UML knowledge
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UML relationships can be described using associations. An association describes a relationship between two or more classes. There are weak associations called dependencies that occur when a class references another class as a parameter or return type. Strong associations exist when a class holds a reference to another class. Aggregation represents a part-whole relationship where the whole class contains part classes. Composition is a strong life cycle association where if one class is deleted, associated classes are also deleted.
UML knowledge
- 1. 1 UML Knowledge Li-Wei Cheng
- 2. UML related knowledge - 1 2 Association The most abstract way to describe relationship between classes A kind of link between two classes or more Any relationship between object of two classes
- 3. UML related knowledge - 2 3 Weak Association (Dependency) If class A’s methods include parameter of Class B’s reference, or returns reference of Class B, it calls A depends on B. Strong Association If class A holds class B’s reference, it calls A have strong association with B.
- 4. UML related knowledge - 3 4 Aggregation (Association with part/whole relation) A part of relationship between Class A (whole) and Class B (part) Also called shared association Doesn’t state in any way that Class A owns Class B nor that there’s a parent-child relationship between the two
- 5. UML related knowledge - 4 5 Composition (Association with strong life cycle relation) A strong life cycle dependency between the two, meaning that when Class A is deleted then Class B is also deleted as result. Also called not shared association. Use more specific composition link instead of the aggregation link or association link.