
Software Complexity and Modeling ◾ 23
support multiple views and multiple controllers and therein lies the power
of the model.
How does the MVC work? A controller sends commands to a view
when it is necessary to change the presentation of the model, e.g., when a
bar graph is converted to a line graph. A controller also noties the model
to update state. Upon a state change, such as data modication, the model
may notify the controller to update its views. A view requests data from
the model to construct its presentation.
e MVC supports the clear decomposition of functionality. Com-
ponents either request services or provide services. Ex