----- Mail original ----- > De: "Jim Laskey" <james.las...@oracle.com> > À: "Remi Forax" <fo...@univ-mlv.fr> > Cc: "Brian Goetz" <brian.go...@oracle.com>, "core-libs-dev" > <core-libs-dev@openjdk.java.net> > Envoyé: Jeudi 15 Février 2018 21:16:48 > Objet: Re: RFR: 8197594 - String and character repeat
>> 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.. yes, very true > >> 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.) yes, i think we should play safe here and only add repeat to String. > > — Jim Rémi > >> >> 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
