RFR - JDK-8203442 String::transform (Code Review)

Jim Laskey james.laskey at oracle.com
Wed Sep 19 13:35:49 UTC 2018

> On Sep 19, 2018, at 9:58 AM, Remi Forax <forax at univ-mlv.fr> wrote:
> Hi Jim,
> the signature of transform() in the webrev was not updated (so the wildcards are missing).

Apologies.  I created the webrev before I fully saved. Will update in a bit.

> And i'm still not convince this method should be introduced as is:
> - it need more variants (transformToInt, transformToLong, transformToDouble) to be useful, currently "foo".transform(String::length) do box the resulting int to an Integer.
> - pull it's own weight, while it's nice to be able to be able to write code fluently from left to right, "foo".transform(Utils::capitalizeFirstLetter), you can say exactly the same thing for all classes in the JDK, e.g. path.transform(Utils.appendTextSuffix). Other languages have introduced an operator to solve that issue (function call syntax is not fluent) like by example the operator '|>' as in "foo" |> Utils.capitalizeFirstLetter.

I hear you. Wouldn’t it be nice to have an Object::transform. Won't happen since it would likely break the world. You could push for something |> method(…) which applies static R method(T fakeThis, …), but that will take years of debate.  String::transform was intended to facilitate custom manipulation (alignment) of raw string literals, in the most string generalized way. I’ll  discuss the other variants but please provide better use cases.


— Jim

> regards,
> Rémi
> ----- Mail original -----
>> De: "Jim Laskey" <james.laskey at oracle.com>
>> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
>> Envoyé: Mardi 18 Septembre 2018 19:52:17
>> Objet: RFR - JDK-8203442 String::transform (Code Review)
>> Please review the code for String::transform. The goal is to provide a String
>> instance method to allow function application of custom transformations applied
>> to an instance of String.
>> webrev: http://cr.openjdk.java.net/~jlaskey/8203442/webrev/index.html
>> jbs: https://bugs.openjdk.java.net/browse/JDK-8203442
>> csr: https://bugs.openjdk.java.net/browse/JDK-8203703
>> Cheers,
>> — Jim

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