Java 中的 concurrentlinkedequepoll()方法，示例
原文:https://www . geeksforgeeks . org/concurrentlinkedeque-poll-method-in-Java-with-example/
的 poll() 方法 concurrentlinkedeque返回 Deque 容器中的 front 元素并删除它。如果容器是空的，它将返回空值。
语法:
public E poll()
参数:此方法不接受任何参数。
返回:如果容器不是空的，这个方法返回前元素并删除它。如果容器是空的，它将返回空值。
以下程序说明了并发链接请求的轮询()方法:
程序 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);
}
}
Output:
ConcurrentLinkedDeque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: 7855642
ConcurrentLinkedDeque: [35658786, 5278367, 74381793]
程序 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());
}
}
Output:
ConcurrentLinkedDeque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: null
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