Why make FieldSet final?

[joeserel]

I am not sure why Spring Batch team make FieldSet final. This decision limits customized formatting. For example, some of my client send Date field as CCYYMMDD. When they do not have a valid date, they put "00000000" and readDate will generate bad results (no exception). I would like to overwrite readDate to handle it correctly.

Also, our client is encoding numbers as IBM numeric so the last digits is symbols like "{", "A", etc. I would like to overwrite readDecimal to handle it correctly.

From design perspective, why not allowing extending FieldSet?

Thanks

[Dave Syer]

I think we can probably allow extensions to FieldSet. It's a tough call when writing frameworks, how much to expose for extension, and traditionally Spring has been rather lax. In this case I can see that it is a pretty useful extension point, and the package is definitely not internal, since it necessarily contains the FieldSetMapper interface. I will change FieldSet to be non-final.

[tonyjoe]

Dave,

Can you also perhaps make FieldSet be an interface rather than a class (and make the current FieldSet be "FieldSetImpl")? Since your docs say this:

A FieldSet is conceptually very similar to a Jdbc Result Set.

this would be more consistent with the ResultSet and [font=courier]RowSet[/courier] which are both interfaces.

There are some other suggestions I have regarding the FieldSet which I hope to post in the next day or so, but I'm finishing up some sample code I'll share with you before I do so.

[joeserel]

Dave,

Thanks for the quick response.

It would be great if you can change indexOf to protected too. It is very useful when trying to extend this class.

I would agree with Tony it makes sense to make it an interface.

[tonyjoe]

I've opened a JIRA for the FieldSet interface...
http://jira.springframework.org/browse/BATCH-289