Re: Avoid injecting Service/Repository in an Entity

First, the domain does not access repositories. As for your case you
already have a collection of students, implement a method in the collection
class that shows the students repeated. And I apologize for my English, I
have helped..


2014-03-26 12:05 GMT-03:00 Stefan A. <[email protected]>:

>
>
> Maybe an EnrollmentSpecification? Students must satisfy this specification
> in order to be added to a class.This specification would use a repository
> to find the answer. As stated in earlier comments, you don't want to pull
> every student from the database, but remember that repositories can also
> have methods that compute counts, or give yes or no answers, in this case
> maybe isStudentEligibleForEnrollment method in your repository would help.
>
>
> On Tue, Mar 25, 2014 at 8:15 PM, Brian Sayatovic <[email protected]>wrote:
>
>>
>>
>> Sounds like Enrollment itself could  be an entity. Would that make things
>> easier?
>> On Mar 25, 2014 1:03 PM, <[email protected]> wrote:
>>
>>>
>>>
>>> Hi Everyone,
>>>
>>> From what I've read, this is really bad. But I have the following use
>>> case so wondering how to do this in the proper DDD way. The business rule
>>> is contrived but it is very similar to what i have in real life. I just
>>> cannot disclose the use case due to NDAs.
>>>
>>> I have a class named Class. A class can have students in it. There is a
>>> business rule such that if a student with the same surname belongs to any
>>> current of any other class, they cannot be added to the class.
>>>
>>> So on Class, i have a method named AddStudent. Just wondering how would
>>> the algorithm be implemented in a proper DDD sense
>>>
>>> public class Class
>>> {
>>>
>>> public void AddStudent(Student student)
>>> {
>>>
>>> // Call a repository to get all the students enrolled in all classes
>>> // If any students surname matches the surname of the student passed in,
>>> do not thing
>>> // otherwise add the student
>>>
>>> }
>>>
>>> }
>>>
>>>
>>>
>>>
>>>
>  
>



-- 
*Veranildo Veras*
*Analista / Desenvolvedor de Sistemas*