Feedback on the implementation of StringJoiner

[Roel Spilker]

And subSequence could do a slightly better job:

 if (start < value.length()) {
            return new StringBuilder(value.subSequence(start, value.length()))
                        .append(suffix.subSequence(0, end - value.length()))
                        .toString();


is IMHO less performant than:

 if (start < value.length()) {
            return new StringBuilder(end - start)

                        .append(value.subSequence(start, value.length()))

.append(suffix.subSequence(0, end - value.length())) .toString();



On Wed, Dec 12, 2012 at 9:34 PM, Roel Spilker <r.spilker at gmail.com> wrote:

> Oh, and please remove the string concatenation from the constructor. Since
> prefix and suffix are stored separately and setEmptyOutput does not accept
> null values, a null-check on the field can be used to calculate the
> emptyOutput when it is needed. I think the common case is that the
> emptyOutput value is not read at all.
>
>
> On Wed, Dec 12, 2012 at 9:27 PM, Roel Spilker <r.spilker at gmail.com> wrote:
>
>> Well, a lot of code was removed, what is in my opinion always a good
>> thing.
>>
>> Apart from the comments already mentioned, I have one other point. The
>> JavaDoc of length(), charAt(int) and subSequence(int, int) still define
>> their behavior as being equivalent to the same operation on the toString()
>> result. However, the class isn't final. I don't think it is a promise that
>> should be made, because it puts quite a burden on a subclass. My preferred
>> solution would be to make the class final. However, I don't know if that is
>> an option.
>>
>> Roel
>>
>>
>>
>> On Tue, Dec 11, 2012 at 9:54 AM, Stephen Colebourne <scolebourne at joda.org
>> > wrote:
>>
>>> On 10 December 2012 16:26, Henry Jen <henry.jen at oracle.com> wrote:
>>> > I am doing some changes to adapt your feedbacks and trying to have
>>> minimum but enough APIs, latest proposed can be found at
>>> >
>>> > http://cr.openjdk.java.net/~henryjen/lambda/StringJoiner.1/webrev/
>>>
>>> StringJoiner
>>> Line 61 example - missing bracket )
>>>
>>> First line of some method descriptions starts with lower case rather
>>> than upper.
>>>
>>> Line 260 exception not listed in Javadoc
>>>
>>> As a general rule, I would try very hard to return a String, not a
>>> CharSequence. Accepting a CharSequence on input is OK, but returning
>>> it gives very few guarantees to callers. Think Postels law.
>>>
>>> Stephen
>>>
>>>
>>
>