Java中的 ConcurrentLinkedDeque descendingIterator() 方法与示例

Java.util.concurrent.ConcurrentLinkedDeque.descendingIterator() 方法用于返回与 ConcurrentLinkedDeque 具有相同元素但顺序相反的迭代器。

句法：

Iterator iterate_value = Array_Deque.descendingIterator();

参数：该方法不带任何参数。

返回值：该方法迭代双端队列的元素并以相反的顺序返回值（迭代器）。

下面的程序说明了Java.util.concurrent.ConcurrentLinkedDeque.descendingIterator() 方法：

方案一：

// Java code to illustrate descendingIterator()
  
import java.util.concurrent.*;
import java.util.*;
  
public class ConcurrentLinkedDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ConcurrentLinkedDeque
        ConcurrentLinkedDeque de_que
            = new ConcurrentLinkedDeque();
  
        // Use add() method to add elements into the Queue
        de_que.add("Welcome");
        de_que.add("To");
        de_que.add("Geeks");
        de_que.add("4");
        de_que.add("Geeks");
  
        // Displaying the ConcurrentLinkedDeque
        System.out.println("ConcurrentLinkedDeque: " + de_que);
  
        // Creating a desc_iterator
        Iterator value = de_que.descendingIterator();
  
        // Displaying the values after iterating
        // through the ConcurrentLinkedDeque
        // in reverse order
        System.out.println("The iterator values are: ");
        while (value.hasNext()) {
            System.out.println(value.next());
        }
    }
}

输出：

ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks]
The iterator values are: 
Geeks
4
Geeks
To
Welcome

方案二：

// Java code to illustrate descendingIterator()
  
import java.util.*;
import java.util.concurrent.*;
  
public class ConcurrentLinkedDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ConcurrentLinkedDeque
        ConcurrentLinkedDeque de_que
            = new ConcurrentLinkedDeque();
  
        // Use add() method to add elements into the Queue
        de_que.add(10);
        de_que.add(15);
        de_que.add(30);
        de_que.add(20);
        de_que.add(5);
  
        // Displaying the ConcurrentLinkedDeque
        System.out.println("ConcurrentLinkedDeque: " + de_que);
  
        // Creating a desc_iterator
        Iterator value = de_que.descendingIterator();
  
        // Displaying the values after iterating
        // through the ConcurrentLinkedDeque
        // in reverse order
        System.out.println("The iterator values are: ");
        while (value.hasNext()) {
            System.out.println(value.next());
        }
    }
}

输出：

ConcurrentLinkedDeque: [10, 15, 30, 20, 5]
The iterator values are: 
5
20
30
15
10