[concurrency-interest] Adding a createIfAbsent() API?

[Kasper Nielsen]

Sorry for bringing up this old discussion, but since we have Ops.Mapper 
now. Wouldn't it make sense to add

V createIfAbsent(K key, Ops.Generator<? extends V> generator)
and
V createIfAbsent(K key, Ops.Mapper<? super K, ? extends V> mapper)

to ConcurrentHashMap and ConcurrentSkipListMap

- Kasper

Rowlands, Ben (IT) wrote:
> I often find a need for an API like:
> 
>   public V createIfAbsent( K key, Callable<V> creator ) throws
> ExcecutionException
> 
> Similar in operation to putIfAbsent() but taking a callback that is used
> to resolve the value if one isn't found at at the key. 
>