As mentioned in the javadoc for FieldSet, this interface is the file-equivalent of the jdbc ResultSet. spring-batch provides a mapper interface -FieldSetMapper- for mapping the FieldSet to an object, in the same way as spring-jdbc provides a RowMapper interface used to map a ResultSet to an Object.

This equivalence is very useful and makes sense, but I would appreciate to receive the line number as a parameter to the method, in the same way spring-jdbc does for its RowMapper interface:

public interface FieldSetMapper {

/**
* Method used to map data obtained from a file into an object.
*/
public Object mapLine(FieldSet fs, int lineNum);
}


In FlatFileItemReader :
public Object read() throws Exception {
String line = readLine();

if (line != null) {
int lineCount = getReader().getPosition();
try {
FieldSet tokenizedLine = tokenizer.tokenize(line);
return fieldSetMapper.mapLine(tokenizedLine, lineCount);
}
catch (RuntimeException ex) {
throw new FlatFileParseException("Parsing error at line: " + lineCount + " in resource="
+ resource.getDescription() + ", input=[" + line + "]", ex, line, lineCount);
}
}
return null;
}

I need the line number in order to create the object that is mapped to the FieldSet. There is no way to do this except by creating my own FieldSetMapper interface and use it in my own FlatFileItemReader implementation, that overrides your FlatFileItemReader's read() method.