Add versioning/migration API about paper HOT 6 CLOSED

@Dosssik you have to make a migration manually: having both classes available in the next version and manually read using the old class to migrate data to the new one. It's like changing the table name in SQL database – you need a migration script.

from paper.

Paper has been designed around the idea that migration is not needed and should be done automatically. Have you met the case when the real migration is still needed?

from paper.

I'm using it as my sole database, which is why I would like the migration.

I'm not asking for migrating a class between versions, but for the migrating the serialized data persisted in a Paper.book() between versions.

from paper.

Yep, makes sense.

from paper.

@pilgr Hi there!
Is it possible to handle following case:

1. We saved some pojo Item in Paper in usual way - Paper.book().write("TABLE_NAME_KEY", item)
2. After some time we decide to move our item from one package to another. E.g. that was com.test.app.firstpackage.Item and become com.test.app.secondpackage.Item
3. If we update our app with new package structure and trying to get saved item from Paper - we getting error:
   Caused by: io.paperdb.PaperDbException: Couldn't read/deserialize file /data/user/0/com.test.app/files/io.paperdb/TABLE_NAME_KEY.pt"

Is there any way to hadle that issue?
Thanks in advance

from paper.

@Dosssik you have to make a migration manually: having both classes available in the next version and manually read using the old class to migrate data to the new one. It's like changing the table name in SQL database – you need a migration script.

Got it, thanks!

from paper.