问题
Do generalization arrows in class diagram has to be strictly open or is there a margin of tolerance on style of this arrows?
回答1:
Open arrows are used together with a dashed/dotted line to represent dependencies.
I can't think of a standard way to use them with a regular line.
Furthermore, as Martin Fowler clearly indicates in UML Distilled, UML is just a notation. If the people that will read your diagrams are aware that open arrow = closed arrow, then feel free to use it. There is no strictness in UML.
回答2:
Each element in UML has to strictly follow the normative notation proposed in the standard. With so many symbols there is a high risk that a notation variant for a symbol coincides with the normative representation of another one
回答3:
Talking about UML designs without an image is like talking about girl without ...... :-) Here is the picture of UML2 connectors in the class diagram:
alt text http://www.forum-omondo.com/documentation_eclipseuml_2008/connectors_uml2.png
来源：https://stackoverflow.com/questions/2585508/generalization-arrows