Java ConcurrentSkipListSet pollLast()用法及代碼示例

java.util.concurrent.ConcurrentSkipListSet的pollLast()方法是Java中的一個內置函數，該函數返回檢索並刪除最後一個(最高)元素，如果此集為空，則返回null。

用法:

public E pollLast()

返回值：該函數返回以檢索並刪除最後一個(最高)元素，如果此集合為空，則返回null。

以下示例程序旨在說明ConcurrentSkipListSet.pollLast()方法：

示例1:

// 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<Integer> Lset = new ConcurrentSkipListSet<Integer>(); 
  
        // 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); 
    } 
}

輸出：

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]

示例2:

// 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<Integer> Lset = new ConcurrentSkipListSet<Integer>(); 
  
        // 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()); 
    } 
}

輸出：

Contents of the set: []
The Last element of the set: null

參考：
https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentSkipListSet.html#pollLast–

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注：本文由純淨天空篩選整理自rupesh_rao大神的英文原創作品 ConcurrentSkipListSet pollLast() method in Java。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。