[Java] 编程思想 - 枚举类型

向 enum里面添加类型

public enum OzWitch {
    WEST("Miss Gulch, aka Dorothy's Auntie Em", "Munchkins"),
    NORTH("Glenda the Good Witch", "Gillikins"),
    EAST("Evloc, aka the Wicked Witch of the East", "Winkies"),
    SOUTH("Locasta, aka the Good Witch of the South", "Quadlings");

    private final String description;
    private final String inhabitants;

    private OzWitch(String description, String inhabitants) {
        this.description = description;
        this.inhabitants = inhabitants;
    }
    public String getDescription() {
        return description;
    }
    public static void main(String[] args) {
        for (OzWitch witch : OzWitch.values()) {
            System.out.println(witch + ": " + witch.getDescription() + ", " + witch.inhabitants);
        }
    }
}

覆盖enum的toString的方法

public enum SpaceShip {
    SCOUT, CARGO, TRANSPORT, BATTLE;
    public String toString() {
        String id = name();
        String lower = id.substring(1).toLowerCase();
        return id.charAt(0) + lower;
    }
    public static void main(String[] args) {
        for (SpaceShip s : SpaceShip.values()) {
            System.out.println(s);
        }
    }
}

Switch中使用enum

enum Signal {
    RED, GREEN, YELLOW
}
public class TrafficLight {
    Signal color = Signal.RED;
    public void change() {
        switch (color) {
            case RED -> color = Signal.GREEN;
            case GREEN -> color = Signal.YELLOW;
            case YELLOW -> color = Signal.RED;
        }
    }
    public String toString() {
        return "The traffic light is " + color;
    }
    public static void main(String[] args) {
        TrafficLight light = new TrafficLight();
        for (int i = 0; i < 7; i++) {
            System.out.println(light);
            light.change();
        }
    }
}

BigEnumSet 使用方式

import java.util.EnumSet;

public class BigEnumSet {
    // Class implementation goes here
    enum Big {
        A0, A1, A2, A3, A4, A5, A6, A7, A8, A9,
        A10, A11, A12, A13, A14, A15, A16, A17, A18, A19,
        A20, A21, A22, A23, A24, A25, A26, A27, A28, A29,
        A30, A31, A32, A33, A34, A35, A36, A37, A38, A39,
        A40, A41, A42, A43, A44, A45, A46, A47, A48, A49,
        A50, A51, A52, A53, A54, A55, A56, A57, A58, A59,
        A60, A61, A62, A63, A64, A65, A66, A67, A68, A69,
        A70, A71, A72, A73, A74, A75
    }
    public static void main(String[] args) {
        EnumSet<Big> bigEnumSet = EnumSet.allOf(Big.class);
        System.out.println("BigEnumSet contains: " + bigEnumSet);
    }
}