Java中EnumSet的copyOf()方法: Java.util.EnumSet.copyOf()

// Java program to demonstrate copyOf() method
import java.util.*;
 
// Creating an enum of GFG type
enum GFG {
    Welcome,
    To,
    The,
    World,
    of,
    Geeks
}
;
 
public class Enum_Set_Demo {
 
    public static void main(String[] args)
    {
 
        // Creating an empty collection
        Collection collect = new ArrayList();
 
        // Adding elements to the Collection
        collect.add(GFG.Welcome);
        collect.add(GFG.World);
        collect.add(GFG.Geeks);
 
        // Displaying the collection
        System.out.println("The collection is: " + collect);
 
        EnumSet e_set = EnumSet.copyOf(collect);
 
        // Displaying the final set
        System.out.println("The enum set is:" + e_set);
    }
}

输出：

The collection is: [Welcome, World, Geeks]
The enum set is:[Welcome, World, Geeks]

// Java program to demonstrate copyOf() method
import java.util.*;

// Creating an enum of CARS type
enum CARS {
????RANGE_ROVER,
????MUSTANG,
????CAMARO,
????AUDI,
????BMW
}
;

public class Enum_Set_Demo {

????public static void main(String[] args)
????{

????????// Creating an empty EnumSet
????????// Getting all elements from CARS
????????EnumSet e_set = EnumSet.allOf(CARS.class);???????

????????// Displaying the initial EnumSet
????????System.out.println("Initial set is: " + e_set);

????????// Copying the set
????????EnumSet new_set = EnumSet.copyOf(e_set);

????????// Displaying the final set
????????System.out.println("The new set is: " + new_set);
????}
}

输出：

Initial set is: [RANGE_ROVER, MUSTANG, CAMARO, AUDI, BMW]
The new set is: [RANGE_ROVER, MUSTANG, CAMARO, AUDI, BMW]