> 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.. > 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.) — 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 >>>>
