Java BlockingQueue take()用法及代碼示例

BlockingQueue接口的take()方法用於檢索和刪除此隊列的頭。如果隊列為空，則它將等待直到元素可用。如果在線程上工作並在該過程中使用BlockingQueue，則此方法效率更高。因此，如果沒有可用的元素，則最初調用take()的線程將進入睡眠狀態，從而讓其他線程執行所需的任何操作。

用法:

public E take() throws InterruptedException

返回值：此方法在此BlockingQueue的開頭返回值。如果隊列為空，則它將等待直到元素可用。

異常：此方法引發以下異常：

InterruptedException–如果隊列為空，則在等待元素變為可用時發生中斷。

注意：BlockingQueue的take()方法已從Java中的Queue類繼承。

以下示例程序旨在說明BlockingQueue接口的take()方法：

示例1:

// 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); 
    } 
}

輸出：

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]

示例2:

// 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(); 
        } 
    } 
}

輸出：

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

相關用法

注：本文由純淨天空篩選整理自gopaldave大神的英文原創作品 BlockingQueue take() method in Java with examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。