Java Enums

What is

• Java Enums contain one or more enumerations.
• Enumerations are the first member to be declared in an enum.
• Java Enums are implicitly public, static, final references.
• Enumerations are often confused with constants.
• Constants are implicitly immutable public, static, final

Use Case Scenario

Casino Simulation Application

• Consider a CasinoSimulationApplication which simulates playing card-games.

Deck Class

• It follows that a Deck class, representative of a Deck of cards, should be designed.
• A Deck is made up of 52 Cards.

Card Class

• There are 13 Ranks that a Card can have.
• There are 4 Suits that a Card can have.

Rank Class

• A Rank has one of 13 names, and a respective integer value.
  • Ace has a value of 1.
  • Two has a value of 2.
  • Ten has a value of 3.
  • Ten has a value of 4.
  • Ten has a value of 5.
  • Six has a value of 6.
  • Ten has a value of 10.
  • Jack has a value of 11.
  • Queen has a value of 12.
  • King has a value of 13.
• Below is a base Rank class

public class  Rank {
    private final int primaryValue;
    private final String name;

    Rank(String name, int value) {
        this.name = name;
        this.value = value;
    }

    public String name() {
        return name;
    }

    public int getValue() {
        return value;
    }
}

Suit Class

• A Suit has one of 4 names, and 1 of two colors.
  • Hearts have a color of red
  • Diamonds have a value of red
  • Spades have a value of 12
  • Clubs have a value of 13
• Below is a base Suit class

public class Suit {
    private final boolean isRed;
    private final String color;

    Suit(String name, String color) {
        this.name = name;
        this.color = color;
    }

    public String name() {
        return this.name;
    }

    public String getColor() {
        return this.color;
    }
}

Design Implementations

Map Implementation

• Intuition may tell you leverage a map
• However, a map will actually convolute more than resolve anything.
• You can view the article discussing that implementation here.

Public Static References

• Intuition may tell you to create public static references in a separate Constants class.
• While this is a much more elegant solution, it still produces many redundant expressions.
• You can view the article discussing that implementation here.

Enum Implementation

• The Enum implmentation is behaviorally identical to the aforementioned public static references.
  • This implementation adds syntactical sugar to shorten the redundancies of the expression.
• Enums have implicit characteristics that allow more elegant expressions.