Hi Jim,
Its cleaner to do the API (CSR) review before and without the
implementation.
It helps keep the issues separate.
Don't make statements about count == Integer.MAX_VALUE / 2.
There is no point, unless it should throw IAE.
On 2/15/2018 3:16 PM, Jim Laskey wrote:
On Feb 15, 2018, at 4:04 PM, Remi Forax <fo...@univ-mlv.fr> wrote:
I'm not sure we need 4, it's just a convenient method that may be slower than
if the user code calls toString() (because of profile pollution),
so i'm not sure i pull it's own weight.
And about adding a default method into CharSequence, the default method should
return a CharSequence or String ?
If you mean each class returns an instance of its class, I think that overlaps
Appendable..
Beware thinking about default methods on interfaces; the dragons will
get you.
Recently, this was discussed in the context of Reader.transferTo.
and what about the other implementations, AbstractStringBuilder and CharBuffer
at least ?
This falls into the Appendable.append( T t, int count) realm mentioned
originally.
Long term this could be a goal, and maybe defaulting CharSequence#repeat
returning a string would be shortsighted.
But, I think having instance String#repeat returning a CharSequence would limit
its use (methods expecting strings.)
There is no point in returning CharSequence, a String is a CharSequence
and can be used anywhere
a CharSequence can.
$.02, Roger
— Jim
Rémi
----- Mail original -----
De: "Jim Laskey" <james.las...@oracle.com>
À: "Brian Goetz" <brian.go...@oracle.com>
Cc: "core-libs-dev" <core-libs-dev@openjdk.java.net>
Envoyé: Jeudi 15 Février 2018 18:34:19
Objet: Re: RFR: 8197594 - String and character repeat
Very reasonable approach.
On Feb 15, 2018, at 1:31 PM, Brian Goetz <brian.go...@oracle.com> wrote:
I suggest merging 1 and 4 by making it an instance method on CS with a default
in CS and an override on string and string builder?
Sent from my MacBook Wheel
On Feb 15, 2018, at 9:20 AM, Jim Laskey <james.las...@oracle.com> wrote:
This is a pre-CSR code review [1] for String repeat methods (Enhancement).
The proposal is to introduce four new methods;
1. public String repeat(final int count)
2. public static String repeat(final char ch, final int count)
3. public static String repeat(final int codepoint, final int count)
4. public static String repeat(final CharSequence seq, final int count)
For the sake of transparency, only 1 is necessary, 2-4 are convenience methods.
In the case of 2, “*”.repeat(10) performs as well as String.repeat(‘*’, 10).
3 and 4 convert to String before calling 1.
Performance runs with jmh (results as comment in [2]) show that these
methods are significantly faster that StringBuilder equivalents.
- fewer memory allocations
- fewer char to byte array conversions
- faster pyramid replication vs O(N) copying
I left StringBuilder out of scope. It falls under the category of
Appendables#append with repeat. A much bigger project.
All comments welcome. Especially around the need for convenience
methods, the JavaDoc content and expanding the tests.
— Jim
[1] webrev: http://cr.openjdk.java.net//oj/home/jlaskey/8197594/webrev-00
[2] jbs: https://bugs.openjdk.java.net/browse/JDK-8197594
