Simple stuff. If later the calculation will be performed in-house, just implement a new class inside that BC and reconfigure the DI Container. However, the specifics of the communication with durable storage mechanisms are handled in the infrastructure layer. It was a Thursday. In DDD,Methods that don’t really fit on a single entity or require access to the repository are contained within domain services, The domain service layer can also contain domain logic of its own and is as much part of the domain model as entities and value objects. Domain-Driven Design (DDD) concept was introduced by first Eric Evans in 2003. Domain services are different from infrastructural services because they embed and operate upon domain concepts and are part of the ubiquitous language. If they're not, they're a DS, even if it seems related to that aggregate somehow. Jest to sposób myślenia, ustalania uwagi i priorytetów mających na celu przyśpieszenie (lub w ogóle umożliwie-nie powstania) projektów zmagających się ze złożoną domeną. DDD jako nazwa zyskało popularność w 2003 roku po publikacji książki Erica Evansa „Domain-driven De- As a result, there is a cloud of confusion surrounding the notion of services as one tries to distinguish between application services, domain services, infrastructural services, SOA services, etc. An application service has an important and distinguishing role - it provides a hosting environment for the execution of domain logic. Infrastructural services are instead focused encapsulating the “plumbing” requirements of an application; usually IO concerns such as file system access, database access, email, etc. Also DS shouldn't care about state, they represent domain behaviour only (their implementation should be stateless). Domain-Driven Design is a concept introduced by a programmer Eric Evans in 2004 in his book Domain-Driven Design: Tackling Complexity in Heart of Software.. The operation relates to a domain conceptthat is not anatural part of an Entity or Value Object. This is the type of logic that we put in a Domain Service instead 2. This attributes an encapsulating role to the service - the service is an instance of the facade pattern. For example, you want to check an account balance before debiting an account. On the other end of the spectrum is over-utilization of domain services leading to an anemic domain model in what essentially becomes a separation of data, stored in entities, and behaviors, provided by the service. There are a number of steps required for a computer to fulfill that command and we would never expect a human to issue a more specific command such as “load an account entity with id A from account repository, load an account entity with id B from account repository, call the debit method on the account A entity…”. Or you want to perform a simple calculation according to domain rules. It doesn't mean you have to implement it in one way or another. In a business case we can use multiple DS and this might look like the Anaemic Domain. Again, the content is very much based on the books Domain-Driven Design: Tackling Complexity in the Heart of Software by Eric Evans and Implementing Domain-Driven Design by Vaughn Vernon and I highly recommend you to read both of them. The objective o… A common problem in applying DDD is when an entity requires access to data in a repository or other gateway in order to carry out a business operation. 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