RFR: 7057785 : (xs) Add note to hashCode() that support for self referential is optional

[Joe Darcy]

Hi Mike,

Looks good to go back; cheers,

-Joe

On 9/30/2013 2:29 PM, Mike Duigou wrote:
> Ping!
>
> (still need a Reviewer on this issue)
>
> Mike
>
> On Sep 16 2013, at 15:49 , Mike Duigou wrote:
>
>> Ping!
>>
>> (still need a reviewer on this)
>>
>> Mike
>>
>> On Sep 4 2013, at 11:44 , Mike Duigou wrote:
>>
>>> Hello all;
>>>
>>> I have updated the proposed changeset for this issue. I have moved the note to the interface documentation for Collection and Map and made it more general:
>>>
>>>> Some collection operations which perform recursive traversal of the
>>>> collection may fail with an exception for self-referential instances where
>>>> the collection directly or indirectly contains itself. This includes the
>>>> {@code clone()}, {@code equals()}, {@code hashCode()} and {@code toString()}
>>>> methods. Implementations may optionally handle the self-referential scenario,
>>>> however most current implementations do not do so.
>>> The webrev is at:
>>>
>>> http://cr.openjdk.java.net/~mduigou/JDK-7057785/1/webrev/
>>>
>>> Mike
>>>
>>> On Aug 27 2013, at 19:06 , Mike Duigou wrote:
>>>
>>>> Hello all;
>>>>
>>>> Fairly frequently it is reported that various Collection/Map implementations of hashCode() fail when the instance directly or indirectly contains itself. For a variety of reasons, mostly performance and resource related, most implementations choose not to support calculation of hash codes for self-referential collections. This is not likely to change. So to reduce confusion and "bug" reports I am proposing a non-normative @apiNote be added to Collection and HashMap. The text of the proposed note is:
>>>>
>>>>> Support for calculation of hash code by self referential {Collection|Map}s (they either directly or indirectly contain themselves) is optional. Few Collection implementations support calculation of hash code for self referential instances.
>>>>
>>>> http://cr.openjdk.java.net/~mduigou/JDK-7057785/0/webrev/
>>>>
>>>> Cheers,
>>>>
>>>> Mike