@Override
    protected Short generateRandomNonNullValue(Random rand) {
      return (short) (rand.nextInt((Short.MAX_VALUE - Short.MIN_VALUE) / 2)
          + (Short.MIN_VALUE / 2));
    }
Base class for type specific batch generators. Each type specific batch generator implements
generateRandomNonNullValue to generate random values, and initializeFixedPointValues to
specify a set of fixed values within the data (this is useful when defining query predicates)
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/util/OrcFileGenerator.java