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https://issues.apache.org/jira/browse/EDGENT-393?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dale LaBossiere updated EDGENT-393:
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Summary: Wish for Ranges.outsideOf() (was: Wish for Functions.not())
> Wish for Ranges.outsideOf()
> ---------------------------
>
> Key: EDGENT-393
> URL: https://issues.apache.org/jira/browse/EDGENT-393
> Project: Edgent
> Issue Type: Wish
> Components: API
> Reporter: Dale LaBossiere
> Priority: Minor
>
> I want to be able to write something like:
> {code}
> TStream ...
> .filter(Functions.not(Ranges.closed(100,200))) // true if outside
> [100..200]
> {code}
> The above creates only a single Range and single "not" predicate at topology
> construction time.
> If I made the following mistake I'd create a Range for every tuple:
> {code}
> TStream ...
> .filter(t -> ! Ranges.closed(100,200).contains(t))
> {code}
> In the absence of a "not" Predicate like approach I'd have to explicitly
> allocate my range outside of the lambda:
> {code}
> Range myRange = Ranges.closed(100,200);
> TStream ...
> .filter(t -> ! myRange.contains(t))
> {code}
> The implementation of "not" is trivial and seems like it might be useful in
> other cases:
> {code}
> static <T> Predicate<T> not(Predicate<T> predicate) {
> return t -> ! predicate.test(t);
> }
> {code}
> Yes, I'd be trading off an additional {{Predicate.test()}} invocation per
> tuple against the "out of line" myRange instantiation approach. But I'd get
> to choose which was more important to me.
> Thoughts?
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