Object-Oriented Approach 1: Enums and Interfaces

Learning Outcomes

1. Create an enum

2. Create an interface

3. Create an abstract class

Oracle Academy

• 2 Class Design and Exceptions

  • 2-1: Inheritance - Working with Pre-Written Code

Textbook

• 8 Classes and Objects: A Deeper Look

• 10 Object-Oriented Programming: Interfaces (10.9 and 10.10)

Tutorial / Practice Activity

• 2-1 Practice: JavaBank, Bike Project, Calculator

  • JavaBank, you can create a new project in IntelliJ and drag in the java files

  • Calculator

• Practice Quiz on Interfaces

Lesson Plan

• Mindfulness

• Previous week review

• Repl.it

• Resource reinforcement and clarification

• Object class vs driver class

• enum

  • Represents a fixed set of special objects (enum constants)

  • All instances of the class are created in the class

  • Simple usage - just objects

  • In IntelliJ:

    • Right click src, new -> class -> kind: enum

    • Enter switch (myEnumVar) and press Alt+Enter to Create missing 'switch' branches

  • Class Enum methods

    • enum constant value accessible with name method

  • Class diagram, inherits from Enum

  • More complicated example - constructor, methods

  • From Planet example MERCURY (3.303e+23, 2.4397e6) is like Planet MERCURY = new Planet(3.303e+23, 2.4397e6);

• Interface

  • Like a contract.

  • Variables declared in an interface are implicitly public static final.

  • Use when classes that implement aren't related.

  • Functional interface

• Abstract Class

  • A class that can't be used to make objects.

  • Use when classes that extend will be somewhat related.