Sorted!
Thank you.
On Monday, 3 September 2018 17:32:15 UTC+12, Alexander Yakushev wrote:
>
> 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
>>
>>
>
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