[PIG-745] Please add DataTypes.toString() conversion function

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.3.0
• Assignee: David Ciemiewicz
• Reporter: David Ciemiewicz
• Created: 01/Apr/09 20:44
• Updated: 24/Mar/10 22:10
• Resolved: 08/Apr/09 22:00

Description

I'm doing some work in string manipulation UDFs and I've found that it would be very convenient if I could always convert the argument to a chararray (internally a Java String).

For example TOLOWERCASE(arg) shouldn't really care whether arg is a bytearray, chararray, int, long, double, or float, it should be treated as a string and operated on.

The simplest and most foolproof method would be if the DataTypes added a static function of DataTypes.toString which did all of the argument type checking and provided consistent translation.

I believe that this function might be coded as:

public static String toString(Object o) throws ExecException {
try {
switch (findType(o))

{ case BOOLEAN: if (((Boolean)o) == true) return new String('1'); else return new String('0'); case BYTE: return ((Byte)o).toString(); case INTEGER: return ((Integer)o).toString(); case LONG: return ((Long)o).toString(); case FLOAT: return ((Float)o).toString(); case DOUBLE: return ((Double)o).toString(); case BYTEARRAY: return ((DataByteArray)o).toString(); case CHARARRAY: return (String)o; case NULL: return null; case MAP: case TUPLE: case BAG: case UNKNOWN: default: int errCode = 1071; String msg = "Cannot convert a " + findTypeName(o) + " to an String"; throw new ExecException(msg, errCode, PigException.INPUT); }

} catch (ExecException ee)

{ throw ee; }

catch (Exception e)

{ int errCode = 2054; String msg = "Internal error. Could not convert " + o + " to String."; throw new ExecException(msg, errCode, PigException.BUG); }

}