been trying to extend one, but the problem is that instance variables are not accessible in the class that extends the singleton (and which is also a singleton). So for instance, take a class A that has a properties instance variable that holds key/value pairs. That var is initialized in the constructor. A.getInstance() gives me the single instance. B extends A, and B.getInstance() gives me the single instance of B. But since it extends A, A's constructor is called (although it is private, a camouflaged protected in AS2) and the properties var is instantiated again. Get the picture? B will have a properties instance var but it will not be the same as the one in the singleton of A. Am I overlooking something very obvious here or is this actually hard to accomplish? I changed it from inheritance to using A.getInstance() internally which works; but now I have to add wrapper methods for every method in A/ /I want to make available. thx in advance, Christophe ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com ___ Flashcoders@chattyfig.figleaf.com To change your subscription options or search the archive: http://chattyfig.figleaf.com/mailman/listinfo/flashcoders Brought to you by Fig Leaf Software Premier Authorized Adobe Consulting and Training http://www.figleaf.com http://training.figleaf.com
