Java BlockingDeque putFirst()用法及代碼示例

BlockingDeque的putFirst(E e)方法將指定元素插入此雙端隊列表示的隊列的開頭。如果Deque受容量限製，則它將等待空間可用。

用法:

public void putFirst(E e)

參數：此方法接受強製參數e，該參數是要在BlockingDeque前麵插入的元素。

返回值：此方法不返回任何內容。

異常：該程序將引發兩個異常，如下所示：

NullPointerException –如果指定的元素為null
InterruptedException–如果在等待時被打斷

注意：BlockingDeque的putFirst()方法已從Java中的LinkedBlockingDeque類繼承。

以下示例程序旨在說明BlockingDeque的putFirst()方法：

示例1:

// Java Program Demonstrate putFirst() 
// 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.putFirst(7855642); 
        BD.putFirst(35658786); 
        BD.putFirst(5278367); 
        BD.putFirst(74381793); 
  
        // print Deque 
        System.out.println("Blocking Deque: " + BD); 
    } 
}

輸出：

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

示例2:

// Java Program Demonstrate putFirst() 
// method of BlockingDeque 
// throwing NullPointerException 
  
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.putFirst(7855642); 
        BD.putFirst(35658786); 
        BD.putFirst(5278367); 
  
        // throws an exception 
        BD.putFirst(null); 
  
        // print Dequeue 
        System.out.println("Blocking Deque: " + BD); 
    } 
}

輸出：

Exception in thread "main" java.lang.NullPointerException
    at java.util.concurrent.LinkedBlockingDeque.putFirst(LinkedBlockingDeque.java:373)
    at GFG.main(GFG.java:24)

示例3:

// Java Program Demonstrate putFirst() 
// method of BlockingDeque 
// when capacity exceeded 
  
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>(3); 
  
        // Add numbers to end of BlockingDeque 
        BD.putFirst(7855642); 
        BD.putFirst(35658786); 
        BD.putFirst(5278367); 
  
        // throws an exception 
        BD.putFirst(4356789); 
  
        // print Dequeue 
        System.out.println("Blocking Deque: " + BD); 
    } 
}

輸出：

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

參考： https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#putFirst(E)

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注：本文由純淨天空篩選整理自gopaldave大神的英文原創作品 BlockingDeque putFirst() method in Java with Examples。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。