Could you please prototype what you suggest in code so we could discuss it more
constructively? Otherwise I feel this discussion is getting too broad and as
such may not achieve anything in particular.
Thanks,
-Pavel
> On 30 Jul 2016, at 10:03, Fabian Lange <lange.fab...@gmail.com> wrote:
>
> Hi,
> so why did you guys invent CharSequence as an API if it cannot be used.
> I kind of understand why people use unsafe and come up with their own
> character data implementations.
>
> So you prefer multi megabyte string allocations including their arraycopy,
> (java.lang.StringBuilder.toString())
>
> public String toString() {
> // Create a copy, don't share the array
> return new String(value, 0, count);
> }
>
> which then will arraycopy again this multimegabyte char array
> java.io.Writer.write(String, int, int)
>
> } else { // Don't permanently allocate very large buffers.
> cbuf = new char[len];
> }
> str.getChars(off, (off + len), cbuf, 0);
> write(cbuf, 0, len);
>
> over an Implementation which doesn't do that?
>
> Fabian
>
> On Sat, Jul 30, 2016 at 1:23 AM, Brent Christian
> <brent.christ...@oracle.com> wrote:
>> Hi,
>>
>> This idea has been brought up before [1].
>>
>> I concur with Pavel's assessment. I would add that now that latin-1 Strings
>> are stored in a more compact form in JDK 9 ("Compact Strings" [2]), the
>> performance profile of string data is further complicated.
>>
>> Thanks,
>> -Brent
>>
>> 1. https://bugs.openjdk.java.net/browse/JDK-6206838
>> 2. https://bugs.openjdk.java.net/browse/JDK-8054307
>>
>> On 07/29/2016 10:21 AM, Pavel Rappo wrote:
>>>
>>> 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
>>>
>>>
>>
