Open Source library for Data validation and Mapping using XML config file

[CompGrmmR]

Hi folks,

I am looking for a way to do validation and data mapping by picking up
the validation rules and mapping rules from an XML config file.

I want to do this so that I dont have to recompile the code if there
are any changes in validation/mapping for the values.

Hence I am looking for some open source utility(like Apache Commons
package)
to do the foll : -

1) Validate a set of data (say from a msg over the n/w) based on the
rules in an XML config file
2) Map this data to a value as specified in an XML config file (i.e to
form a java object with the correct mapped values)

For part 1) there is already Apache Commons Validator, but I cannot
use it for mapping the data to a particular value from an XML config
file..

Could you pls suggest any open source library I could use to
accomplish the above? Also, any other ideas are welcome..

Thanks