JEP 186: Collection Literals

[Remi Forax]

On 01/15/2014 06:04 PM, Per Bothner wrote:
> On 01/15/2014 03:44 AM, Zhong Yu wrote:
>> On Tue, Jan 14, 2014 at 7:17 PM, Per Bothner <per at bothner.com> wrote:
>>> For example, one could define:
>>>
>>> T v = { e1, ..., en}
>>>
>>> as syntactic sugar for:
>>>
>>> TB tmp = T.make_builder();
>>> tmp.add(e1); ..; tmp.add(en);
>>> T v = tmp.build();
>> How is this any better than
>>
>>       T.of(e1, ..., en);
>>
>> ? I don't see how the literal syntax helps code writers or code
>> readers in this case.
> I can think of two reasons:
>
> (1) Target-typing means you don't have to redundantly specify T:
>
> T v = { e1, ..., en};
>
> vs
>
> T v = T.of(e1, ..., en);
>
> (2) Using the T.of form requires allocating an array,
> which is then thrown away.
>
> I don't think (2) is a major justification. (1) may not
> be enough to justify a new language feature by itself,
> though one could argue it's a natural extension of the
> existing syntax for arrays.

I disagree for (1), if you take a look to java.util.EnumSet by example,
you will see that there are multiple overloads of 'of' to avoid to allocate
an array in the common cases.

Rémi