@Override
  public VectorExpressionDescriptor.Descriptor getDescriptor() {
    return (new VectorExpressionDescriptor.Builder()).setMode(
        VectorExpressionDescriptor.Mode.PROJECTION).setNumArguments(1).setInputExpressionTypes(
            VectorExpressionDescriptor.InputExpressionType.COLUMN).setArgumentTypes(
                VectorExpressionDescriptor.ArgumentType.INT_FAMILY).build();
  }
Superclass to support vectorized functions that take a long
and return a string, optionally with additional configuraiton arguments.
Used for bin(long), hex(long) etc.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/FuncLongToString.java