极客教程Java中的ArrayBlockingQueue take()方法
ArrayBlockingQueue 是有边界的、阻塞的队列，它在内部存储了由数组支持的元素。
- ArrayBlockingQueue 类是Java集合框架的一个成员。
- 有界意味着它将有一个固定的大小，你 不能 存储超过队列容量的元素数量。
- 该队列也遵循FIFO（先进先出）规则来存储和移除队列中的元素。
- 如果你试图把一个元素放入一个满的队列或从一个空的队列中取出一个元素，那么队列将阻止你。
take()方法用于检索和删除该队列的头部。如果队列是空的，那么它将等待，直到一个元素变得可用。
语法
public E take()throws InterruptedException
参数： 该方法不接受任何参数。
返回值： 该方法在该队列的头部返回值。
异常： 如果在等待时被打断，该方法会抛出 InterruptedException 。
下面的程序说明了ArrayBlockingQueue的take()方法。
程序1 :
// Program to demonstrate take() method of ArrayBlockingQueue
import java.util.concurrent.ArrayBlockingQueue;
public class GFG {
public static void main(String[] args)
throws InterruptedException{
// Define capacity of ArrayBlockingQueue
int capacity = 5;
// Create object of ArrayBlockingQueue
ArrayBlockingQueue<Integer> queue =
new ArrayBlockingQueue<Integer>(capacity);
// Add elements to ArrayBlockingQueue
queue.add(23);
queue.add(32);
queue.add(45);
queue.add(12);
// Print queue after adding numbers
System.out.print("After adding numbers Queue: "
+queue);
// Apply take() method
int head=queue.take();
// Print head of queue using take() method
System.out.println("Head of queue removed is "
+head);
System.out.print("After removing head. Queue: ");
System.out.println(queue);
// Apply take() method
head = queue.take();
// Print head of queue using take() method
System.out.println("Head of queue removed is "
+ head);
System.out.print("After removing head. Queue: ");
System.out.println(queue);
}
}
输出
After adding numbers Queue: [23, 32, 45, 12]Head of queue removed is 23
After removing head. Queue: [32, 45, 12]
Head of queue removed is 32
After removing head. Queue: [45, 12]
程序 2:
// Program to demonstrate take() method of ArrayBlockingQueue
import java.util.concurrent.ArrayBlockingQueue;
public class GFG {
// Create a User Object with name
// and age as the attribute
public class User {
public String name;
public String age;
User(String name, String age)
{
this.name = name;
this.age = age;
}
}
// Main Method
public static void main(String[] args)
throws InterruptedException
{
GFG gfg = new GFG();
gfg.takeMethodExample();
}
// Method to give example of take function
public void takeMethodExample()
throws InterruptedException
{
// define capacity of ArrayBlockingQueue
int capacity = 5;
// create object of ArrayBlockingQueue
ArrayBlockingQueue<User> queue =
new ArrayBlockingQueue<User>(capacity);
// create user objects
User user1 = new User("Aman", "24");
User user2 = new User("Amar", "23");
User user3 = new User("Sanjeet", "25");
User user4 = new User("Suvo", "26");
User user5 = new User("Ravi", "22");
// Add Objects to ArrayBlockingQueue
queue.offer(user1);
queue.offer(user2);
queue.offer(user3);
queue.offer(user4);
queue.offer(user5);
// find take() of queue
User head = queue.take();
// print head
System.out.println("Details of User Removed"
+" After Applying take() Method");
System.out.println("User Name : " + head.name);
System.out.println("User Age : " + head.age);
// find take() of queue
head = queue.take();
// print head
System.out.println("Details of User Removed"+
" After Applying take() Method");
System.out.println("User Name : " + head.name);
System.out.println("User Age : " + head.age);
}
}
输出
Details of User Removed After Applying take() Method
User Name : Aman
User Age : 24
Details of User Removed After Applying take() Method
User Name : Amar
User Age : 23
参考资料: https: //docs.oracle.com/javase/7/docs/api/java/util/concurrent/ArrayBlockingQueue.html#take()