Validator class that looks for file references in the PDS4 product label
and performs the following checks:
- Verify that the generated checksum matches the supplied checksum,
if provided
- Verify that the casing of the file reference matches the file name
casing on the file system
Returns the preference for whether the literal system
identifier should be used when resolving system
identifiers when both it and the expanded system
identifier are available.
Sets the preference for whether the literal system
identifier should be used when resolving system
identifiers when both it and the expanded system
identifier are available.