Java LinkedBlockingDeque removeFirst()用法及代码示例

LinkedBlockingDeque的removeFirst()方法返回并从中删除Deque容器的第一个元素。如果Deque容器为空，则此方法将引发NoSuchElementException。

用法:

public E removeFirst()

返回值：此方法返回Deque容器的头，这是第一个元素。

异常：如果Deque为空，则该函数将引发NoSuchElementException。

以下示例程序旨在说明LinkedBlockingDeque的removeFirst()方法：

示例1:

// Java Program to demonstrate removeFirst() 
// method of LinkedBlockingDeque 
  
import java.util.concurrent.LinkedBlockingDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InterruptedException 
    { 
  
        // create object of LinkedBlockingDeque 
        LinkedBlockingDeque<Integer> LBD 
            = new LinkedBlockingDeque<Integer>(); 
  
        // Add numbers to end of LinkedBlockingDeque 
        LBD.add(7855642); 
        LBD.add(35658786); 
        LBD.add(5278367); 
        LBD.add(74381793); 
  
        // print Dequee 
        System.out.println("Linked Blocking Deque: " + LBD); 
  
        // removes the front element and prints it 
        System.out.println("First element of Linked Blocking Deque: "
                           + LBD.removeFirst()); 
  
        // prints the Deque 
        System.out.println("Linked Blocking Deque: " + LBD); 
    } 
}

输出：

Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793]

First element of Linked Blocking Deque: 7855642

Linked Blocking Deque: [35658786, 5278367, 74381793]

示例2:

// Java Program to demonstrate removeFirst() 
// method of LinkedBlockingDeque 
  
import java.util.concurrent.LinkedBlockingDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
        throws NoSuchElementException 
    { 
  
        // create object of LinkedBlockingDeque 
        LinkedBlockingDeque<Integer> LBD 
            = new LinkedBlockingDeque<Integer>(); 
  
        // print Dequee 
        System.out.println("Linked Blocking Deque: " + LBD); 
  
        try { 
            // throws an exception 
            LBD.removeFirst(); 
        } 
        catch (Exception e) { 
            System.out.println("Exception when removing "
                               + "first element from this Deque: "
                               + e); 
        } 
    } 
}

输出：

Linked Blocking Deque: []
Exception when removing first element from this Deque: java.util.NoSuchElementException

注：本文由纯净天空筛选整理自 LinkedBlockingDeque removeFirst() method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。