Question

I am new into java world.. But basically I am trying to write a user-defined-function in pig-latin.

The following is the relevant code.

public class time extends EvalFunc<String>{

public String exec(Tuple input) throws IOException {

    if ((input == null) || (input.size() == 0))
        return null;
    try{
        String time = (String) input.get(0) ;
        DateFormat df = new SimpleDateFormat("hh:mm:ss.000");
        Date date = df.parse(time);
        String timeOfDay = getTimeOfDay(date);
        return timeOfDay;
    } catch (IOException e) {
        throw e;
    }

}

So basically input is a tuple… I do a check whether the tuple is empty or not..
And then get convert that date string to time object.. and then parse the time part..
and then the function

  getTimeOfDay(date) returns a string... like breakfast, lunch dinner.. or empty string depending on the time hours..

Now the issue is that my eclipse says and error (red line) in

 Date date = df.parse(time);
 String timeOfDay = getTimeOfDay(date);

says

 Unhandled exception type ParseException

But no matter what I try (gives me 3 options.. add catch clause to surrounding try, add exception to existing catch block and surround with try/catch..), the error shifts.. but is always tehre.

And i am not even sure that I can change the structure of program..(the method declaration etc)..

How do I resolve this.

  A quick guide on udf http://wiki.apache.org/pig/UDFManual

If you know pig.. or knows an easy method.. then basically what i am trying to do is .. given an input string of type “time,id,amount” check at what time of the day the transaction was made?

THanks

Answer 1

• If your exec method is already declared to throw IOException, you do not need to catch it and throw it as the throws declaration will automatically do that.
• As for ParseException you have to decide how to handle it.
• Also a bracket was missing =)

So your code should be:

public class time extends EvalFunc<String>{

public String exec(Tuple input) throws IOException {

    if ((input == null) || (input.size() == 0))
        return null;
    try{
        String time = (String) input.get(0) ;
        DateFormat df = new SimpleDateFormat("hh:mm:ss.000");
        Date date = df.parse(time);
        String timeOfDay = getTimeOfDay(date);
        return timeOfDay;
    } catch (ParseException e) {
        //how will I handle when df.parse(time) fails and throws ParseException?
        //maybe:
        return null;
    }
  } //exec

} //class