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I agree with the author roughly about the benefits and disadvantages. And would probably add to the disadvantages that synchronous sequences are harder to model

I agree with the author roughly about the benefits and disadvantages. And would probably add to the disadvantages that synchronous sequences are harder to model, since with pure asynchronous messaging all components will get state machines. Regarding the advantages: Interfaces and dependency injection (with or without frameworks) also solve the first two bullet points also rather nicely. And they keep the synchronous nature and strictly typed interfaces. The third point can be achieved with data binding or interfaces which allow for subscriptions (e.g. via classical "Event"s or Observables).

elcritch 9y ago
In your first statement did you intend to mean that asynchronous was an advantage or disadvantage? I’d take objects being modeled as independent state machines as a significant benefit. It doesn’t seem that dependency injection really provides the benefits of the second advantage as the author describes it. Specifically he mentions that the recipient can decide wether and/or how to respond to a message. DI doesn’t provide that. The point isn’t _just_ that you can dynamically swap objects, which seems precarious in a lot of ways as values/results in referenced objects could change under your feet which without pervasive usage of observers means lots of easy to make mistakes for devs. That means for a DI system to really be dynamic in the same sense that you need an event system / observer pattern in addition to DI to provide similar benefits while being more complicated due to now three layers of abstraction (at least) required. Whereas an “MOP" system encourages devs to think about outside changes from the start and makes it the path of least resistance while reusing the same abstraction to enable dynamic target and 1-to-many fanning. The usage of DI systems results in much more ceremony and generally results in overly complicated system architecture as compared to a good messaging system as the author highlights. Now a really complex message topology can become really confusing which results in similar architectural issues as an DI / event based system if not checked.

elcritch 9y ago

In your first statement did you intend to mean that asynchronous was an advantage or disadvantage? I’d take objects being modeled as independent state machines as a significant benefit. It doesn’t seem that dependency injection really provides the benefits of the second advantage as the author describes it. Specifically he mentions that the recipient can decide wether and/or how to respond to a message. DI doesn’t provide that. The point isn’t _just_ that you can dynamically swap objects, which seems precarious in a lot of ways as values/results in referenced objects could change under your feet which without pervasive usage of observers means lots of easy to make mistakes for devs. That means for a DI system to really be dynamic in the same sense that you need an event system / observer pattern in addition to DI to provide similar benefits while being more complicated due to now three layers of abstraction (at least) required. Whereas an “MOP" system encourages devs to think about outside changes from the start and makes it the path of least resistance while reusing the same abstraction to enable dynamic target and 1-to-many fanning. The usage of DI systems results in much more ceremony and generally results in overly complicated system architecture as compared to a good messaging system as the author highlights. Now a really complex message topology can become really confusing which results in similar architectural issues as an DI / event based system if not checked.