Instantiating Entities in Interactor

[Reed Law]

My Interactors typically have 2 or 3 steps:

1. Load up data from a Repository needed by this particular use case
2. Instantiate entities that interact with the data and produce a set of results (optional)
   
3. Save new data to the Repository

Step 2 is optional because sometimes a use case is a plain CRUD action that only needs to update the database. Other times I need the full blown object-oriented dance of the entities in order to get the result that is either presented directly in a view or saved to the database.

My question is, how should I clean up step 2? Some of the methods that instantiate entities are very long and I feel they need their own separate class. What would that class be called? I'm using Serializers for presenting data from Repositories to the views. I need something like a reverse serializer or de-marshaller.

[Caio Fernando Bertoldi Paes de Andrade]

You can use the Builder Pattern, and have a method in the Builder that builds an entity from a data structure. :)

Hope this helps,

Caio

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[Jop van Raaij]

I'd use a RepositoryGateway to translate data from the repository to entities and vice versa. Step 1 and 2 are therefore not in the interactor, but in the RepositoryGateway. The interactor can now concentrate on business logic only. Within the interactor, you only call repository.loadUser(id), returning a User entity and repository.saveUser(User). If the RepositoryGateway becomes too large, you could think about splitting the gateway by entity or some other logical rule.

On Thursday, December 19, 2013 4:36:24 PM UTC+1, Caio Fernando Bertoldi Paes de Andrade wrote:

You can use the Builder Pattern, and have a method in the Builder that builds an entity from a data structure. :)

Hope this helps,

Caio

On 19 Dec 2013, at 12:55, Reed Law <ree...@gmail.com> wrote:

My Interactors typically have 2 or 3 steps:

1. Load up data from a Repository needed by this particular use case
2. Instantiate entities that interact with the data and produce a set of results (optional)
   
3. Save new data to the Repository

Step 2 is optional because sometimes a use case is a plain CRUD action that only needs to update the database. Other times I need the full blown object-oriented dance of the entities in order to get the result that is either presented directly in a view or saved to the database.

My question is, how should I clean up step 2? Some of the methods that instantiate entities are very long and I feel they need their own separate class. What would that class be called? I'm using Serializers for presenting data from Repositories to the views. I need something like a reverse serializer or de-marshaller.

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[Andreas Schaefer]

I agree with Jop. entity instanciation and persistance should not be done by interactors but by the gateway implementations.