uml

UML

Diagram types and short description of each:

Type	Relation	Implementation
Association	knows a	Contains a pointer or reference to another object.
		Undirected usually means: It has not been decided whether the association is directed or the association is bidirectional (can call each other).
Dependency	uses (temporarily) a	The independent class is a parameter variable or a local variable of a method of the dependent class.
Aggregation	has a	A class is a collection or container of other classes. The contained classes do not have a strong life cycle dependency on the container(-class) -> if the container is destroyed, its contents are not.
	is entirely made of	Association differs from aggregation only in that it does not imply any containment.
Composition	has a	= stronger form of aggregation. If the container is destroyed, its contents are also destroyed.
Inheritance	is a	A class is derived from another class.
Class template	is a	Template classes mean generic classes.

void return type can be omitted
Arrows are sometimes optional like in aggregation, composition, ...
- The worded relation refers to the direction the arrow would go (A --> B; A knows a B)
Relationship grouping
- Association
  - Dependency
  - Aggregation
  - Composition
- Generalisation
  - Inheritance
  - Template class
  - Interface

multiplicity
- *: 0, 1, or more
- 1: exactly this number
- 4..8: range (inclusive)
- 5..*: range (5 or more)

Object (here: BrokenPencil) of a certain class (here: Junk):

See BrokenPencil as an instance of Junk.

Possibilities via: