Brian,
Yes, this works fine in cases when 'whatever' is a j.u.Collection<? extends
CharSequence> (though some may argue that it's an overkill already). However we
need even more thinking and transformations in case when 'whatever' is one of
these:
* j.u.Iterator<? extends CharSequence>
* j.l.Iterable<? extends CharSequence>
* j.u.Enumeration<? extends CharSequence>
* CharSequence[]
In my opinion it's not that pretty:
* Enumeration<String> whatever = ...;
String s = Collections.list(whatever).stream().collect(joining(", "));
* Iterable<String> whatever = ...;
String s = StreamSupport.stream(whatever.spliterator(), false /* or true
*/)
.collect(Collectors.joining(", "));
When we have one of these, it's even worse:
* T[], where T is not an instance of CharSequence or T is primitive
int[] whatever = ...;
Arrays.stream(whatever).mapToObj(Integer::toString).collect(joining(", "));
* Iterable<Object> whatever = ...;
String s = StreamSupport.stream(whatever.spliterator(), false /* or true
*/)
.map(Object::toString)
.collect(Collectors.joining(", "));
I believe the most common case of joining objects into a string is either when
objects are strings itself or they are made strings by calling
Object::toString. For such a common and simple task there should be a
convenient and concise one-liner.
I may be missing something.
-Pavel
On 19 Aug 2014, at 01:43, Brian Goetz <brian.go...@oracle.com> wrote:
> What you should have written was:
>
> String s = whatever.stream().collect(joining(", "));
