Java BlockingDeque takeFirst()用法及代码示例

BlockingDeque的takeFirst()方法返回并从中删除Deque容器的第一个元素，如有必要，请等待直到某个元素可用为止。如果该方法在等待期间被中断，则该方法将引发InterruptedException。

用法:

public E takeFirst()

返回值：此方法返回Deque容器的第一个元素，如有必要，请等待直到元素可用。

异常：如果函数在等待期间被中断，则该函数将引发InterruptedException。

注意：BlockingDeque的takeFirst()方法已从Java中的LinkedBlockingDeque类继承。

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

示例1:

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

输出：

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

示例2:演示InterruptedException

// Java Program to demonstrate takeFirst() 
// method of BlockingDeque 
  
import java.util.concurrent.LinkedBlockingDeque; 
import java.util.concurrent.BlockingDeque; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
        throws InterruptedException 
    { 
  
        // create object of BlockingDeque 
        BlockingDeque<Integer> BD 
            = new LinkedBlockingDeque<Integer>(); 
  
        // Add numbers to end of BlockingDeque 
        BD.add(7855642); 
        BD.add(35658786); 
        BD.add(5278367); 
        BD.add(74381793); 
  
        // print Dequeue 
        System.out.println("Blocking Deque: " + BD); 
  
        BD.clear(); 
  
        // throws error as the list is empty and it 
        // is interrupted while waiting 
        System.out.println("Head of Blocking Deque: "
                           + BD.takeFirst()); 
    } 
}

运行时错误：

Max real time limit exceeded due to either by heavy load on server or by using sleep function

参考： https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#takeFirst()

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注：本文由纯净天空筛选整理自gopaldave大神的英文原创作品 BlockingDeque takeFirst() method in Java with Examples。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。