Java ArrayBlockingQueue iterator()方法

ArrayBlockingQueue 类的 iterator() 方法是用来返回一个与该队列相同的元素的迭代器，并以适当的顺序。从这个方法返回的元素包含了从第一个（head）到最后一个（tail）的顺序。返回的迭代器是弱一致性的。

语法

public Iterator iterator()

返回值： 该方法返回具有与ArrayBlockingQueue中的元素相同的顺序的迭代器。

下面的程序说明了ArrayBlockingQueue类的iterator()方法。

程序1 :

// Program Demonstrate how to apply iterator() method
// of ArrayBlockingQueue Class.
  
import java.util.concurrent.ArrayBlockingQueue;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Define capacity of ArrayBlockingQueue
        int capacity = 5;
  
        // Create object of ArrayBlockingQueue
        ArrayBlockingQueue<Integer> queue = new 
                ArrayBlockingQueue<Integer>(capacity);
  
        // Add 5 elements to ArrayBlockingQueue
        queue.offer(423);
        queue.offer(422);
        queue.offer(421);
        queue.offer(420);
        queue.offer(424);
  
        // Print queue
        System.out.println("Queue is " + queue);
  
        // Call iterator() method and Create an iterator
        Iterator iteratorValues = queue.iterator();
  
        // Print elements of iterator
        System.out.println("\nThe iterator values:");
        while (iteratorValues.hasNext()) {
            System.out.println(iteratorValues.next());
        }
    }
}

输出。

Queue is [423, 422, 421, 420, 424]

The iterator values:
423
422
421
420
424

程序2

// Program Demonstrate how to apply iterator() method
// of ArrayBlockingQueue Class.
  
import java.util.concurrent.ArrayBlockingQueue;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Define capacity of ArrayBlockingQueue
        int capacity = 5;
  
        // Create object of ArrayBlockingQueue
        ArrayBlockingQueue<String> queue = new 
                  ArrayBlockingQueue<String>(capacity);
  
        // Add 5 elements to ArrayBlockingQueue
        queue.offer("User");
        queue.offer("Employee");
        queue.offer("Manager");
        queue.offer("Analyst");
        queue.offer("HR");
  
        // Print queue
        System.out.println("Queue is " + queue);
  
        // Call iterator() method and Create an iterator
        Iterator iteratorValues = queue.iterator();
  
        // Print elements of iterator
        System.out.println("\nThe iterator values:");
        while (iteratorValues.hasNext()) {
            System.out.println(iteratorValues.next());
        }
    }
}

输出。

Queue is [User, Employee, Manager, Analyst, HR]

The iterator values:
User
Employee
Manager
Analyst
HR

参考资料: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ArrayBlockingQueue.html#iterator