Possible HashMap update

Doug Lea dl at cs.oswego.edu
Thu Aug 15 14:33:02 UTC 2013

On 08/14/13 09:23, Remi Forax wrote:
> On 08/14/2013 01:16 PM, Doug Lea wrote:
>> On 08/13/13 16:56, Remi Forax wrote:
>>>>>> And that the iterators on entrySet, keySet and values doesn't have their
>>>>>> method
>>>>>> forEachRemaining overriden
>>>>>> (unlike java.util.ArrayList).
>> Could you explain exactly when these trigger? Most Stream-related
>> operations should pick up spliterator, not iterator, so won't
>> encounter this.
> Yes, it's not related to Stream.
> I see two obvious scenarios when forEachRemaining should be used.
> The first one is bug 6360734 [1], for(:) doesn't support Iterator but there are
> plenty of methods in the wild that returns an Iterator.
> In the JDK, at least
>    BeanContextServices.getCurrentServiceClasses(),
>    BenContextSupport.bcsChildren() or
>    ServiceRegistry.getCategories(),
> all return something like map.[views()].iterator()
> The second scenario is when you have an algorithm that do something for first value
> and do something else for the other value, in that case, you need to get the
> iterator,
> calls next to get the first value and calls forEachRemaining for processing the
> remaining values.
>> I resist this a bit because it would require 6 more
>> methods, each redundant with a spliterator method.
>> (The HashMap view ones must be overridden in LinkedHashMap.)
>> But if the situation is common, it might be worthwhile.
> I suppose that it depends on what is your definition of common :)

Neither of these cases apply to existing usages, so I'm thinking
that they are not common enough to support. Does anyone else
think otherwise?


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