Hello, I'm responding to the thread at [1] (I'm not sure whether my message will get appended to it) and the CSR at [2].
I stumbled here from StackOverflow where - indepedently of all the others - I also came up with this type of "dual" *Collector* [3]. I named it "collectingBoth" there but I'd like to suggest a slightly different name here. I believe that Zheka Kozlov made a great observation about similiarity to "collectingAndThen" [4]. And it seems Brian Goetz favors the "AndThen" suffix [5]. On the other hand, this new Collector differs from "collectingAndThen" in that: 1) it hides the accumulation type parameters (A1, A2), and 2) it needs a few lower bounds on some of its type parameters. All in all, I'd like to propose to name the method "collectingBothAndThen" (or alternatively: "biCollectingAndThen". As an aside, I'd like to suggest changing the name of the parameter from "merger" to "biFinisher": 1) Peter Levart pointed out in [6] that "finisher" is already taken by the Collector API (and it's true), but it didn't prevent "collectingAndThen" from taking a "finisher" and then calling: downstream.finisher().andThen(finisher) 2) note that in all other contexts "merger" represents a BinaryOperator because it merges two values of the *same* type, and here the types of merged values are different. Complete signatures for comparison below: *<T,A,R,RR> Collector<T,A,RR> collectingAndThen(* * Collector<T, A, R> downstream,* * Function<R, RR> finisher)* *<T,R1,R2,R> Collector<T,?,R> collectingBothAndThen(* * Collector<? super T, ?, R1> downstream1,* * Collector<? super T, ?, R2> downstream2,* * BiFunction<? super R1, ? super R2, R> biFinisher)* As to the other potential names, I must say: - I'm not in favor of "teeingAndThen" nor all the duplex-related names (I find them unintuitive, especially the "teeing" one), - I really like "composite" and "compound" proposed by Stuart Marks [7]; it seems that "compouding" could be both intuitive and adhering to the -ing suffix convention [1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-August/054718.html [2] https://bugs.openjdk.java.net/browse/JDK-8209685 [3] https://stackoverflow.com/a/52211175/2032415 [4] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-June/053922.html [5] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-August/054736.html [6] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-August/054724.html [7] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-August/054949.html -- Regards, Tomasz Linkowski
