Java 中 BlockingQueue take()方法示例
原文:https://www . geeksforgeeks . org/blocking queue-take-method-in-Java-with-examples/
阻塞队列接口的 take() 方法用于检索和删除该队列的头。如果队列是空的，那么它将等待直到一个元素变得可用。如果在线程上工作并在该进程中使用阻塞队列，该方法会更有效。因此，如果没有可用的元素，最初调用 take()的线程将进入睡眠状态，让其他线程做它们需要做的任何事情。
语法:
public E take() throws InterruptedException
返回值:这个方法在这个阻塞队列的头部返回值。如果队列是空的，那么它将等待直到一个元素变得可用。 异常:此方法抛出以下异常:
- 中断异常–如果队列为空，在等待元素变为可用时发生中断。
注:封锁队列的 take() 方法继承了 Java 中的队列类。 以下程序举例说明了 BlockingQueue 接口的 take()方法: 程序 1:
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program Demonstrate take()
// method of BlockingQueue
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.BlockingQueue;
public class GFG {
public static void main(String[] args)
throws InterruptedException
{
// define capacity of BlockingQueue
int capacityOfQueue = 4;
// create object of BlockingQueue
BlockingQueue<String> BQ
= new LinkedBlockingQueue<String>(capacityOfQueue);
// Add element to BlockingQueue
BQ.add("Ravi");
BQ.add("Suraj");
BQ.add("Harsh");
BQ.add("Sayan");
// print elements of queue
System.out.println("Items in Queue are " + BQ);
// remove two elements from queue from head
// Applying take() method on queue to remove element
String removedItem1 = BQ.take();
// print removedItem and queue
System.out.println("Removed Item from head is "
+ removedItem1);
// print elements of queue after removing first item
System.out.println("Remaining Items in Queue are "
+ BQ);
// Applying take() method on queue to remove another element
String removedItem2 = BQ.take();
// print removedItem and queue
System.out.println("Removed Item from head is "
+ removedItem2);
// print elements of queue after removing first item
System.out.println("Remaining Items in Queue are "
+ BQ);
}
}
Output:
Items in Queue are [Ravi, Suraj, Harsh, Sayan]
Removed Item from head is Ravi
Remaining Items in Queue are [Suraj, Harsh, Sayan]
Removed Item from head is Suraj
Remaining Items in Queue are [Harsh, Sayan]
程序 2:
Java 语言(一种计算机语言，尤用于创建网站)
// Java Program Demonstrate take()
// method of BlockingQueue
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.BlockingQueue;
public class GFG {
public void takeDemo() throws InterruptedException
{
// define capacity of BlockingQueue
int capacityOfQueue = 5;
// create object of BlockingQueue
BlockingQueue<Employee> BQ
= new LinkedBlockingQueue<Employee>(capacityOfQueue);
// Add element to BlockingQueue
Employee emp1 = new Employee("Ravi", "Tester", "39000");
Employee emp2 = new Employee("Sanjeet", "Manager", "98000");
// Add Employee Objects to BQ
BQ.add(emp1);
BQ.add(emp2);
// remove elements from the queue
// and follow this process again and again
// until the queue becomes empty
while (BQ.size() != 0) {
// Remove Employee item from BlockingQueue
// using take()
Employee removedEmp = BQ.take();
// print removedItem
System.out.println("Removed Item is :");
System.out.println("Employee Name - "
+ removedEmp.name);
System.out.println("Employee Position - "
+ removedEmp.position);
System.out.println("Employee Salary - "
+ removedEmp.salary);
// find size of BQ
int size = BQ.size();
// print remaining capacity value
System.out.println("\nSize of list :" + size + "\n");
}
}
// 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();
try {
gfg.takeDemo();
}
catch (Exception e) {
e.printStackTrace();
}
}
}
Output:
Removed Item is :
Employee Name - Ravi
Employee Position - Tester
Employee Salary - 39000
Size of list :1
Removed Item is :
Employee Name - Sanjeet
Employee Position - Manager
Employee Salary - 98000
Size of list :0
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