Your first implementation probably failed because map is lazy, so none of the '.write' calls happened during the with-open block. Try doseq.
On Friday, October 31, 2014 1:08:01 PM UTC-7, Sam Raker wrote: > > I'm writing some stuff to interact with the Twitter API. I want to be able > to write tweets (as JSON) to a file, so I can, e.g., test things without > connecting to the API. I've proxied the LinkedBlockingQueue that Twitter's > HBC library uses to use an agent, so ideally I want to be able to write the > contents of the agent AND the LBQ. Here's what I have right now: > > (defmulti write-tweets (fn [q f] (class q))) > (defmethod write-tweets clojure.lang.Agent [a f] > (with-open [w (clojure.java.io/writer f :append true)] > (.write w (apply str (interpose "\n" @a))))) > (defmethod write-tweets java.util.concurrent.LinkedBlockingQueue [lbq f] > (loop [res (.take lbq)] > (if res > (recur > (with-open [w (clojure.java.io/writer f :append true)] > (.write w (str (generate-string res) "\n"))))))) > > My first implementation of this used `(map #(.write w %) @a)` and had the > `recur` within the `with-open` block. Unfortunately, at least with the > agent part, I ran into an error about the file being closed when I tried to > write to it. I assumed `with-open` kept the file open within the block, but > maybe I'm missing something? I'm worried about the performance of either > creating a potentially super-huge string in memory for the agent method > (twitter returns pretty sizable JSON blobs) or repeatedly opening/closing a > file for the LBQ method (I realize I could collapse this into one problem > by taking everything out of the LBQ and putting it into an agent, but > that's not really a solution...) > > Does `writer` auto-close the file after it's done? Is there some better > way of handling this kind of situation? > -- 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.
