I suspect the problem is with map which is lazy. If you discard the result of the top-level expression it might not be fully completed or not even run at all.
To force a lazy collection (thus, triggering the side effects you desire) you could do the following things: (mapv close pages) ;; mapv returns a vector, thus is eager (dorun (map close pages)) ;; dorun walks the lazy collection and forces the side effects (run! close pages) ;; run! is like map for side effects - preferred in this case On Monday, September 3, 2018 at 5:44:38 AM UTC+3, aboy021 wrote: > > I have a problem related to disposing of resources. > > I’m trying to retrieve portions of pdf files and combine them into a new > pdf file. I’m using Apache PDFBox for the purpose. > Splitting a pdf into pages creates a PDDocument for each page, and > PDDocuments need to be explicitly closed. If you do not, there’s a log > message that comes from the finalizer “Warning: You did not close a PDF > Document”. > > I’ve prepared some naive code that demonstrates the problem. Here I’m > splitting a pdf and recombining it. When the finalizer eventually runs > every page in the pdf seems to produce an error message. > > [org.apache.pdfbox/pdfbox "2.0.11"] > > (import '[org.apache.pdfbox.multipdf PDFMergerUtility])(import > '[org.apache.pdfbox.multipdf Splitter])(import '[org.apache.pdfbox.pdmodel > PDDocument]) > (let [pdf (PDDocument/load (File. "input.pdf")) > splitter (Splitter.) > pages (into [] (.split splitter pdf)) > merger (PDFMergerUtility.) > append (fn [x y] (.appendDocument merger x y) x) > close #(when % (.close %))] > (try > (-> (reduce append (first pages) (rest pages)) > (.save "output.pdf") > (close)) > (finally > (close pdf) > (map close pages)))) > > Any help would be appreciated. > > Also, are there any good resources online for best practice in dealing > with sequences of disposables? > > Thanks, > > Arthur > > -- 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.
