Re: Singleton --- Just Look and give Suggestion's
On Mar 7, 12:55 pm, Jeff Schwab <j...@schwabcenter.com> wrote:
James Kanze wrote:
On Mar 6, 5:49 pm, Matthias Buelow <m...@incubus.de> wrote:
anon wrote:
Then why are singleton questions appearing in this NG all
the time?
Spill over from Java?
C++ has global variables; singletons are just a very
bureaucratic way of achieving the same thing.
I couldn't put my finger on it before, but I think you've just
named the problem with Singleton. Well, not the problem,
exactly; the problem is that Singleton is over-used, and that
developers often call things Singletons that really aren't.
A singleton is a type, not a variable or an object.
Singleton is a design pattern. Either a type or an object may
fit that pattern, or some other entity yet to be imagined.
It's obviously a question of definition, but according to the
GoF, the intent of a singleton is to "ensure a class only has
one instance, and provide a global point of access to it." What
makes a singleton a singleton is the fact that there can only be
one instance of the type.
Of course, it's a free country, and like Humpty-Dumpty, you can
use the word to mean exactly whatever you want it to mean. But
using a meaning other than the generally accepted one isn't
going to help communications.
As for being overused... I haven't found this to be the case in
production code. It tends to be over-talked about, because it
is in many cases the first example of a design pattern that
people abord. But I'm not sure it's overused.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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