Persistence layer in codebase

[shyamakirala]

Currently, in the flux codebase, the resource and controller classes interact with DAO layer directly. This lacks good coding practices such as separation of concerns, extensibility, and readability. One way to solve this problem would be to introduce a persistence layer that would handle all the transactions by interacting with DAO layer. The communication would be like below with the new model.

Resource --> Controller --> Persistence Layer --> DAO layer

[regunathb]

I propose to implement this along the lines of JPA i.e. Entities, EntityManager, PersistenceProvider(s) and Criteria with a suitable Query language.