Вивчайте Enums vs. Other Data Types | Getting Started with Enums

When deciding how to represent a fixed set of related values in Java, you may consider using enums, classes, interfaces, or primitive types. Each option has its place, but enums offer unique advantages in certain scenarios. Enums are designed for situations where you need a distinct set of named values, such as the suits of playing cards, the days of the week, or status codes. Unlike primitive types like int or char, enums provide type safety and make your code more readable and maintainable. While classes and interfaces are powerful for modeling behaviors and complex data, they are often unnecessary if all you need is to represent a closed set of possible values. Enums shine when you want to ensure that only valid, predefined values are used, reducing the risk of bugs and making your intentions clear to anyone reading your code.

Main.java


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package com.example;

public class Main {
    // Using integer constants
    public static final int HEARTS = 0;
    public static final int DIAMONDS = 1;
    public static final int CLUBS = 2;
    public static final int SPADES = 3;

    // Using enum
    public enum Suit {
        HEARTS, DIAMONDS, CLUBS, SPADES
    }

    public static void main(String[] args) {
        // Using integer constants
        int mySuitInt = HEARTS;

        // Using enum
        Suit mySuitEnum = Suit.HEARTS;

        System.out.println("Integer constant suit: " + mySuitInt);
        System.out.println("Enum suit: " + mySuitEnum);
    }
}

Choosing between integer constants and enums has significant implications for your code. Using integer constants can lead to mistakes, such as assigning an invalid value that does not represent any real card suit. With enums, the compiler enforces valid assignments, preventing many common errors. Integer constants also lack descriptive names when printed or logged, while enums provide clear, meaningful output. This makes enums a better choice for representing fixed sets of values, especially when you want to avoid invalid values and improve code clarity.

Main.java


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package com.example;

public class Main {
    public enum Suit {
        HEARTS, DIAMONDS, CLUBS, SPADES
    }

    public static void main(String[] args) {
        // Using an int: possible to assign an invalid value
        int mySuitInt = 42; // No compile-time error, but invalid

        // Using an enum: only valid values allowed
        Suit mySuitEnum = Suit.HEARTS; // Valid
        // Suit mySuitEnumInvalid = 42; // Compile-time error!

        System.out.println("Unsafe int value: " + mySuitInt);
        System.out.println("Safe enum value: " + mySuitEnum);
    }
}

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Main.java


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package com.example;

public class Main {
    // Using integer constants
    public static final int HEARTS = 0;
    public static final int DIAMONDS = 1;
    public static final int CLUBS = 2;
    public static final int SPADES = 3;

    // Using enum
    public enum Suit {
        HEARTS, DIAMONDS, CLUBS, SPADES
    }

    public static void main(String[] args) {
        // Using integer constants
        int mySuitInt = HEARTS;

        // Using enum
        Suit mySuitEnum = Suit.HEARTS;

        System.out.println("Integer constant suit: " + mySuitInt);
        System.out.println("Enum suit: " + mySuitEnum);
    }
}

Main.java


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package com.example;

public class Main {
    public enum Suit {
        HEARTS, DIAMONDS, CLUBS, SPADES
    }

    public static void main(String[] args) {
        // Using an int: possible to assign an invalid value
        int mySuitInt = 42; // No compile-time error, but invalid

        // Using an enum: only valid values allowed
        Suit mySuitEnum = Suit.HEARTS; // Valid
        // Suit mySuitEnumInvalid = 42; // Compile-time error!

        System.out.println("Unsafe int value: " + mySuitInt);
        System.out.println("Safe enum value: " + mySuitEnum);
    }
}

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Дякуємо за ваш відгук!

Секція 1. Розділ 3

Enums vs. Other Data Types

1. Why are enums considered type-safe compared to integer constants?

2. In which scenario would using an enum be inappropriate?

3. What happens if you try to assign an invalid value to an enum variable?

Enums vs. Other Data Types

1. Why are enums considered type-safe compared to integer constants?

2. In which scenario would using an enum be inappropriate?

3. What happens if you try to assign an invalid value to an enum variable?