JDBI with kotlin using generics

jdbi_kotlin_generics.kt

    interface DAO {
    abstract fun list(): List<DbCitation>
    abstract fun listlimited(@Bind("limit") limit: Int): List<DbCitation>
    abstract fun count(): Int
}


abstract class Db<T: DAO>(var host: String,
              var user: String,
              var password: String,
              var db: String) {

    private var dao: T? = null
    private var jdbi: Jdbi? = null
    protected abstract var parser: JSONParser

    fun connect() {
        this.jdbi =
                Jdbi.create("jdbc:postgresql://$host/$db",
                        user,
                        password)
                        .installPlugin(PostgresPlugin())
                        .installPlugin(SqlObjectPlugin())
                        .installPlugin(KotlinPlugin())
                        .installPlugin(KotlinSqlObjectPlugin())
    }

    fun dao(): T? {
        if (dao == null)
            this.dao = this.jdbi?.onDemand<T>(T::class.java)

        return this.dao
    }

    fun listlimited(limit: Int): List<GenericCitation?>? {
        return this.dao()?.listlimited(limit)?.map { it -> this.parser.parse(it.data)}
    }