延迟加载

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

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.)

Lazy Loading

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