RFR(m): 8139233 add initial compact immutable collection implementations

[Peter Levart]

Hi Stuart,


Good to see these implementations finally appear. I have a few comments:

- What's the point of 11 overloaded List.of() methods for 0 ... 10-arity 
if you then invoke the var-args ListN(E...input) constructor that does 
the array cloning with 8 of them? The same for Set.of()... I suggest 
that you don't clone the array in ListN(E... input) constructor but only 
in List.of(E ... input) method.
- {Set0, Set1, Set2}.contains(null) return false, but 
SetN.contains(null) throws NPE. All List{0,1,2,N}.contains(null) return 
false. What should be the correct behavior? 
ConcurrentHashMap.keySet().contains(null) throws NPE for example.
- SetN.probe(E pe) and MapN.probe(K pk) invoke ee.equals(pe) and 
ek.equals(pk) respectively. Although it should be logically equivalent, 
it has been a practice in collections to invoke the .equals() method on 
the passed-in argument rather than on individual elements of the collection.
- Should unchecked exceptions from constructors be wrapped with 
InvalidObjectException in SerialProxy.readResolve() or does the 
Serialization infrastructure already perform the equivalent?

Regards, Peter

On 05/04/2016 06:55 AM, Stuart Marks wrote:
> Hi all,
>
> This is a reimplementation of collections created by the JEP 269 
> convenience factory methods. These implementations are overall quite a 
> bit smaller than their conventional collections counterparts, 
> particularly at small sizes. Lookup performance for the hash-based 
> structures (Set and Map) is not particularly fast, though in most 
> cases it's comparable to TreeSet/TreeMap. Further improvements are 
> likely possible.
>
> There are no API changes in this changeset.
>
> Please review:
>
>     http://cr.openjdk.java.net/~smarks/reviews/8139233/webrev.0/
>
> JEP link:
>
>     http://openjdk.java.net/jeps/269
>
> Thanks,
>
> s'marks