Re: Singleton Implementation Issue

Smithers,

If you are going to do that, then the singleton pattern doesn't really
apply. The whole point is that you have one instance here.

Now, having a property that returns that instance is fine (it doesn't
matter if it is a property or a method), but if the method takes parameters,
and the values passed to that method could change, then what do you do the
second time the method is called with different parameters? Do you return
the same instance?

It sounds like what you really want is something along the lines of a
class factory, which returns cached instances based on the parameters passed
in.

--
- Nicholas Paldino [.NET/C# MVP]
- mvp@xxxxxxxxxxxxxxxxxxxxxxxxxxx

"Smithers" <A@xxxxx> wrote in message
news:ufe1dS60HHA.5764@xxxxxxxxxxxxxxxxxxxxxxx
Unless I'm misunderstanding the pattern and it's various implementations,
Singleton effectively makes the constructor unavailable to clients. The
constructor for any given class, however, is what we otherwise use
[outside of Singleton implementations] to *require* specific parameters be
supplied upon instantiation (provided of course that we've removed the
default constructor).

So my question: I want to have a Singleton implementation that requires
specific parameters to be supplied upon instantiation.

My initial shot at a reasonable answer (please provide your thoughts on
this):
1. I'll go with one of the Singleton implementations that results in lazy
instantiation.
2. Then, in order to *require* the parameters to be supplied, I'll have a
*method* named Instance() instead of a *property* of that name. The method
then defines the arguments for which clients are to supply the parameter
values upon accessing the Singleton.

Thoughts? Considerations? Perspective?

Thanks.



.

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