"GetOrCreate" - does that idiom have an established name?

Question

Ok, consider this common idiom that most of us have used many times (I assume):

class FooBarDictionary
{
    private Dictionary<String, FooBar> fooBars;

    ...

    FooBar GetOrCreate(String key)
    {
        FooBar fooBar;

        if (!fooBars.TryGetValue(key, out fooBar))
        {
            fooBar = new FooBar();
            fooBars.Add(key, fooBar);
        }

        return fooBar;
    }
}

Does it have any kind of established name?

(Yes, it's written in C#, but it can be "easily" transferred to C++. Hence that tag.)

Answer 1

Lazy Loading

http://en.wikipedia.org/wiki/Lazy%5Floading

Answer 2

I always call such functions obtainSomething().

Answer 3

It sort of depends why you're doing it - the idiom is one I've seen be called memoization, caching, initialisation on demand, create on first use. Normally I call the method "ensureFoo" rather than "GetOrCreate"

Answer 4

I'm unsure of overall programming name for the high level pattern, but Perl has this wonderful behavior called Autovivification - namely, automatically creating hash (map) key with undefined value when you're querying the value of non-existing key in the hash.