Entity with field storing filter expressions

[thaingo]

I have a use-case in which api client wants to store a condition in an entity field. The condition is a combination of different filter expressions. At one point in time, the condition will be validated by backend side. If the validation result is true then backend will take some action, otherwise other one.

To leverage Elide and its rsql parser, here is what in my mind for now:

1. The condition is stored as a string and it would be filterParams
2. And the condition supports only filter expression for specific collection types
3. The condition will be validated at runtime or at some scheduled time by backend.

To make the idea happens, I need to have ability to parse the condition (i), convert the condition to, let's say JPQL/HQL (ii), execute the queries and get result (iii), and then check the result to take some action (iv). Could you please advise me, especially item (i) and (ii)?

[aklish]

(i) is done in Elide in the FilterTranslator:
https://github.com/yahoo/elide/blob/master/elide-datastore/elide-datastore-jpql/src/main/java/com/yahoo/elide/datastores/jpql/filter/FilterTranslator.java#L296-L298

This code is used both by JPA and aggregation stores to generate JPQL or SQL from a filter predicate.

(ii) is done in the JPA/JPQL store here:
https://github.com/yahoo/elide/blob/master/elide-datastore/elide-datastore-jpql/src/main/java/com/yahoo/elide/datastores/jpql/query/RootCollectionFetchQueryBuilder.java