I'm confused on the thread issue. Don't futures run from the agent thread pool? So they don't really create a thread?
Also found climatecorp's claypoole library, which has a 'future' call that works with a thread pool, further confusing me. Not sure how that's different from the agent thread pool. On Saturday, December 6, 2014 1:16:56 PM UTC-8, juan.facorro wrote: > > Hi Brian, > > I had the same requirement while building an application, it included a > GUI and I wanted to perform some actions only after the user was done > editing some text. I also first implemented a solution using an atom, > Thread/sleep and a future. It didn't seem right though, since I was > creating a bunch of threads all the time, so I tried an approach with the > tools core.async provides and the result was the following: > > (defn timeout-channel > "Creates a channel and a go block that takes from it. The go block keeps > an internal status with two possible values, `:wait` and `:receive`. > In ':wait' status, execution is blocked until there's a value available in the > channel, it then enters the ':receive' status, until the timeout wins. > Returns the channel where events need to be pushed." > [timeout-ms f] > (let [c (async/chan)] > (async/go-loop [status :wait > args nil] > (condp = status > :wait > (recur :receive (async/<! c)) > :receive > (let [[_ ch] (async/alts! [c (async/timeout timeout-ms)])] > (if (= ch c) > (recur :receive args) > (do > (async/thread (if (sequential? args) (apply f args) (f args))) > (recur :wait nil)))))) > > c)) > > Signalling the go block to terminate when the event source is no longer > available is missing, but that simple enough to implement. Maybe this is > something you can use as a starter point. > > Hope it helps, > > Juan > > > > On Monday, December 1, 2014 6:37:56 PM UTC-3, Brian Craft wrote: >> >> I have need to perform an action when a series of events is quiet for >> some period. That is, if one event arrives an action is queued to execute >> after some timeout. If a second event arrives the timeout is reset, and >> so-forth. >> >> The following code seems to work, however I'm wondering if calling >> 'future' from 'swap!' is a bad idea (side effecting), and if there's a >> better way. >> >> (defn queue-with-delay [period func] >> (let [f (atom nil)] >> (fn [] >> (when @f >> (future-cancel @f)) >> (swap! f (fn [_] (future (Thread/sleep period) (func))))))) >> >> >> Use like >> >> (def event (queue-with-delay 2000 #(println "running"))) >> (event) >> (event) >> (event) ; pause 2 sec >> "running" >> >> >> >> -- 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.
