Design Patterns Simplified - Part Twelve (Composite)

In the above interface, we have declared ShowYearsOfExperience as it's common to all the employees be itthe CEO, manager, or junior.

Now we will create the Manager class which will be the composite class.
The above composite class hasa set of methods to handle operations related to subordinates apart from implementing common method (ShowYearsOfExperiance) defined in IEmployee.

Now the time has come to create Leaf object class which will cater to junior employees.
So at this point, we are done with creating key components (Component/Composite/Leaf), now let’s see how client uses them.
Output:


You can see in the above output how employee’s structure is getting shown in the hierarchical fashion using composite pattern.

A point to be noted here that Composite pattern assumes that both composite (i.e. Manager) and individual (JuniorEmployee) objects are used and accessed in similar way, this is the reason we extracted common behavior (YearsOfExperiance) and put in the Component (IComponent).

To summarize, composite pattern can be used in cases where hierarchical representation of objects are required and both individual and composite objects are treated in the same way.