ISPN-5345 Allow eviction for based on approximation of size compared to element count

[tristantarrant]

https://issues.jboss.org/browse/ISPN-5345

• Added in size calculation for byte[] key/value pairs with LRU

This supersedes' @wburns #3467 and introduces the following changes:

• add type=COUNT|MEMORY to choose how to evict entries
• add size which replaces maxEntries and works for both types
• add a warning when not running under HotSpot
• add a MemoryUnit utility class inspired by TimeUnit

[danberindei]

@tristantarrant I liked your previous suggestion much better... I'd rather have two different attributes/elements with clear names than a generic thresholdSize that doesn't say anything.

To add yet another suggestion: How about deprecating the <eviction max-entries="x"/> element and adding <eviction-count max-entries="x"/> and <eviction-memory max-size="x"/> to replace it? Would that complicate things too much?

[tristantarrant]

Supporting that for embedded is reasonable, it is server which always causes head-scratching and pain, since we need to think about how to represent those "nodes" in the management model in a non ambiguous way

[tristantarrant]

@danberindei using type and size now

[tristantarrant]

CI failures are unrelated

[danberindei]

You can remove these

[tristantarrant]

They are gone

[danberindei]

Should be size() and type()

[tristantarrant]

Silly, me, fixed now

[danberindei]

Integrated, thanks Tristan!