What is Aggregation ?

Aggregation

If two classes share association relationship, and one class can be said to be part of the other, the relationship is called aggregation. Aggregation expresses a relationship between a ‘whole’ and its ‘part’.

Example

When the implementation code is written, we have to decide on the actual container class like List, Vector,Array etc.

 

Aggregation = Association with "whole-part" relationship




Shown by hollow diamond at the "whole" side.

No lifetime control implied.