Java 中 LinkedBlockingDeque putFirst()方法

原文:https://www . geeksforgeeks . org/link edblockingeque-put first-in-method-Java/

的 putFirst(E e) 方法链接锁定队列将指定的元素插入到这个队列所代表的队列的前面。如果德奎是容量受限的，那么它将等待空间变得可用。

语法:

public void putFirst(E e)

参数:该方法接受一个强制参数 e ，它是要插入到链接锁定请求前面的元素。

返回:此方法不返回任何内容。

异常:程序抛出如下所示的两个异常:

  • null pointerexception -If the specified element is empty
  • Interrupt exception –If you interrupt while waiting

下面的程序说明了链接锁定请求的 putFirst()方法:

程序 1:

// Java Program Demonstrate putFirst()
// 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.putFirst(7855642);
        LBD.putFirst(35658786);
        LBD.putFirst(5278367);
        LBD.putFirst(74381793);

        // print Dequeue
        System.out.println("Linked Blocking Deque: " + LBD);
    }
}

输出:

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

节目 2:

// Java Program Demonstrate putFirst()
// method of LinkedBlockingDeque
// throwing NullPointerException

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.putFirst(7855642);
        LBD.putFirst(35658786);
        LBD.putFirst(5278367);

        // throws an exception
        LBD.putFirst(null);

        // print Dequeue
        System.out.println("Linked Blocking Deque: " + LBD);
    }
}

输出 :

Exception in thread "main" java.lang.NullPointerException
    at java.util.concurrent.LinkedBlockingDeque.putFirst(LinkedBlockingDeque.java:373)
    at GFG.main(GFG.java:23)

节目 3:

// Java Program Demonstrate putFirst()
// method of LinkedBlockingDeque
// when capacity exceeded

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>(3);

        // Add numbers to end of LinkedBlockingDeque
        LBD.putFirst(7855642);
        LBD.putFirst(35658786);
        LBD.putFirst(5278367);

        // throws an exception
        LBD.putFirst(4356789);

        // print Dequeue
        System.out.println("Linked Blocking Deque: " + LBD);
    }
}

输出 :

Runtime Errors:
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/8/docs/API/Java/util/concurrent/linkedblockingrequest . html # putFirst-E-

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