Hmm, wrong link? Iterator contract doesn't require hasNext() to be called compared to beam (even if it is highly recommanded). Aligned on beam it means the runner can acll getCurrent() without calling start or advanced and consider it is done if there is a NSEE which will likely never works since start/advance bufferizes current in most (all?) impl. So it is likely a bit different.
To be concrete iterator often handle hasNext implicitly in next() if needed whereas beam IOs never do it. Romain Manni-Bucau @rmannibucau <https://twitter.com/rmannibucau> | Blog <https://rmannibucau.metawerx.net/> | Old Blog <http://rmannibucau.wordpress.com> | Github <https://github.com/rmannibucau> | LinkedIn <https://www.linkedin.com/in/rmannibucau> | Book <https://www.packtpub.com/application-development/java-ee-8-high-performance> 2018-03-12 17:35 GMT+01:00 Thomas Groh <tg...@google.com>: > The correct sequencing and respecting return values of `start` and > `advance` is a precondition, and `NoSuchElementException` is the failure > mode if the precondition isn't met. Documenting the behavior in the case of > precondition failures is entirely reasonable. For example, look at Java's > `Iterator` documentation, which has basically the same text: > https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html > > > On Mon, Mar 12, 2018 at 9:20 AM Romain Manni-Bucau <rmannibu...@gmail.com> > wrote: > >> I agree Thomas but I kind of read it as "yes we can drop that >> constraint". If not we should also check we are used in a thread safe >> context etc which will likely never hit the user sdk API so why doing that >> case a particular case? Am I missing something? >> >> >> Romain Manni-Bucau >> @rmannibucau <https://twitter.com/rmannibucau> | Blog >> <https://rmannibucau.metawerx.net/> | Old Blog >> <http://rmannibucau.wordpress.com> | Github >> <https://github.com/rmannibucau> | LinkedIn >> <https://www.linkedin.com/in/rmannibucau> | Book >> <https://www.packtpub.com/application-development/java-ee-8-high-performance> >> >> 2018-03-12 17:04 GMT+01:00 Thomas Groh <tg...@google.com>: >> >>> If a call to `getCurrentWhatever` happens after `start` or `advance` has >>> returned false, it's a bug in the runner, but the reader needs to be able >>> to fail, otherwise you'll get a synthetic element that doesn't really >>> exist. If a reader throws `NoSuchElementException` after the most recent >>> call returned true, the reader isn't conforming to spec. >>> >>> >>> On Mon, Mar 12, 2018 at 9:00 AM Romain Manni-Bucau < >>> rmannibu...@gmail.com> wrote: >>> >>>> Hi guys, >>>> >>>> why reader#getCurrent* can throw NoSuchElementException, >>>> my understanding is that the runner will guarantee that start or >>>> advance was called and returned true when calling getCurrent so this is a >>>> case which shouldn't happen, no? >>>> >>>> Romain Manni-Bucau >>>> @rmannibucau <https://twitter.com/rmannibucau> | Blog >>>> <https://rmannibucau.metawerx.net/> | Old Blog >>>> <http://rmannibucau.wordpress.com> | Github >>>> <https://github.com/rmannibucau> | LinkedIn >>>> <https://www.linkedin.com/in/rmannibucau> | Book >>>> <https://www.packtpub.com/application-development/java-ee-8-high-performance> >>>> >>> >>
