code: private Path[] getMapFiles(FileSystem fs, boolean isLocal)
    throws IOException {
      List<Path> fileList = new ArrayList<Path>();
      if (isLocal) {
        // for local jobs
        for(int i = 0; i < numMaps; ++i) {
          fileList.add(mapOutputFile.getInputFile(i, getTaskID()));
        }
      } else {
        // for non local jobs
        for (FileStatus filestatus : mapOutputFilesOnDisk) {
          fileList.add(filestatus.getPath());
        }
      }
      return fileList.toArray(new Path[0]);
    }
docs: Get the input files for the reducer.