uml - 什么是 UML 图中的可导航性？

Question

什么是 UML 图中可导航性的示例？我的教授提供了下图，但我似乎无法弄清楚:

Answer 1

这显示了导航性。 A 可以看到(意味着它有一个属性引用) B 。相反， B 不知道/引用 A 。
UML 2.5 规范页。 18:

• Arrow notation is used to denote association end navigability. By definition, all class-owned association ends are navigable. By convention, all association-owned ends in the metamodel are not navigable.

• An association with neither end marked by navigability arrows means that the association is navigable in both directions.

甚至更相关的 p。 200:

Navigability notation was often used in the past according to an informal convention, whereby non-navigable ends were assumed to be owned by the Association whereas navigable ends were assumed to be owned by the Classifier at the opposite end. This convention is now deprecated. Aggregation type, navigability, and end ownership are separate concepts, each with their own explicit notation. Association ends owned by classes are always navigable, while those owned by associations may be navigable or not.

所以你应该改用点表示法: