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📜  Java中的 ConcurrentSkipListSet pollLast() 方法

📅  最后修改于: 2022-05-13 01:55:45.272000             🧑  作者: Mango

Java中的 ConcurrentSkipListSet pollLast() 方法

Java .util.concurrent.ConcurrentSkipListSetpollLast()方法是Java中的一个内置函数,它返回检索并删除最后一个(最高)元素,如果此集合为空,则返回 null。

句法:

public E pollLast()

返回值:该函数返回检索并删除最后一个(最高)元素,如果此集合为空,则返回 null。

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

方案一:

// Java program to demonstrate pollLast()
// method of ConcurrentSkipListSet
  
import java.util.concurrent.*;
  
class ConcurrentSkipListSetpollLastExample1 {
    public static void main(String[] args)
    {
        // Creating a set object
        ConcurrentSkipListSet Lset = new ConcurrentSkipListSet();
  
        // Adding elements to this set
        for (int i = 10; i <= 50; i += 10)
            Lset.add(i);
  
        // Printing the content of the set
        System.out.println("Contents of the set: " + Lset);
  
        // Retrieving and removing Last element of the set
        System.out.println("The Last element of the set: " + Lset.pollLast());
  
        // Printing the content of the set after pollLast()
        System.out.println("Contents of the set after pollLast: " + Lset);
    }
}
输出:
Contents of the set: [10, 20, 30, 40, 50]
The Last element of the set: 50
Contents of the set after pollLast: [10, 20, 30, 40]

方案二:

// Java program to demonstrate pollLast()
// method of ConcurrentSkipListSet
  
import java.util.concurrent.*;
  
class ConcurrentSkipListSetpollLastExample2 {
    public static void main(String[] args)
    {
        // Creating a set object
        ConcurrentSkipListSet Lset = new ConcurrentSkipListSet();
  
        // Printing the content of the set
        System.out.println("Contents of the set: " + Lset);
  
        // Retrieving and removing Last element of the set
        System.out.println("The Last element of the set: " + Lset.pollLast());
    }
}
输出:
Contents of the set: []
The Last element of the set: null

参考:
https://docs.oracle.com/javase/8/docs/api/java Java