Chapter 16, Problem 16.1E

Explanation of Solution

‘provides’ interface:

It is the interface that defines the services that are provided by the component and also defines the methods that can be called by a user of the component.

‘requires’ interface:

It is the interface that defines the services that must be provided by other components in a system if a component operates correctly. If these are unavailable, then the component does not work.

Uses of ‘provides’ and ‘requires’:

• These interfaces are used in the component because the use of component is completely independent of its implementation.
• When the interfaces are not used in the component interactions, then the coupling between the components increases and it becomes difficult to interchange one component for an equivalent component with the same interface.
• A component should be independent so that it becomes easy to compose and deploy without specific components. But if the components are not independent then it requires ‘provides’ services externally and ‘requires’ interface explicitly.