duck-stream-ext.clj

(in-ns 'clojure.contrib.duck-streams)
(import '(java.io File RandomAccessFile))

;; copied and adapted from c.c.ds

(defmulti #^{:arglist '([x])} random-access-reader class)
(defmethod random-access-reader File [#^File x]
  (RandomAccessFile. x "r"))
(defmethod random-access-reader String [#^String x]
  (random-access-reader (file-str x)))
(defmethod random-access-reader :default [x]
  (throw (Exception. (str "Cannot open " (pr-str x) " as a reader."))))

;; causes the problem when eveluated on the repl
; (let [raf (random-access-reader "/Users/angerman/upps.data.model")
;       line (.readLine raf)]
;   nil)

(defmacro with-random-access-reader
  "Opens a RandomAccessFile on f, binds it to *file*, and evaluates body."
  [f & body]
  `(with-open [stream# (random-access-reader ~f)]
     (binding [*raf* stream#]
       ~@body)))