Java中的 ConcurrentSkipListSet contains() 方法

Java .util.concurrent.ConcurrentSkipListSet的contains()方法是Java中的一个内置函数，如果指定元素存在于此集合中，则返回 true 布尔值，否则返回 false。

句法：

ConcurrentSkipListSet.contains(Object o)

参数：该函数接受单个参数，即检查该参数是否存在。

返回值：函数返回一个布尔值。如果此集合中存在指定的元素，则返回 True，否则返回 False。

下面的程序说明了 ConcurrentSkipListSet.contains() 方法：

方案一：

// Java Program Demonstrate contains()
// method of ConcurrentSkipListSet
  
import java.util.concurrent.*;
  
class ConcurrentSkipListSetContainsExample1 {
    public static void main(String[] args)
    {
  
        // Initializing the set
        ConcurrentSkipListSet
            set = new ConcurrentSkipListSet();
  
        // Adding elements to this set
        for (int i = 10; i <= 15; i++)
            set.add(i);
  
        // Checks if 9 is present in the set
        if (set.contains(9))
            System.out.println("9 is present in the set.");
        else
            System.out.println("9 is not present in the set.");
    }
}

输出：

9 is not present in the set.

方案二：

// Java Program Demonstrate contains()
// method of ConcurrentSkipListSet */
  
import java.util.concurrent.*;
  
class ConcurrentSkipListSetContainsExample2 {
    public static void main(String[] args)
    {
  
        // Initializing the set
        ConcurrentSkipListSet
            set = new ConcurrentSkipListSet();
  
        // Adding elements to this set
        set.add("Gfg");
        set.add("is");
        set.add("fun");
  
        // Checks if Gfg is present in the set
        if (set.contains("Gfg"))
            System.out.println("Gfg is present in the set.");
        else
            System.out.println("Gfg is not present in the set.");
    }
}

输出：

Gfg is present in the set.

参考：https: Java/util/concurrent/ConcurrentSkipListSet.html#contains-java.lang.Object-