So if I'd need that extra performance, say in a private library of transducers not intended to be shared with other Clojure developers, it is perfectly Ok to use a java.lang.Object instead of a volatile, right ?
J 2015-01-02 15:59 GMT+01:00 Timothy Baldridge <tbaldri...@gmail.com>: > "As far as I understand, the step-function of a transducer is never(?) > accessed concurrently by more than 1 thread." > > It's actually "one thread at a time". And you're right, stuff like > Core.async may bounce a transducer between several different threads, but > only 1 thread "owns" it at a given time. > > Timothy > > On Fri, Jan 2, 2015 at 7:11 AM, Jörg Winter <jwin1...@gmail.com> wrote: > >> Hi, >> >> As seen in this example of a stateful transducer... >> >> http://crossclj.info/ns/org.clojure/clojure/latest/clojure.core.html#_partition-by >> >> ... I am wondering what is the concrete motivation behind using >> 'volatile!' instead of say a simple (mutable) Java-Object wrapper ? >> In the partition-all example, an ArrayList is used for aggregating the >> 'temporary' results for the step-function, so this mutable state is not >> concerned with threading at all. >> Why then is there a threading-concern with pv (the volatile!) ? >> >> As far as I understand, the step-function of a transducer is never(?) >> accessed concurrently by more than 1 thread. >> >> Is volatile! necessary because transducers should be usable with >> core.async ? >> Or is it just an easy way to get a mutable object in Clojure ? >> >> >> Best, >> Joerg >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clojure@googlegroups.com >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+unsubscr...@googlegroups.com >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to clojure+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > “One of the main causes of the fall of the Roman Empire was that–lacking > zero–they had no way to indicate successful termination of their C > programs.” > (Robert Firth) > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to a topic in the > Google Groups "Clojure" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/clojure/CjxK7xEsOKQ/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > clojure+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
