线程安全的枚举单例(Thread-safe Enum Singleton)

 枚举适合创建单例。 我知道枚举方法不是线程安全的，所以我试着让它成为线程安全的。 任何人都可以确认这种实施是否正确。 使用静态和易变的这么多地方是否可以，并且可以优化？ 由于内部类是私有的，因此我必须在枚举中创建函数以访问内部类功能。 可以优化吗？ 
 
import java.util.Date;

public enum SingletonWithEnum {
    INSTANCE;   

    private static class Singleton{

        private static volatile int count;
        private static volatile Date date;      

        public static  int getCount() { return count;}

        public static void setCount(int countParam) { synchronized(Singleton.class){ count = countParam; }}

        public static Date getDate() {  return date;}

        public static void setDate(Date dateParam) { synchronized(Singleton.class){ date = dateParam;}}

        public static String printObject() {
            return "Singleton [count=" + getCount() + ", date=" + getDate() + "]";
        }

    }

    public int getCount() { return Singleton.getCount();}

    public void setCount(int countParam)    {Singleton.setCount(countParam);}

    public Date getDate() { return Singleton.getDate();}

    public void setDate(Date dateParam) {Singleton.setDate(dateParam);}

    public String toString(){return Singleton.printObject();}
};
 
 我正在使用它。 
 
SingletonWithEnum object1 = SingletonWithEnum.INSTANCE;
object1.setCount(5);
object1.setDate(new Date());

Enums are good for creating singleton. I know enum methods are not thread-safe so I tried to make it thread-safe. Can anyone please confirm if this implementation is correct or not. Is it fine to use static and volatile so many places and can it be optimized? As inner class is private so I have to create functions in enum to access inner class functionality. Can it be optimized?
 
import java.util.Date;

public enum SingletonWithEnum {
    INSTANCE;   

    private static class Singleton{

        private static volatile int count;
        private static volatile Date date;      

        public static  int getCount() { return count;}

        public static void setCount(int countParam) { synchronized(Singleton.class){ count = countParam; }}

        public static Date getDate() {  return date;}

        public static void setDate(Date dateParam) { synchronized(Singleton.class){ date = dateParam;}}

        public static String printObject() {
            return "Singleton [count=" + getCount() + ", date=" + getDate() + "]";
        }

    }

    public int getCount() { return Singleton.getCount();}

    public void setCount(int countParam)    {Singleton.setCount(countParam);}

    public Date getDate() { return Singleton.getDate();}

    public void setDate(Date dateParam) {Singleton.setDate(dateParam);}

    public String toString(){return Singleton.printObject();}
};
 
I am using it like this.
 
SingletonWithEnum object1 = SingletonWithEnum.INSTANCE;
object1.setCount(5);
object1.setDate(new Date());

原文：https://stackoverflow.com/questions/28369025