Pig Java UDF Issue

Question

Here is UDF code

package myudf;
import java.io.IOException; 
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.pig.EvalFunc; 
import org.apache.pig.data.Tuple; 

public class DateFormat extends EvalFunc<String> {
    public String exec(Tuple input) throws IOException {
        if (input == null || input.size() == 0) {
            return null;
        }

        try {
            String dateStr = (String)input.get(0);
            SimpleDateFormat readFormat = new SimpleDateFormat( "MM/dd/yyyy hh:mm:ss.SSS aa");
            SimpleDateFormat writeFormat = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss.SSS");
            Date date = null;
            try {
                date = readFormat.parse(dateStr);
            } catch (ParseException e) {
                e.printStackTrace();
            }

            return writeFormat.format(date).toString();
        } catch(Exception e) {
            throw new IOException("Caught exception processing input row ", e);
        }
    }
}

Exported a Jar of this and registered in grunt

    Register /local/path/to/UDFDate.jar;
    A = LOAD 'hdfs date file';
    B = FOREACH A GENERATE UDFDate.myudf.DateFormat($0);

Gives Error

[main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1070: Could not resolve UDFDate.DateFormat using imports: [, java.lang., org.apache.pig.builtin., org.apache.pig.impl.builtin.]

Answer 1

you don't need to specify jar name (UDFDate.myudf.DateFormat) to call function in jar. it should be "packageName.className" (myudf.DateFormat).

---

if DateFormat is in myudf package then you should be running as:

B = FOREACH A GENERATE myudf.DateFormat($0);

---

if DateFormat is in default package then you should be running as:

B = FOREACH A GENERATE DateFormat($0);

Answer 2

call your udf as:

packagename.classname($0);

Answer 3

Answer have been given already but in order basically not to re-define UDF call every time you can simplify it:

Register /local/path/to/UDFDate.jar;
DEFINE myDateFormat myudf.DateFormat();
A = LOAD 'hdfs date file';
B = FOREACH A GENERATE myDateFormat($0);