Proxying InputStream

(let [reader (SequenceFile$Reader. file-system x hadoop-conf)
              key (ReflectionUtils/newInstance (.. reader
                                                   getKeyClass
                                                   (asSubclass WritableComparable))
                                               hadoop-conf)
              value (ReflectionUtils/newInstance (.. reader
                                                     getValueClass
                                                     (asSubclass Writable))
                                                 hadoop-conf)
              inbuf (DataInputBuffer.)
              outbuf (DataOutputBuffer.)]
          (. stream close)
          (proxy [InputStream] []
            (read []
              (if (or (nil? inbuf) (= (. inbuf read) -1))
                (if (not (. reader (next key value)))
                  -1
                  (do
                    (let [tmp (.. key toString getBytes)]
                      (doto outbuf
                        (.write tmp 0 (. tmp length))
                        (.write \tab)))
                    (let [tmp (.. value toString getBytes)]
                      (doto outbuf
                        (.write tmp 0 (. tmp length))
                        (.write \newline)))
                    (. inbuf (reset (. outbuf getData)
                                    (. outbuf getLength)))
                    (. outbuf reset)
                    (. read inbuf)))))))