I don't think we need to enforce the use of Optional (at least not to begin with), but it would be a good idea to use it in new code.
On Fri, Oct 11, 2019 at 6:35 AM Jad Naous <jad.na...@imply.io> wrote: > On using Optional: to me, it was mostly a documentation issue, making it > easier to no longer have to worry about whether some method will return > null or whether someone will pass null to a method. It also made it easier > to remember to actually check for the existence of something before using > it. We also used Guava's Optional which is much more pleasant to work with > than the JDK's Optional. > > On Thu, Oct 10, 2019 at 5:46 PM Gian Merlino <g...@apache.org> wrote: > >> For reference, a (brief) earlier conversation about this: >> https://github.com/apache/incubator-druid/issues/4275, which links to >> https://github.com/apache/incubator-druid/pull/4254#discussion_r116628607 >> , >> which links to >> >> https://stackoverflow.com/questions/26327957/should-java-8-getters-return-optional-type/26328555#26328555 >> . >> >> I really enjoyed programming with Scala's Option type, back when I had >> spend a couple of years writing Scala code. They are awesome. Java >> Optionals are sadly not quite as good, especially in ecosystem support >> (they're not adopted very well in libraries or in the jdk itself) but also >> in functionality (in Scala they're tightly integrated into the collections >> library, which allows for some nice idioms). >> >> After that Scala break, when I came back to Java I wrote a lot of the >> indexing service module. You can tell because it has Guava Optionals >> everywhere. I mostly used it the way that Goetz recommended, as a method >> return type in commonly used interfaces or utility methods. It was a bit >> clunky but it was overall nice. I don't regret it. But now I mostly don't >> use them anymore, and started using null-returns (with @Nullable >> annotations) instead since it jives better with the rest of the codebase. >> >> Jad, or anyone else, have you worked on Java codebases where Optional was >> heavily used? What was the experience like? >> >> Also, has anyone had experience introducing a preference for Optionals >> into >> a large pre-existing codebase? >> >> On Wed, Oct 9, 2019 at 12:46 PM Jad Naous <jad.na...@imply.io> wrote: >> >> > Sir Tony Hoare on inventing null while working on ALGOL (from wikipedia >> > below): >> > >> > Speaking at a software conference called QCon London >> > <https://qconlondon.com/> in 2009, he apologised for inventing the null >> > reference <https://en.wikipedia.org/wiki/Null_pointer>:[23] >> > <https://en.wikipedia.org/wiki/Tony_Hoare#cite_note-23> >> > >> > I call it my billion-dollar mistake. It was the invention of the null >> > reference in 1965. At that time, I was designing the first comprehensive >> > type system for references in an object oriented language (ALGOL W >> > <https://en.wikipedia.org/wiki/ALGOL_W>). My goal was to ensure that >> all >> > use of references should be absolutely safe, with checking performed >> > automatically by the compiler. But I couldn't resist the temptation to >> put >> > in a null reference, simply because it was so easy to implement. This >> has >> > led to innumerable errors, vulnerabilities, and system crashes, which >> have >> > probably caused a billion dollars of pain and damage in the last forty >> > years. >> > >> > How about we stop passing nulls around as method arguments, field >> values, >> > return values, etc and use Optional instead? Benefits: >> > - No more NPEs >> > - Better documentation through code >> > - Less mistakes >> > >> > I'm not suggesting we go rewrite everything, but rather just starting to >> > only return and accept Optionals in methods/constructors/etc. >> > >> > Jad. >> > >> > -- >> > Jad Naous >> > Imply | VP R&D >> > 650-521-3425 >> > jad.na...@imply.io >> > >> > > > -- > Jad Naous > Imply | VP R&D > 650-521-3425 > jad.na...@imply.io > -- Jad Naous Imply | VP R&D 650-521-3425 jad.na...@imply.io
