code: public static PathFilter getInputPathFilter(JobContext context) {
      Configuration conf = context.getConfiguration();
      Class<?> filterClass = conf.getClass("mapred.input.pathFilter.class", null,
          PathFilter.class);
      return (filterClass != null) ?
          (PathFilter) ReflectionUtils.newInstance(filterClass, conf) : null;
    }
docs: Get a PathFilter instance of the filter set for the input paths.
  
  @return the PathFilter instance set for the job, NULL if none has been set.