Doma2 Criteria API with Immutable entity.

0_.md

associateの例 を Immutable Entity でどうするか

1:1:N ぐらいなら collect で何とでもなる

    Employee_ e = new Employee_();
    Task_ t = new Task_();
    Address_ a = new Address_();

    Map<Employee, Tuple2<List<Task>, Optional<Address>>> result = nativeql
        .from(e)
        .innerJoin(t, on -> on.eq(e.id, t.asiginee))
        .innerJoin(a, on -> on.eq(e.addressId, a.addressId))
        .orderBy(c -> c.asc(e.employeeName))
        .select(e, t, a)
        .collect(
           groupingBy(
               Tuple3::getItem1, 
               teeing(
                 mapping(Tuple3::getItem2, toList()),
                 mapping(Tuple3::getItem3, first()),
                 Tuple2::new
               )
           )
        );

inner join なのに Address がOptionalになってしまうのと、Tuple3::getItem1 とかが何を表してるか分かりづらい……。 joined entity type から entity type を取り出すのに Metamodel のメソッドが使えると解決するかも？