ConcurrentHashMap/ConcurrentMap/Map.compute

[Doug Lea]

On 12/14/12 13:27, Brian Goetz wrote:

> Would be useful if you could dig up.  Very often the problem is not an issue
> with a specific name, but their relationships, which mean they sometimes need to
> be considered as a group.
>

See September and October 2011 archives at:
http://cs.oswego.edu/pipermail/concurrency-interest/
Plus a few scattered followups. On rescan I see that
the sequence of events was first to support only
computeIfAbsent. Then also a form of compute called recompute
that initially didn't allow null arg or return so couln't
be used for initialization or removal. Then changing this but
adding computeIfPresent to better support update-only usage.
Then merge was added months later to better handle groupBy etc.

Note that the only method you minimally need is compute.
But the others avoid need for transient captures/lambdas,
non-transparent effects, and extra work inside implementations.
So it is likely in practice to be the least well used.
In which case (sour grapes mode) having an odd name is not so bad.

-Doug