Once again, while I agree in some places it could have been done a bit better
probably, I would say it's good to a have a look at benchmarks first.
If they show there's indeed a big difference between
char[] copy = new chars[charSequence.length()];
String s = charSequence.toString();
s.getChars(0, s.length, copy, 0);
and
char[] copy = new chars[charSequence.length()];
charSequence.getChars(0, charSequence.length(), copy, 0);
it could justify an increase in complexity of CharBuffer.append or introducing a
new default method (getChars/fillInto) into CharSequence. Possibly. Or maybe
not. Because there might be some nontrivial effects we are completely unaware
of.
Btw, what do you mean by "extract char[]" from StringBuilder? Do you want
StringBuilder to give away a reference to its char[] outside? If not, than
what's the difference between "extract char[]" from StringBuilder and "use
String" in your algorithm?
The bottom line is whatever you suggest would likely need a good justification.
To me it's not immediately obvious that something like this
public CharBuffer append(CharSequence csq) {
if (csq == null) {
put("null");
} else if (csq instanceof StringBuilder) {
char[] chars = new char[csq.length()];
((StringBuilder) csq).getChars(0, csq.length(), chars, 0);
put(chars);
} else if (csq instanceof StringBuffer) {
char[] chars = new char[csq.length()];
((StringBuffer) csq).getChars(0, csq.length(), chars, 0);
put(chars);
} else if (csq instanceof CharBuffer) {
CharBuffer buffer = (CharBuffer) csq;
int p = buffer.position();
put(buffer);
buffer.position(p);
} else {
for (int i = 0; i < csq.length(); i++) {
put(csq.charAt(i));
}
}
return this;
}
is better than this (what's there today)
public CharBuffer append(CharSequence csq) {
if (csq == null)
return put("null");
else
return put(csq.toString());
}
> On 29 Jul 2016, at 15:12, e...@zusammenkunft.net wrote:
>
> Hello,
>
> Have to agree with Fabian handling CharSequences (and special case
> StringBuilder) is pretty weak, in CharBuffer.append(CharSequence) you see the
> same toString. I would expect it to do:
> - Instamceof String -> use it
> - Instance of StringBuilder -> extract char[] and iterate
> - Instance of CharBuffer -> handle
> - Otherwise: Loop over charAt
>
> (the otherwise might be a tradeof between allocation and (not)inlined bounds
> checks)
>
> Alternative would be a CharSequence.fillInto(char[])
>
> BTW wouldn't it be create if char[] implements CharSequence?
>
> Gruss
> Bernd
> --
> http://bernd.eckenfels.net
> From Win 10 Mobile
>
> Von: Fabian Lange
