Name of pattern associated with FindCreate() ?

[brianh@metamilk.com]

Hi -
I'm wondering if there is a name for the pattern where you consider
that every element of the set of resources of some type T already
exists and element access is via some method such as FindCreate(...)
since this seems a very common pattern.

(ie is there a proper word in pattern lingo or philosophy to describe
this other than just "FindCreate")

Thanks,

BrianH.

[SP]

<brianh@metamilk.com> wrote in message
news:1118327306.059999.260090@f14g2000cwb.googlegroups.com...
> Hi -
> I'm wondering if there is a name for the pattern where you consider
> that every element of the set of resources of some type T already
> exists and element access is via some method such as FindCreate(...)
> since this seems a very common pattern.
>
> (ie is there a proper word in pattern lingo or philosophy to describe
> this other than just "FindCreate")
>
> Thanks,
>
> BrianH.

FindCreate implies that the "resource" may or may not already exist. An
IdentityMap is a pattern used for checking if the "resource" already exists.
If it does not then it will need to be created using one of the creation
patterns (Factory, AbstrctFactory etc.). As a common place to find objects
look at the Registry pattern [PoEAA].

SP

[brianh@metamilk.com]

> FindCreate implies that the "resource" may or may not already exist.

Yes - I'm not that keen on the word "FindCreate" for this reason. I'd
like to be able to describe the situation where conceptually every
member of the type *eternally* exists but at a lower level this
"eternal existence" is implemented by objects that are
created/destroyed as necessary to represent the higher level "eternal"
objects.

An example of such higher level "eternal" objects are modules in a
module system where the (infinite) space of modules is considered to be
fully populated even though only a finite subset are non-empty, or
strings, where you only need to represent the strings you're actually
using but all possible strings already exist conceptually.

> An
> IdentityMap is a pattern used for checking if the "resource" already exists.
> If it does not then it will need to be created using one of the creation
> patterns (Factory, AbstrctFactory etc.). As a common place to find objects
> look at the Registry pattern [PoEAA].

Thanks for the pointers to different patterns and PoEAA -
Regards, Brian.