Questions

• Reading?
• Quiz?
• Homework?

Concept - What makes a good class?

• Mathematical concepts
• Things from real-life
• Things from the domain of the problem
• Actors
  • Scanner
  • Random
• Utliity classes
  • Math
  • Arrays
  • Collections
• Class with only a main method

Activity - Picking classes

Record your participation in Piazza clicker question Lesson13 Q1

We are simulating a public library with books that can be checked out and returned. Each book has an author and an indication of whether it is on the shelf. A patron can check out and return books. Which of these would be good classes. Check all that are appropriate

1. Read
2. Book
3. Author
4. Checkout
5. Library
6. IsOnShelf
7. Patron

Activity - Cohesive public interface

Record your participation in Piazza clicker question Lesson13 Q2

You are designing a class CreditCard as part of a credit card services program. Which of these methods would you include in the public interface to make the class cohesive? Check all that apply.

1. makePayment
2. getCustomerAddress
3. charge
4. getSafetyDepositBoxNumber
5. calculateMonthlyFees
6. getAllThisCustomerAccounts

Activity - Problematic method

Record your participation in Piazza clicker question Lesson13 Q3

What is wrong with this method of the Book class? May be more than one answer

public void isOnShelf
{
   if (onShelf)
   {
      System.out.println("The book is on the shelf");
   }
   else
   {
      System.out.println("The book is NOT on the shelf");
   }

}

1. introduces a dependency
2. has a side effect
3. is not cohesive
4. combines a mutator and an accessor

Concept - Design Patterns

• Keeping a total
• Counting events
• Managing properties of an object
• Modeling distinct states
• Describe an object's position

Activity -

Record your participation in Piazza clicker question Lesson13 Q4

You are writing a Student class with instance variables studentID, name, gpa which is calculated in a updatGpa method.

Which instance variables should have both a getter and a setter? Check all that apply

1. studentID
2. name
3. gpa

Concept - Relationships between classes

• Dependency
  • knows about or uses
  • 
• Aggregation
  • has-a
  • 
• Inheritance
  • is-a
  • 

Activity - Relationships between classes

Record your participation in Piazza clicker question Lesson13 Q5

Think of a pair of classes that demomstrate one of the types of relationships