models.md

Models

Javarel currently supports JPA for persisting data in database. Supported database systems are: Derby Embedded (default), MySQL, PostreSQL.

Database admin

To retrieve or update your data use DatabaseAdmin service.

@Path("/user")
class UserController {

    @Uses
    private lateinit var db: DatabaseAdmin

    @GET
    @Path("/create")
    @Produces(MediaType.APPLICATION_JSON)
    fun getCreate(): User {
        return dbAdmin.session { em ->
            val repo = UserRepository(em)
            val user = User("[email protected]", "qwerty")

            repo.save(user)

            return@session user
        }
    }

    @GET
    @Path("/list")
    @Produces(MediaType.APPLICATION_JSON)
    fun getList(): List<User> {
        return dbAdmin.session { em ->
            val repo = UserRepository(em)
            val users = repo.findAll()

            return@session users.toList()
        }
    }
}

Multiple databases can be used in one application. Just define named connections in OSGi configuration (Javarel Storage - ... Connection). Then you can write:

dbAdmin.session("pgsql" { em ->
    // ...
}

Repositories

To simplify CRUD operations while operating on domain model, just extend DomainRepository (inspired by Spring Data). Then use commonly used methods: find, findAll, save, count or write your owns.

class UserRepository(em: EntityManager) : DomainRepository<User, Long>(em) {

    override val domainClass: KClass<User>
        get() = User::class

}