public enum Season {
    SPRING, SUMMER, AUTUMN, WINTER
}

public enum Season {
    SPRING(1), SUMMER(2), AUTUMN(3), WINTER(4);
    private final int value;
    Season(int value) {
        this.value = value;
    }
    public int getValue() {
        return value;
    }
}

public enum Season {
    SPRING(1), SUMMER(2), AUTUMN(3), WINTER(4);
    private final int value;
    Season(int value) {
        this.value = value;
    }
    public int getValue() {
        return value;
    }
}
public class EnumDemo {
    public static void main(String[] args) {
        // 1. 直接引用枚舉常量
        Season spring = Season.SPRING;
        System.out.println(spring);  // 輸出: SPRING
        // 2. 獲取枚舉的名稱
        String name = spring.name();
        System.out.println(name);    // 輸出: SPRING
        // 3. 獲取枚舉的序號(hào)
        int ordinal = spring.ordinal();
        System.out.println(ordinal); // 輸出: 0
        // 4. 獲取枚舉的自定義值
        int value = spring.getValue();
        System.out.println(value);   // 輸出: 1
        // 5. 獲取所有枚舉常量
        Season[] seasons = Season.values();
        for (Season s : seasons) {
            System.out.println(s);   // 輸出: SPRING, SUMMER, AUTUMN, WINTER
        }
        // 6. 字符串轉(zhuǎn)換為枚舉
        Season summer = Season.valueOf("SUMMER");
        System.out.println(summer);  // 輸出: SUMMER
        // 注意：valueOf區(qū)分大小寫，如果找不到匹配的枚舉常量會(huì)拋出IllegalArgumentException
        try {
            Season.valueOf("spring"); // 會(huì)拋出異常
        } catch (IllegalArgumentException e) {
            System.out.println("枚舉常量不存在");
        }
    }
}

public class EnumCompareDemo {
    public static void main(String[] args) {
        Season spring = Season.SPRING;
        Season summer = Season.SUMMER;
        // 1. 使用 == 比較（推薦）
        // 因?yàn)槊杜e常量是單例的，所以可以直接使用==比較
        boolean isEqual = (spring == Season.SPRING);    // true
        System.out.println("使用==比較：" + isEqual);
        // 2. 使用 equals() 比較
        // equals方法和==效果相同，但是更耗性能
        boolean isEqualUsingEquals = spring.equals(Season.SPRING);    // true
        System.out.println("使用equals比較：" + isEqualUsingEquals);
        // 3. 使用 compareTo() 比較順序
        // 根據(jù)枚舉定義的順序比較，返回差值
        int compareResult = spring.compareTo(summer);    // -1 (因?yàn)镾PRING在SUMMER前面)
        System.out.println("使用compareTo比較：" + compareResult);
        // 4. switch語句中使用枚舉
        switch (spring) {
            case SPRING:
                System.out.println("春天");
                break;
            case SUMMER:
                System.out.println("夏天");
                break;
            case AUTUMN:
                System.out.println("秋天");
                break;
            case WINTER:
                System.out.println("冬天");
                break;
        }
        // 5. 在集合中使用枚舉
        Set<Season> seasonSet = EnumSet.of(Season.SPRING, Season.SUMMER);
        System.out.println("EnumSet：" + seasonSet);  // 輸出: [SPRING, SUMMER]
        Map<Season, String> seasonMap = EnumMap<Season, String>(Season.class);
        seasonMap.put(Season.SPRING, "春天");
        System.out.println("EnumMap：" + seasonMap);  // 輸出: {SPRING=春天}
    }
}

public interface Describable {
    String getDescription();
}
public enum Season implements Describable {
    SPRING("春暖花開"),
    SUMMER("驕陽似火"),
    AUTUMN("秋高氣爽"),
    WINTER("白雪皚皚");
    private final String description;
    Season(String description) {
        this.description = description;
    }
    @Override
    public String getDescription() {
        return description;
    }
}

public enum Operation {
    PLUS {
        public double apply(double x, double y) { return x + y; }
    },
    MINUS {
        public double apply(double x, double y) { return x - y; }
    };
    public abstract double apply(double x, double y);
}

public enum OrderStatus {
    CREATED, PAID, SHIPPED, DELIVERED, CANCELLED;
    public boolean canTransitionTo(OrderStatus newStatus) {
        switch (this) {
            case CREATED:
                return newStatus == PAID || newStatus == CANCELLED;
            case PAID:
                return newStatus == SHIPPED || newStatus == CANCELLED;
            case SHIPPED:
                return newStatus == DELIVERED;
            default:
                return false;
        }
    }
}

public enum PaymentType {
    ALIPAY {
        @Override
        public void pay(BigDecimal amount) {
            // 支付寶支付邏輯
        }
    },
    WECHAT {
        @Override
        public void pay(BigDecimal amount) {
            // 微信支付邏輯
        }
    };
    public abstract void pay(BigDecimal amount);
}

public enum Singleton {
    INSTANCE;
    private String data;
    public String getData() {
        return data;
    }
    public void setData(String data) {
        this.data = data;
    }
}

public enum ErrorCode {
    SUCCESS(0, "操作成功"),
    PARAM_ERROR(400, "參數(shù)錯(cuò)誤"),
    UNAUTHORIZED(401, "未授權(quán)"),
    FORBIDDEN(403, "禁止訪問"),
    NOT_FOUND(404, "資源不存在"),
    INTERNAL_ERROR(500, "服務(wù)器內(nèi)部錯(cuò)誤");
    private final int code;
    private final String message;
    ErrorCode(int code, String message) {
        this.code = code;
        this.message = message;
    }
    public int getCode() {
        return code;
    }
    public String getMessage() {
        return message;
    }
}

public enum DatabaseType {
    MYSQL("com.mysql.jdbc.Driver", "jdbc:mysql://"),
    ORACLE("oracle.jdbc.driver.OracleDriver", "jdbc:oracle:thin:@"),
    POSTGRESQL("org.postgresql.Driver", "jdbc:postgresql://");
    private final String driverClass;
    private final String urlPrefix;
    DatabaseType(String driverClass, String urlPrefix) {
        this.driverClass = driverClass;
        this.urlPrefix = urlPrefix;
    }
    public String getDriverClass() {
        return driverClass;
    }
    public String getUrlPrefix() {
        return urlPrefix;
    }
}