The separation of concerns that’s quoted as being an advantage of MVC is actually also an advance of a 3-layer/3-tier system. There too, the business logic is independent and can be used from different presentation tiers. A main difference is that in classic MVC the model can have a reference back to the view. This … Read more
My rule of thumb is generally to catch exceptions at the top level and log (or otherwise report) them there, because this is where you have the most information about the the error – most importantly the full stack trace. There may be some reasons to catch exceptions in other tiers, however: The exception is … Read more
You are correct that you don’t want Infrastructure to depend on UI(Web), but I break that rule sometimes. I would think instead of IViewModelMapping, create IMapper with method Map(). Then, the interface can have implementations that might have to do with view model mapping, or maybe just regular mapping. Either way, that interface can be … Read more
Wikipedia explains it better then I could From the article – Top is 1st Tier:
Yes, they should be of scope singleton. Services should be stateless, and hence they don’t need more than one instance. Thus defining them in scope singleton would save the time to instantiate and wire them. singleton is the default scope in spring, so just leave your bean definitions as they are, without explicitly specifying the … Read more
Short answer: No. Long answer: repository is responsible for turning persisted data back to entities (models) and vice versa. Model is a business Model representing a business entity. DTO on the other hand – while looks like Model – is concerned with transfer of the object between various environment and in essence is a transient … Read more
I try to seriously limit my business logic in the DB to only procs that have to do alot of querying and updating to perform a single application operation. Some may argue that even that should be in the app, but I like to keep the IO down if I can. Databases are great for … Read more
N-tier architecture usually has each layer separated by the network. I.E. the presentation layer is on some web servers, then that talks to backend app servers over the network for business logic, then that talks to a database server, again over the network, and maybe the app server also calls out to some remote services … Read more
Wikipedia: In software engineering, multi-tier architecture (often referred to as n-tier architecture) is a client-server architecture in which, the presentation, the application processing and the data management are logically separate processes. For example, an application that uses middleware to service data requests between a user and a database employs multi-tier architecture. The most widespread use … Read more