RFR(m): 8177290 add copy factory methods for unmodifiable List, Set, Map

Roger Riggs Roger.Riggs at Oracle.com
Thu Sep 21 19:16:20 UTC 2017

Hi Stuart,

The new text in Collections reads more like an @apinote than a 
Are there any enforceable  assertions there?

I think the markup used to refer to unmodifiable XXX reads better as a 
link in
the text (as in Collection#unmodifableCollection)
than as a second sentence (as in List#of()).
A consistent treatment in all class would be a plus.

The implementations of the Collectors are very inefficient, first 
creating a mutable version,
then extracting to an array, and then constructing the final object.  So 
much garbage is created, especially for small n.

Thanks, Roger

On 9/21/2017 2:55 PM, Stuart Marks wrote:
> On 9/21/17 5:42 AM, Alan Bateman wrote:
>> On 21/09/2017 01:02, Stuart Marks wrote:
>>> http://cr.openjdk.java.net/~smarks/reviews/8177290/webrev.0/
>> I read through the updated/new definitions and they read well.
> Great.
>> For the copyOf methods then I can't immediately tell from the javadoc 
>> if the
>> given collection can contain null elements. Taking List.copyOf as an 
>> example
>> where coll may be null or it may contain null elements. The javadoc 
>> does link to
>> "Unmodifiable lists" where it specifies the characteristics of the lists
>> returned by the static factory methods - these include disallowing null
>> elements. So I think this needs to be clarified.
> Agreed, I'll work on some clarifications here, and also disallow null 
> for the argument itself.
>> Minimal implementation is okay to get started but what is the reason 
>> not to
>> include some basic tests?
> Sorry, I should have been more clear about this. The changeset is 
> clearly not ready to go in as it stands. I wanted to get an initial 
> review of the specifications going, then file a CSR request, etc. 
> while continuing to work on tests and better implementations. I'll 
> post a subsequent review when they're ready.
> Thanks.
> s'marks

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