Hexagonal Architecture

The term "hexagonal architecture" stems from Alistair Cockburn and has been around for quite some time (The primary source for the term "Hexagonal Architecture" is Alistair Cockburn's blog post at https://alistair.cockburn.us/hexagonal-architecture/). It applies the same principles that Robert C. Martin later described in more general terms in his clean architecture:

Figure 2.4: A hexagonal architecture is also called a "ports-and-adapters" architecture since the application core provides specific ports for each adapter to interact with

The preceding figure shows what a hexagonal architecture might look like. The application core is represented as a hexagon, giving this architecture style its name. The hexagon shape has no meaning, however, so we might just as well draw an octagon and call it "octagonal architecture." According to legend, the hexagon was simply used instead of the common rectangle to show...