JEP 186: Collection Literals

[Brian Goetz]

This is a very valid point, and one that has been raised before -- that 
maybe this doesn't need a language feature, that maybe simply some 
library changes would be enough.

In fact, since the goal at this point is to discuss whether we should 
move forward or not with the /exploration/ of the language feature, let 
me restrict the discussion to this point: is this something that needs a 
language feature, or would library support be enough?  Bear in mind that 
the cost of even a simple language feature is probably 100x that of a 
comparable library feature, cost-benefit is an important consideration.

On 1/14/2014 12:02 PM, Klaus Malorny wrote:
> On 14.01.2014 17:33, Nick Williams wrote:
>   > I think we should also try to keep the Java Unified Expression Language in
>   > mind while designing this. Java EE 7 added lambda expressions to JUEL. Can
>   > you imagine how confusing it would have been if they had defined a different
>   > lambda syntax than Java 8? They didn't, though. They made the syntax mirror
>   > Java 8 lambdas.
>   >
>   > JUEL also has collection literals now, and I think it would be foolish to
>   > define a literal syntax different than that defined in JUEL. It will make
>   > developers' lives more difficult. The JUEL syntax is simple and I think it
>   > would work perfectly in Java as well:
>   >
>   > List: [ 1, 2, 3 ] Set: { 1, 2, 3 } Map: { "one" : 1, "two" : 2, "three" : 3
>   > }
>   >
>   > If we, for example, make Lists use curly braces in Java when they already use
>   > square brackets in JUEL, that would be unfortunate.
>   >
>   > Nick
>   >
>
>
> Hi,
>
> if I may add my two cents: I have solved the problem for me by
>
> - having a static setOf (...) method to construct sets, which
>     is imported via static import if need be
> - having a static mapOf (key, value) method which is the start
>     of a call chain, ending with map (), which returns the constructed
>     map,
>
>     e.g. Map<String, Integer> map = mapOf ("one", 1).put ("two", 2).
>            put ("three", 3).map ();
>
> Overloaded and alternative methods allow me to create unmodifiable sets and
> maps, including EnumMaps, also to perform some additional checks for EnumMaps
> (e.g. whether all keys occur). Similar could be done for lists, of course.
>
> So while I do not dislike collection literals, I just want to point out that the
> keyboard typing benefit isn't that great IMHO.
>
> Regards,
>
> Klaus
>