Java LinkedBlockingDeque getLast()方法

LinkedBlockingDeque 的 getLast() 方法返回Deque容器中的最后一个元素。如果LinkedBlockingDeque是空的，那么在调用该方法时，会返回一个NoSuchElementException。

语法

public E getLast()

参数： 该方法不接受任何参数。

返回： 该方法返回该Deque容器的最后一个元素。

异常： 该函数只抛出一个异常，即当deque为空时， NoSuchElementException 。

下面的程序说明了LinkedBlockingDeque的getLast()方法。

程序1 :

// Java Program Demonstrate getLast()
// method of LinkedBlockingDeque
  
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of LinkedBlockingDeque
        LinkedBlockingDeque<Integer> LBD
            = new LinkedBlockingDeque<Integer>();
  
        // Add numbers to front of LinkedBlockingDeque
        LBD.addFirst(7855642);
        LBD.addFirst(35658786);
        LBD.addFirst(5278367);
        LBD.addFirst(74381793);
  
        // before removing print queue
        System.out.println("Linked Blocking Deque: " + LBD);
  
        // prints the last element
        System.out.println("Linked Blocking Deque first element: " +
                                                     LBD.getLast());
    }
}

输出:

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

示例2

// Java Program Demonstrate getLast()
// method of LinkedBlockingDeque
// shows exception
  
import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
        throws IllegalStateException
    {
  
        // create object of LinkedBlockingDeque
        LinkedBlockingDeque<Integer> LBD
            = new LinkedBlockingDeque<Integer>();
  
        // Add numbers to front of LinkedBlockingDeque
        LBD.addFirst(7855642);
        LBD.addFirst(35658786);
        LBD.addFirst(5278367);
        LBD.addFirst(74381793)
  
            LBD.clear();
  
        // Since the container is empty it will throw exception
        System.out.println("Linked Blocking Deque first element: " + 
                                                     LBD.getLast());
    }
}

输出

Exception in thread "main" java.util.NoSuchElementException
    at java.util.concurrent.LinkedBlockingDeque.getLast(LinkedBlockingDeque.java:553)
    at GFG.main(GFG.java:28)

参考资料: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedBlockingDeque.html#getLast()