Java ConcurrentLinkedDeque poll()用法及代碼示例

ConcurrentLinkedDeque的poll()方法返回Deque容器中的front元素並將其刪除。如果容器為空，則返回null。

用法:

public E poll()

參數：此方法不接受任何參數。

返回值：如果容器不為空，則此方法返回Deque容器的front元素並將其刪除。如果容器為空，則返回null。

以下示例程序旨在說明ConcurrentLinkedDeque的poll()方法：

示例1:

// Java Program Demonstrate poll() 
// method of ConcurrentLinkedDeque 
  
import java.util.concurrent.ConcurrentLinkedDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
  
    { 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<Integer> CLD 
            = new ConcurrentLinkedDeque<Integer>(); 
  
        // Add numbers to end of ConcurrentLinkedDeque 
        CLD.add(7855642); 
        CLD.add(35658786); 
        CLD.add(5278367); 
        CLD.add(74381793); 
  
        // Print the queue 
        System.out.println("ConcurrentLinkedDeque: "
                           + CLD); 
  
        System.out.println("Front element in Deque: "
                           + CLD.poll()); 
  
        // One element is deleted as poll was called 
        System.out.println("ConcurrentLinkedDeque: "
                           + CLD); 
    } 
}

輸出：

ConcurrentLinkedDeque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: 7855642
ConcurrentLinkedDeque: [35658786, 5278367, 74381793]

示例2:

// Java Program Demonstrate poll() 
// method of ConcurrentLinkedDeque 
// when Deque is empty 
  
import java.util.concurrent.ConcurrentLinkedDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
  
    { 
  
        // create object of ConcurrentLinkedDeque 
        ConcurrentLinkedDeque<Integer> CLD 
            = new ConcurrentLinkedDeque<Integer>(); 
  
        // Add numbers to end of ConcurrentLinkedDeque 
        CLD.add(7855642); 
        CLD.add(35658786); 
        CLD.add(5278367); 
        CLD.add(74381793); 
  
        // Print the queue 
        System.out.println("ConcurrentLinkedDeque: "
                           + CLD); 
  
        // empty deque 
        CLD.clear(); 
  
        System.out.println("Front element in Deque: "
                           + CLD.poll()); 
    } 
}

輸出：

ConcurrentLinkedDeque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: null

相關用法

注：本文由純淨天空篩選整理自MerlynShelley大神的英文原創作品 ConcurrentLinkedDeque poll() method in Java with Example。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。