Just a quick follow up. I played a bit around with the CasIOUtils, and it seems that it is possible to load and use the embedded type system, i.e. the old type system with X, but I found no way to replace it with the new type system and make the necessary mappings to Y. I tried to see if I could use the CasCopier in a separate step but it expectedly fails when it reaches to the FSArray of X in the source CAS because the destination type system requires elements of type Y. I could make my own modified version of the CasCopier that could take some mapping functions for each pair of source and destination types that need to be mapped, but this is where it starts to get too complicated, so I found it not to be worth it at this point, since we might then want to reprocess everything from scratch anyway.
Cheers, Mario > On 12 Sep 2019, at 10:41 , Mario Juric <[email protected]> wrote: > > Hi, > > We use form 6 compressed binaries to persist the CAS. We now want to make a > change to the type system that is not directly compatible, although in > principle the new type system is really a subset from a data perspective, so > we want to migrate existing binaries to the new type system, but we don’t > know how. The change is as follows: > > In the existing type system we have a type A with a FSArray feature of > element type X, and we want to change X to Y where Y contains a genuine > feature subset of X. This means we basically want to replace X with Y for the > FSArray and ditch a few attributes of X when loading the CAS into the new > type system. > > Had the CAS been stored in JSON this would be trivial by just mapping the > attributes that they have in common, but when I try to load the CAS binary > into the new target type system it chokes with an EOF, so I don’t know if > that is at all possible with a form 6 compressed CAS binary? > > I pocked a bit around in the reference, API and mailing list archive but I > was not able to find anything useful. I can of course keep parallel > attributes for both X and Y and then have a separate step that makes an > explicit conversion/copy, but I prefer to avoid this. I would appreciate any > input to the problem, thanks :) > > Cheers, > Mario > > > > > > > > > > > > >
