Collectors update

[Joe Bowbeer]

I like the way collect() parses.  I think aggregate() is more descriptive
but also less appealing.

Given that collect() is a method of Stream, I don't think it will be
particularly challenging to teach.

I wouldn't object to aggregate() though.


On Tue, Jan 29, 2013 at 2:55 PM, Raab, Donald <Donald.Raab at gs.com> wrote:

> Having the method name "collect" is going to make it very hard to teach
> folks to use the streams API with GS Collections as it means something
> different than our "collect" method.  It may equally cause problems for
> folks using Groovy, Apache Commons Collections and JRuby as well.
>
>
> http://groovy.codehaus.org/groovy-jdk/java/util/Collection.html#collect(groovy.lang.Closure)
>
> http://commons.apache.org/collections/api-release/org/apache/commons/collections/CollectionUtils.html
>
> We've gone through the names accumulate, tabulate (not sure if there are
> others)...
>
> I know there is a dwindling list of good names, and I'll settle when there
> are none better, but this particular name has 30+ years of prior art in
> Smalltalk influenced circles.  It is one of the most commonly used methods
> in our library and these other languages/libraries.
>
> Again, I'd like to propose "aggregate" as an alternative.
>
> stream.aggregate(groupingBy(Foo::getBar))
>
>
> > -----Original Message-----
> > From: lambda-libs-spec-experts-bounces at openjdk.java.net [mailto:lambda-
> > libs-spec-experts-bounces at openjdk.java.net] On Behalf Of Brian Goetz
> > Sent: Tuesday, January 29, 2013 5:35 PM
> > To: lambda-libs-spec-experts at openjdk.java.net
> > Subject: Collectors update
> >
> > I've done some refactoring in Collectors to address some issues,
> > including approachability issues that were raised by Kevin.  See if you
> > like them.
> >
> > 1.  Rename to more verby names.  We now have
> >    groupingBy
> >    groupingReduce
> >    joiningWith
> >    partitioningBy
> >
> > instead of groupBy/mappedTo/partition.  This is designed to make it
> > more clear what is going on when you read code like:
> >
> >    stream.collect(groupingBy(Foo::getBar))
> >
> > by making it clear that groupingBy is not an action but a way of
> > describing the desired collecting.
> >
> > 2.  Break groupBy into two groups, groupingBy and groupingReduce.
> > While the distinction is somewhat arbitrary since groupBy *is* a
> > reduce, it is now more consistent with the method naming on Stream.
> >
> > 3.  Rename mappedTo(T->U) to joiningWith.
> >
> > 4.  Rejigger Partition to return an array again, with an explicit
> > lambda (which will likely be an array ctor ref) to make the array.
> > Eliminated the silly Partition class.
> >
> > 5.  Add more tests -- we now have full test coverage on groupingXxx but
> > not yet the others.
>
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