Java LinkedBlockingQueue iterator()方法

LinkedBlockingQueue的 iterator() 方法返回一个与此LinkedBlockingQueue相同的元素的迭代器，并以适当的顺序排列。从这个方法返回的元素包含了所有的元素，其顺序是从LinkedBlockingQueue的 第一个（head） 到 最后一个（tail） 。返回的迭代器是弱一致性的。

语法：

public Iterator<E> iterator()

返回值： 该方法返回迭代器，其元素与LinkedBlockingQueue中的元素相同，顺序为从头（head）到尾（tail）。
下面的程序说明了LinkedBlockingQueue类的迭代器（）方法：

程序1： 从LinkedBlockingQueue中创建一个迭代器，其中包含一个类中不同学生的名字。

// Java Program Demonstrate iterator()
// method of LinkedBlockingQueue
 
import java.util.concurrent.LinkedBlockingQueue;
import java.util.Iterator;
 
public class GFG {
 
    public static void main(String[] args)
    {
        // define capacity of LinkedBlockingQueue
        int capacityOfQueue = 7;
 
        // create object of LinkedBlockingQueue
        LinkedBlockingQueue<String> linkedQueue
            = new LinkedBlockingQueue<String>(capacityOfQueue);
 
        // Add element to LinkedBlockingQueue
        linkedQueue.add("John");
        linkedQueue.add("Tom");
        linkedQueue.add("Clark");
        linkedQueue.add("Kat");
 
        // create Iterator of linkedQueue using iterator() method
        Iterator<String> listOfNames = linkedQueue.iterator();
 
        // print result
        System.out.println("list of names:");
        while (listOfNames.hasNext())
            System.out.println(listOfNames.next());
    }
}

输出

list of names:
John
Tom
Clark
Kat

程序2： 从包含雇员列表的LinkedBlockingQueue中创建一个Iterator。

// Java Program Demonstrate iterator()
// method of LinkedBlockingQueue
 
import java.util.concurrent.LinkedBlockingQueue;
import java.util.Iterator;
 
public class GFG {
 
    public void collectIterator()
    {
        // define capacity of LinkedBlockingQueue
        int capacityOfQueue = 7;
 
        // create object of LinkedBlockingQueue
        LinkedBlockingQueue<Employee> linkedQueue
            = new LinkedBlockingQueue<Employee>(capacityOfQueue);
 
        // Add element to LinkedBlockingQueue
        Employee emp1 = new Employee("Sachin", "Developer", "39000");
        Employee emp2 = new Employee("Sanjeev", "Tester", "26000");
 
        // Add Employee Objects to linkedQueue
        linkedQueue.add(emp1);
        linkedQueue.add(emp2);
 
        // create Iterator of linkedQueue using iterator() method
        Iterator<Employee> listOfEmployee = linkedQueue.iterator();
 
        // print result from iterator
        System.out.println("list of Employees:");
        while (listOfEmployee.hasNext()) {
            System.out.println("*************************");
            Employee emp = listOfEmployee.next();
            System.out.println("Employee Name : " + emp.name);
            System.out.println("Employee Position : " + emp.position);
            System.out.println("Employee Salary : " + emp.salary);
        }
    }
 
    // create an Employee Object with name,
    // position and salary as an attribute
    public class Employee {
 
        public String name;
        public String position;
        public String salary;
 
        Employee(String name, String position, String salary)
        {
            this.name = name;
            this.position = position;
            this.salary = salary;
        }
 
        @Override
        public String toString()
        {
            return "Employee [name=" + name + ", position="
                + position + ", salary=" + salary + "]";
        }
    }
 
    // Main Method
    public static void main(String[] args)
    {
        GFG gfg = new GFG();
        gfg.collectIterator();
    }
}

输出

list of Employees:
*************************
Employee Name : Sachin
Employee Position : Developer
Employee Salary : 39000
*************************
Employee Name : Sanjeev
Employee Position : Tester
Employee Salary : 26000

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