Replace concat String to append in StringBuilder parameters

[Pavel Rappo]

Ulf,

My point was simply that none of these classes provide methods that accept java.lang.Object. IMO, the scenario when we join elements into a String by calling toString on each element prior to append it -- is the most common scenario (maybe except for when element is a String itself). That is instead of doing this:

	Iterable<?> whatever = ...
	String s = String.join(whatever);

we have to do (at least) something like this:

	Iterable<?> whatever = ...
	whatever.forEach(w -> builder.append(w.toString());
	String s = builder.toString();

or this:

	String s = StreamSupport.stream(whatever.spliterator(), false /* or true */)
        	                .map(Object::toString)
                	        .collect(Collectors.joining(", "));

That is, it's hardly ever a concise one-liner. An 'addAll' method in j.u.StringJoiner could have saved us, but there isn't one.

(I'm sure there were plenty of engineering reasons not to do things I've mentioned)

-Pavel

On 11 Aug 2014, at 16:38, Ulf Zibis <Ulf.Zibis at CoSoCo.de> wrote:

> 
> Am 11.08.2014 um 16:33 schrieb Pavel Rappo:
>> Unfortunately, neither java.util.StringJoiner nor String.join have perfect (but who has?) APIs. So it's up to us to figure out the best way of joining elements.
> 
> Maybe remember my thoughts from here:
> http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-April/016172.html
> http://mail.openjdk.java.net/pipermail/core-libs-dev/2014-January/024761.html
> 
> Would it be possible to inherit StringJoiner from StringBuilder in some way?
> Then a mixture of concatanation, StringBuilder and StringJoiner after Javac would end up in one StringBuilder instance. We also could profit from StringJoiners initial capacity capability.
> 
> -Ulf
> 
>