BlockingQueue接口的take()方法用于检索和删除此队列的头。如果队列为空,则它将等待直到元素可用。如果在线程上工作并在该过程中使用BlockingQueue,则此方法效率更高。因此,如果没有可用的元素,则最初调用take()的线程将进入睡眠状态,从而让其他线程执行所需的任何操作。
用法:
public E take() throws InterruptedException
返回值:此方法在此BlockingQueue的开头返回值。如果队列为空,则它将等待直到元素可用。
异常:此方法引发以下异常:
- InterruptedException–如果队列为空,则在等待元素变为可用时发生中断。
注意:BlockingQueue的take()方法已从Java中的Queue类继承。
以下示例程序旨在说明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);
}
}
输出:
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();
}
}
}
输出:
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
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