Sponsoring getting 5015163 "(str) String merge/join that is the inverse of String.split()" into JDK 7

[Joe Darcy]

Joe Darcy wrote:
> Rémi Forax wrote:
>> Le 14/10/2009 01:32, Joseph D. Darcy a écrit :
>>> Hello.
>>>
>>> Following up from threads earlier this year,
>>>
>>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2009-February/001061.html 
>>>
>>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2009-March/001191.html 
>>>
>>>
>>> I'm willing and interested to sponsor getting String.join 
>>> functionality into JDK 7.
>>>
>>> To address this particular bug, I think there should be new "join" 
>>> methods on String as opposed to a general "joiner" class.  A more 
>>> general class could be added later.
>>>
>>> Remi, please point to a current draft of the specification and 
>>> implementation for your change.
>>>
>>> Kevin, I'm interested in hearing your comments on the API design.
>>>
>>> Thanks,
>>>
>>> -Joe
>>
>> Hi Joe,
>> the webrev is here:
>> http://cr.openjdk.java.net/~forax/5015163/webrev.00/
>> There is no specification, i.e no more than the javadoc.
>>
>> I will dig this evening to find the tests I've used,
>> they are on another computer at home which is currently shutdown.
>>
>> As Kevin said String.join is perhaps better as a static method,
>> see first part of:
>> http://mail.openjdk.java.net/pipermail/core-libs-dev/2009-February/001065.html 
>>
>
> Yes, I'd also lean toward static methods for this functionality.
>
>

Following up on this, what is the exact revised proposal?

In java.lang.String:

    public static String join(String separator, Iterable<?> objects);
    public static String join(String separator, Object[] objects);
    public static String join(String separator, Object first, Object... 
rest);

with analogous methods in StringBuffer and StringBuilder return that 
type, respectively, instead of String?

I assume the motivation for having both the Object[] and (Object, 
Object...) versions is to avoid unnecessary array creation in the case 
of one argument since the single method join(String, Object...) could 
also be used.

-Joe