Reactive Design Patterns

Chapter 10. Message flow

Now that you have established a hierarchy of encapsulated modules that represent an application, you need to orchestrate them and realize the solution. The key point developed throughout the previous chapters is that modules communicate only asynchronously by passing messages. They do not directly share mutable state. You have seen many advantages of this approach along the way, enabling scalability and resilience, especially in concert with location transparency. The alternative, shared-state concurrency, is hard to get right.

There is one further advantage: basing a distributed design exclusively on messages allows you to model and visualize the business processes within your application as message flows. This helps ...