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What do these arrows in design pattern diagrams mean?
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Problem
I am learning about software design patterns by reading Wikipedia pages about them. A lot of the patterns such as the bridge pattern have diagrams with boxes and different kinds of arrows:
Source: Wikipedia
Do these diagrams stem from a standard? Why do some arrows have different ending markings? Also, why are some of them dotted?
Source: Wikipedia
Do these diagrams stem from a standard? Why do some arrows have different ending markings? Also, why are some of them dotted?
Solution
The arrows mean distinct things. This is a UML (unified modeling language) diagram. Rules for reading and writing these diagrams are pretty well-established, and you should be able to look up some references.
In that diagram, the hollow arrow means generalization (i.e., inheritance, IS_A), and the hollow diamond means aggregation (i.e., a kind of association, HAS_A). The dotted line connects a comment/label and contains auxiliary/meta information (I believe, but double check this one).
In that diagram, the hollow arrow means generalization (i.e., inheritance, IS_A), and the hollow diamond means aggregation (i.e., a kind of association, HAS_A). The dotted line connects a comment/label and contains auxiliary/meta information (I believe, but double check this one).
Context
StackExchange Computer Science Q#6973, answer score: 4
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