RFR(s): 8152617 add missing wildcards to Optional or() and flatMap()
stuart.marks at oracle.com
Fri Oct 7 17:20:28 UTC 2016
Please review this small API adjustment to Optional.or and flatMap to add
wildcards. This provides a bit more flexibility to callers about the types of
functions they can provide to these methods.
The or() method is new in 9 so there is no compatibility issue.
The flatMap() method was introduced in 8, so this is a change to an existing
API. There shouldn't be a binary compatibility issue, since the method's erasure
doesn't change. I *think* it is source compatible, as anything that was accepted
by the old signature:
flatMap(Function<? super T, Optional<U>> mapper)
should also be accepted by the new signature:
flatMap(Function<? super T, ? extends Optional<? extends U>> mapper)
But there may be some subtle issues of which I'm unaware.
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