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Re: singleton usage [message #47604]

Tue, 21 February 2006 10:28

JD Smith
Messages: 850
Registered: December 1999

Senior Member

On Tue, 21 Feb 2006 15:47:26 +0100, Antonio Santiago wrote:

> vcarlos wrote:
>> Hi Antonio,
>>
>> I saw the system variable singleton implementation, but what I am in
>> doubt is about the usage of the pattern itself. Since everytime I need a
>> reference to the singleton object in my objects I need to call a
>> myObject = Singleton() statement, or initialize an attribute in every
>> object needing a reference to the singleton. But what if I just create a
>> read only system variable and use it over my whole program? (this
>> variable would be an instance of my "singleton" class)
>>
> Ok sorry, I don't understand you in the first email. Yes, I think you can
> do it, but this is a convention that you use in your program. Then you
> need to document very well that variable XXX is a "reference" to a
> singleton object in your whole application.

Using a singleton generator is easy (see various threads dating back
several years). As far as preventing rogue "obj_new()" calls, you can
also check the common block or system variable explicitly in the Init
function and generate an error if anyone uses it directly (except for
the first call).

JD

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[Message index]

		Re: singleton usage By: JD Smith on Tue, 21 February 2006 10:28
		Re: singleton usage By: Antonio Santiago on Tue, 21 February 2006 06:47
		Re: singleton usage By: vcarlos on Tue, 21 February 2006 06:06
		Re: singleton usage By: Antonio Santiago on Tue, 21 February 2006 05:58

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