Software Fortresses: Modeling Enterprise Architectures

14.5. The CheckInventory Drawbridges

Now I'll turn my attention to the drawbridges used by the CheckInventory treaty, starting with the VendorGateway fortress. Figure 14.12 shows the SAD for CheckInventory.

Figure 14.12. New SAD for CheckInventory

Superficially the CheckInventory treaty looks like the ProcessOrder treaty, as you can see by comparing Figure 14.12 to Figure 14.9. Both treaties involve three fortresses. Both feature an asynchronous relationship with the Inventory fortress. However, this is where the similarities end.

The first difference is at the gateway level. The incoming request to the CustomerGateway fortress originated with ...