@Override
  public String vectorExpressionParameters() {
    return getColumnParamString(0, inputColumnNum[0]);
  }
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