Use Case Diagram概念解析

这是一个自动售货机的部分UseCase图:


 

注意：
一、解释途中Restock 和 Collect的含义：
1. Restocking a soda machine
2. Collecting the money from a soda machine.

二、Inclusion和Extension

1. Inclusion
the “Restock” use case would be <<include>> (expose the inside).

2. Extension

扩展：The new use case is said to extend the original one because it adds new steps to the sequence in the original use case , also called the base use case.

扩展点：Extension can only take place at specific designated points within the base use case’s sequence . These points are called, appropriately, extension points . In the “Restock” use case, the new steps (noting the sales and designating the appropriate refills) would occur before the supplier’s representative opened the machine and was ready to fill the compartments of the soda brands. For this example, the extension point is “before filling the compartments.”