3 ms·

I personally don’t really like builders. They work in some situations. But if I’m pulling the record from the DB and I only need to set some data on it that is

by vips7L 2y ago

I personally don’t really like builders. They work in some situations. But if I’m pulling the record from the DB and I only need to set some data on it that is overkill and more complex than need be. The object is already constructed in a valid state.

mrkeen 2y ago
> The object is already constructed in a valid state. But that's the entire value proposition of do-not-allow-construction-of-invalid-state! If a User is actually a User, then you can say "the object is already constructed in a valid state". If you decide to be 'less dogmatic' and instead construct Users-which-may-or-may-not-be-users-just-throw-an-ex-if-theyre-no-good, then you cannot say that the object is already constructed in a valid state.
- vips7L 2y ago
  I genuinely don't know what you're trying to say here. Perhaps you can show me in code.
cess11 2y ago
That's not the situation described above where data is partial. In your case I would copy rather than mutate, unless I'm actually getting noticably higher profits from lower memory usage during the time between getting the object and GC. This hasn't happened to me yet.
- vips7L 2y ago
  Maybe I'm not getting what you're saying but the data is partial? In the situation above we have a valid record created by someone else. This is pseudocode obviously, but I genuinely don't know what copying or building or immutability is going to buy me here other than being more complex. There is no worrying about the record being in an invalid state because it could have never gotten to the database in an invalid state. class User { Long? id; String email; String? name; Integer? age; Sex? sex; Avatar? avatar; User(String email) { this.email = email; } } record ProfileVm(String? name, Integer? age, Sex? sex, Avatar? avatar) {} // some ui controller var user = findById(id) if (user == null) { return notFound(); } var vm = ProfileVm.fromJson(request.json()); user.setName(vm.name()); user.setAge(vm.age()); user.setSex(vm.sex()); user.setAvatar(vm.avatar()); user.save(); return ok();

by vips7L 2y ago

mrkeen 2y ago

> The object is already constructed in a valid state. But that's the entire value proposition of do-not-allow-construction-of-invalid-state! If a User is actually a User, then you can say "the object is already constructed in a valid state". If you decide to be 'less dogmatic' and instead construct Users-which-may-or-may-not-be-users-just-throw-an-ex-if-theyre-no-good, then you cannot say that the object is already constructed in a valid state.

vips7L 2y ago
I genuinely don't know what you're trying to say here. Perhaps you can show me in code.

cess11 2y ago

That's not the situation described above where data is partial. In your case I would copy rather than mutate, unless I'm actually getting noticably higher profits from lower memory usage during the time between getting the object and GC. This hasn't happened to me yet.

vips7L 2y ago
Maybe I'm not getting what you're saying but the data is partial? In the situation above we have a valid record created by someone else. This is pseudocode obviously, but I genuinely don't know what copying or building or immutability is going to buy me here other than being more complex. There is no worrying about the record being in an invalid state because it could have never gotten to the database in an invalid state. class User { Long? id; String email; String? name; Integer? age; Sex? sex; Avatar? avatar; User(String email) { this.email = email; } } record ProfileVm(String? name, Integer? age, Sex? sex, Avatar? avatar) {} // some ui controller var user = findById(id) if (user == null) { return notFound(); } var vm = ProfileVm.fromJson(request.json()); user.setName(vm.name()); user.setAge(vm.age()); user.setSex(vm.sex()); user.setAvatar(vm.avatar()); user.save(); return ok();