Request for Review: CR#8001667, second attempt (original) (raw)

Peter Levart peter.levart at gmail.com
Fri Dec 7 09:09:18 UTC 2012

Hi Henry,

I don't know what the plans are about moving the static methods in Comparators to the Comparator interface when static interface methods are enabled, but if that is planned, there will be a clash between Comparator.reverseOrder() default method and static method with same name and signature.

Maybe rename static .reverseOrder() to .reverseNaturalOrder() (to long?), or rename the default method .reverseOrder() to .reverse();

Also, I like the natural-language-like fluent syntax when starting with Comparators.comparing(...).thenComparing(...).reverseOrder, but the .thenComparing name is also overloaded with the variant for composing: .thenComparing(Comparator) which makes statements like:

Comparators.comparing(x -> x.size).thenComparing(x -> x.y).thenComparing((x, y) -> some expression)

a little confusing, because what you get is not a comparator that compares one value of "some expression" with some other value of the same expression, but a comparator that uses the value of expression to order two elements.

I think that using the same method name for two different purposes is a little confusing. Maybe .compose(Comparator) or just plain .then(Comparator) would be better here.

Regards, Peter

On 12/06/2012 07:57 AM, Henry Jen wrote:

Hi,

This update reflect changes based on feedbacks for last version, the changes are - rename reverse() to reverseOrder() - rename Comparator.compose to Comparator.thenComparing - add 4 Comparator.thenComparing methods take [Int|Long|Double]Function to enable fluent syntax like this example, people.sort(Comparators.comparing(People::getFirstName).thenComparing(People.getLastName)) vs previously, people.sort(Comparators.comparing(Person::getName)) Comparator byLastFirst = Comparators.comparing(Person::getLastName) .compose(Comparators.comparing(Person::getFirstName)) Please review and comment on the webrev[1] and specdiff[2]. [1] http://cr.openjdk.java.net/~henryjen/ccc/8001667.1/webrev [2] http://cr.openjdk.java.net/~henryjen/ccc/8001667.1/specdiff/overview-summary.html Cheers, Henry

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