Software Design Multiple Choice Questions on “The Facade and Mediator Patterns”.
1. Which of the following is true for facade pattern?
a) The Façade pattern is a broker pattern that eases interaction between a client and a sub-system of suppliers
by providing a simpler interface to the sub-system
b) Sub-systems may contain many classes with complex interfaces and relationships, but often clients only need basic services that can be supplied through a simple interface
c) The broker class, called a façade, provides basic, simplified services to clients by taking upon itself the job of dealing with a complex sub-system
d) All of the mentioned
Answer: d
Clarification: All of the mentioned is true for facade pattern.
2. Which of the following belongs to iterator pattern?
a) They delegate activities to other portions of the sub-system to which they provide an interface
b) The details of such delegations depend on the sub-system in question
c) The behavior follows the general outline of a broker pattern interaction
d) None of the mentioned
Answer: d
Clarification: All of the statements belongs to facade pattern.
3. Which of the following i correct?
a) The Mediator pattern provides a means of increasing coupling
b) In the Mediator pattern, interacts with one another, collaborating objects and with a special mediator class
c) The objects are coupled only to the mediator, which contains all the code for coordinating the collaboration
d) All of the mentioned
Answer: c
Clarification: Rest other are false-The Mediator pattern provides a means of reducing coupling, In the Mediator pattern, classes interacts only with a special mediator class.
4. Which of the pattern all the classes coupling is reduced?
a) Iterator
b) Facade
c) Mediator
d) Proxy
Answer: c
Clarification: Coupling is reduced as interaction is only to special mediator class.
5. Which of the following is for Facade Pattern?
a) Interaction is begun by one of the collaborators or a client object outside the collaboration
b) The object directs the collaboration, with all communication going between it and the colleagues in the interaction
c) All of the mentioned
d) None of the mentioned
Answer: d
Clarification: All of the mentioned are for mediator pattern.
6. Which of the following is a type of broker pattern?
a) Mediator
b) Facade
c) None of the mentioned
d) All of the mentioned
Answer: d
Clarification: All of the mentioned are types of broker pattern.
7. Which of the following does not follow the sequence of the mediator pattern?
a) As in any broker pattern, the Mediator receives a request for service at last
b) It then controls an interaction with the collaborating colleagues to supply the service
c) If one collaborator needs help from another, it notifies the Mediator object, which obtains the needed service from another collaborator
d) None of the mentioned
Answer: a
Clarification: As in any broker pattern, the Mediator receives a request for service at first.
8. The Mediator pattern has which of the following advantages?
a) It decouples collaborators, making them more changeable and reusable
b) It centralizes control of an interaction in the mediator class, making it easier to change, thus increasing modifiability
c) It simplifies the collaborators, making them easier to understand, and hence to change
d) All of the mentioned
Answer: d
Clarification: All the mentioned are advantages for mediator pattern.
9. Which are the drawback for mediator pattern?
a) It may also increase collaborator cohesion
b) Forcing collaborator interaction through the mediator may compromise performance
c) All of the mentioned
d) None of the mentioned
Answer: b
Clarification: Increase in collaborator cohesion is advantage.
10. Which of the following is consequence of mediator class?
a) They makes a sub-system easier for clients to use
b) Lowers the coupling between the client and the sub-system
c) Increase re-usability by adapting a sub-system’s interface to client needs
d) It encapsulates an interaction, making the interaction easier to change
Answer: d
Clarification: Rest others are consequence of facade class.