Pass a vector/inputstream to a clojure function via java/scala

Question

I need to call a clojure-function from java/scala which expects a vector or an inputstream as its first argument.

Doing so always yields the following exception:

Execution exception[[UnsupportedOperationException: pdf (clj-pdf.main/-pdf not defined?)]]

I am using clj-pdf and need to call the pdf-function

(defn pdf
  "usage:
   in can be either a vector containing the document or an input stream. If in is an input stream then the forms will be read sequentially from it.
   out can be either a string, in which case it's treated as a file name, or an output stream.
   NOTE: using the :pages option will cause the complete document to reside in memory as it will need to be post processed."
  [in out]
  (if (instance? InputStream in)
    (stream-doc in out)
    (write-doc in out)))

I have modified the source, built a jar via

leiningen uberjar

The modifications to cjl-pdf's project.clj can be seen in the last 2 lines:

(defproject clj-pdf 
  "1.0.6"
  :description "PDF generation library"
  :url "https://github.com/yogthos/clj-pdf"
  :license {:name "GNU Lesser General Public License - v 3"
            :url "http://www.gnu.org/licenses/lgpl.html"
            :distribution :repo
            :comments "same as  iText and JFreeChart"}
  :dependencies [[org.clojure/clojure "1.5.0"]
                 [jfree/jfreechart "1.0.13"]                 
                 [itext-min "0.2"]]

  :aot [clj-pdf.main]
  :main clj-pdf.main)

and in my added main.clj:

(ns clj-pdf.main
  (:gen-class
   ;; neither java.io.InputStream nor ArrayList work:
   :methods [#^{:static true} [pdf [java.util.ArrayList, java.io.OutputStream] void]])
  (:use clj-pdf.core))

(defn -main [& args])

I am using the lib from my scala code as follows:

val output = new ByteArrayOutputStream()
val list = new java.util.ArrayList[String]
list.add( """[:list {:roman true} 
             [:chunk {:style :bold} "a bold item"] "another item" "yet another item"]
             [:phrase "some text"]                                   
             [:paragraph "yet more text"]]""")

clj_pdf.main.pdf(list, output)

Is there any way to get around this?

Answer 1

It works from Java:

    java.util.ArrayList a = new java.util.ArrayList();
    java.io.ByteArrayOutputStream b = new java.io.ByteArrayOutputStream();
    clj_pdf.main.pdf (a, b);

if I add to main.clj:

 (defn -pdf [in out] (pdf in out))

And use the lein uberjar to build the project.

Another alternative is to use the clojure.lang.RT as per https://stackoverflow.com/a/6410926/151650