Object Oriented Design

Multiple Choice Questions

1. What does Modularity refer to in Object-Oriented Analysis and Design?
   • 1. The ability to change the functionality of an application without impacting the user interface.
   • 2. The degree to which a system is composed of discrete components.
   • 3. The process of creating objects from classes.
   • 4. The ability of different classes to be treated as instances of the same class.
2. In the context of software design, what does Low Coupling imply?
   • 1. High dependency between different modules of a system.
   • 2. Minimal impact on other components when a component is changed.
   • 3. The ability of a system to handle unexpected inputs gracefully.
   • 4. The degree to which a system can be used in more than one application.
3. Which principle is best demonstrated by creating a class that does not represent a real-world entity but aids in design?
   • 1. Information Expert
   • 2. Polymorphism
   • 3. Pure Fabrication
   • 4. High Cohesion
4. In Object-Oriented Design, what is a ‘Use Case’ primarily used for?
   • 1. Defining the structure of different classes in a system.
   • 2. Describing how users interact with the system to achieve specific goals.
   • 3. Illustrating the relationships and dependencies among different classes.
   • 4. Outlining the sequence of messages between objects in a particular interaction.

Short Answer Questions

1. Explain the concept of ‘Aggregation’ in object-oriented design with an example.

2. Describe the difference between ‘Functional Requirements’ and ‘Non-Functional Requirements’ in software development.

3. Illustrate the concept of ‘Polymorphism’ with a code example in Java.

4. Discuss the role and importance of ‘Use Cases’ in understanding user interactions with a system.

5. Give an example of applying the ‘Law of Demeter’ in a Java class.

Code-Based Questions

1. Refactor the given code snippet to improve its adherence to the KISS principle.

public class StudentGradeCalculator {

    public double calculateFinalGrade(int[] assignmentScores, 
                                      int midtermScore, 
                                      int finalExamScore) {
        double assignmentAverage = 0;
        

        for (int i = 0; i < assignmentScores.length; i++) {
            assignmentAverage += assignmentScores[i];
        }
        assignmentAverage /= assignmentScores.length;
        
        double decimalMidterm = midtermScore / 100.0;
        double decimalFinalExam = finalExamScore / 100.0;
        double decimalAssignments = assignmentAverage / 100.0;
        
        double weightedMidterm = decimalMidterm * 30;
        double weightedFinalExam = decimalFinalExam * 30;
        double weightedAssignments = decimalAssignments * 40;
        
        double finalGrade = weightedMidterm + weightedFinalExam + weightedAssignments;
        
        finalGrade *= 100;
        
        return finalGrade;
    }
}

2. Given a high coupling scenario in the following Java application, suggest improvements to reduce coupling and rewrite the code.

// EmailNotification.java
public class EmailNotification {
    public void sendEmail(String message, String recipient) {
        // Logic to send an email
        System.out.println("Sending email to " + recipient + ": " + message);
    }
}

// OrderManager.java
public class OrderManager {
    private EmailNotification emailNotification;

    public OrderManager() {
        this.emailNotification = new EmailNotification(); 
    }

    public void processOrder(String orderDetails, String customerEmail) {
        // Logic to process the order
        System.out.println("Order processed: " + orderDetails);

        emailNotification.sendEmail("Your order has been processed.", customerEmail);
    }
}

// Main.java
public class Main {
    public static void main(String[] args) {
        OrderManager orderManager = new OrderManager();
        orderManager.processOrder("Book: Java Programming", "[email protected]");
    }
}

Conceptual Questions

1. Given a Shape interface with a method draw(), and classes Circle and Square implementing Shape, explain how adding a new Triangle class without modifying existing code aligns with the Open/Closed Principle (OCP).