Assignment No.6

Which of the following is correct about Behavioral design patterns.

• These design patterns are specifically concerned with communication between objects.

• These design patterns provide a way to create objects while hiding the creation logic, rather than instantiating objects directly using new operator.

• These design patterns concern class and object composition. Concept of inheritance is used to compose interfaces and define ways to compose objects to obtain new functionalities.

• None of the above.

Which of the following describes the Command pattern correctly?

• In this pattern a class represents functionality of another class.

• This pattern creates a chain of receiver objects for a request.

• This pattern provides a way to evaluate language grammar or expression

• In this pattern a request is wrapped under an object as command and passed to invoker object.

Which of the following describes the Strategy pattern correctly?

• In this pattern, a class behavior changes based on its state.

• In this pattern, a null object replaces check of NULL object instance.

• In this pattern, a class behavior or its algorithm can be changed at run time.

• In this pattern, an abstract class exposes defined way(s)/template(s) to execute its methods.

In the Publish-Subscribe messaging model, the subscribers register themselves in a topic and are notified when

new messages arrive to the topic. Which pattern does most describe this model?

• Adapter

• Notifier

• Observer

• State

A pattern that is intended to provide a means to define a family of algorithms and encapsulate each one as an

object for interchangeable use:

• Strategy Pattern

• Abstract Factory Pattern

• Visitor Pattern

• State Pattern

Which type of design patterns are specifically concerned with communication between objects?

• Creational Design Patterns

• Structural Design Patterns

• Behavioral Design Pattern

• J2EE Design Patterns

In below list which is not a Behavioral Design Pattern?

• Command

• Observer

• Proxy

• Strategy