private static HCatSchema getOutputSchema(Configuration conf)
    throws IOException {
    String os = conf.get(HCatConstants.HCAT_KEY_OUTPUT_SCHEMA);
    if (os == null) {
      return getTableSchema(conf);
    } else {
      return (HCatSchema) HCatUtil.deserialize(os);
    }
  }
get the schema for the HCatRecord data returned by HCatInputFormat.

@param context the jobContext
@throws IllegalArgumentException
hcatalog/core/src/main/java/org/apache/hive/hcatalog/mapreduce/HCatBaseInputFormat.java