Java中的 CopyOnWriteArraySet containsAll() 方法及示例

Java CopyOnWriteArraySet的containsAll()方法用于检查两个集合是否包含相同的元素。它将一个集合作为参数，如果该集合的所有元素都存在于另一个集合中，则返回 True。

句法：

public boolean containsAll(Collection C)

参数：参数C是一个集合。该参数是指需要在该集合中检查其元素出现的集合。

返回值：如果该集合包含其他集合的所有元素，则该方法返回 True，否则返回 False。

下面的程序说明了 CopyOnWriteArraySet.containsAll() 方法：

方案一：

// Java code to illustrate
// CopyOnWriteArraySet containsAll()
  
import java.util.*;
import java.util.concurrent.*;
  
class StackDemo {
    public static void main(String args[])
    {
  
        // Creating an empty set
        CopyOnWriteArraySet
            set = new CopyOnWriteArraySet();
  
        // Use add() method to
        // add elements in the set
        set.add("Geeks");
        set.add("for");
        set.add("Geeks");
        set.add("10");
        set.add("20");
  
        // prints the set
        System.out.println("CopyOnWriteArraySet 1: "
                           + set);
  
        // Creating another empty set
        CopyOnWriteArraySet
            set2 = new CopyOnWriteArraySet();
  
        // Use add() method to
        // add elements in the set
        set2.add("Geeks");
        set2.add("for");
        set2.add("Geeks");
        set2.add("10");
        set2.add("20");
  
        // prints the set
        System.out.println("CopyOnWriteArraySet 2: "
                           + set2);
  
        // Check if the set
        // contains same elements
        System.out.println("\nDoes set 1 contains set 2: "
                           + set.containsAll(set2));
    }
}

输出：

CopyOnWriteArraySet 1: [Geeks, for, 10, 20]
CopyOnWriteArraySet 2: [Geeks, for, 10, 20]

Does set 1 contains set 2: true

输出：

CopyOnWriteArraySet 1: [Geeks, for, Geeks, 10, 20]
CopyOnWriteArraySet 2: [Geeks, for, Geeks, 10, 20]

Does set 1 contains set 2: true

方案二：

// Java code to illustrate boolean containsAll()
  
import java.util.*;
import java.util.concurrent.*;
  
class StackDemo {
    public static void main(String args[])
    {
  
        // Creating an empty set
        CopyOnWriteArraySet
            set = new CopyOnWriteArraySet();
  
        // Use add() method to
        // add elements in the set
        set.add("Geeks");
        set.add("for");
        set.add("Geeks");
  
        // prints the set
        System.out.println("CopyOnWriteArraySet 1: "
                           + set);
  
        // Creating another empty set
        CopyOnWriteArraySet
            set2 = new CopyOnWriteArraySet();
  
        // Use add() method to
        // add elements in the set
        set2.add("10");
        set2.add("20");
  
        // prints the set
        System.out.println("CopyOnWriteArraySet 2: "
                           + set2);
  
        // Check if the set
        // contains same elements
        System.out.println("\nDoes set 1 contains set 2: "
                           + set.containsAll(set2));
    }
}

输出：

CopyOnWriteArraySet 1: [Geeks, for]
CopyOnWriteArraySet 2: [10, 20]

Does set 1 contains set 2: false