英文:
How to read this UML diagram?
问题
我在航空业工作，我试图理解这个UML图。我在大学学过一点UML。你可以帮助我解释这个图吗？
- << extend >> 和 << select >> 有什么区别？
- 大黑箭头代表什么？
我不明白如何阅读这张图。
英文:
I work in the aviation industry, and I am trying to understand this UML diagram. I did a little bit of UML in college. Can you help me to interpret this diagram?
- What is the difference between << extend >> and << select >>?
- What do the big black arrows mean?
I didn't understand how to read the graph.
答案1
得分: 1
«extend» 和 «select» 是在该模型领域中赋予了特定含义的陈规定型。通常，会使用配置文件来定义这些定型和它们的含义。所以最好的做法是联系图表的作者并询问相关信息。没有通用的答案。看起来这些可能是要表示需求。
带有菱形的“黑色箭头”是赋予了组合聚合属性的关联。菱形一侧负责另一侧的生命周期。这意味着当它自身被销毁时，它会销毁它们。
关于“class”（根据UML 2.5 第99页上的Axel Scheithauer的评论）的有趣说明：
如果对分类器使用默认符号，应该在名称上方显示与分类器的元类相对应的关键字。每个元类的关键字在附录C中列出，并在每个分类器子类的符号中指定。不需要关键字来指示元类是Class。
因此，在那里放置该关键字就像在汽车上涂上“car”以使其成为汽车一样，显然是多余的。
英文:
«extend»and «select» are stereotypes which were given a certain meaning in the domain of that model. Usually a profile is used to define the sterotypes and their meaning. So the best is you contact the author of the diagram and ask about it. There is no general answer. It looks a bit like these are meant to be requirements.
The "black arrows" with the lozenge are associations that are given a composite aggregation attribute. The lozenge-side is responsible for the lifetime of the other side. Means it will destroy them when it is destroyed itself.
Fun note about the «class» (as per comment from Axel Scheithauer from p. 99 of UML 2.5:
> If the default notation is used for a Classifier, a keyword corresponding to the metaclass of the Classifier shall be shown in guillemets above the name. The keywords for each metaclass are listed in Annex C and are specified in the notation for each subclass of Classifier. No keyword is needed to indicate that the metaclass is Class.
So putting that keyword there is like painting "car" on a car to make it a car, obviously.
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