使用spring-boot @scheduled注释同时执行两个调度程序

Question

I have 2 schedulers, which executes at a fixedDelay of 5s.


I have 2 use-cases:

1. If If - condition BusinessLogic class is true, then I want to sleep both the schedulers for a time of 3 secs , which means both the schedulers should execute now after 8 secs [5 secs + 3 secs].
2. If code qualifies the else condition, then both the schedulers should continue to execute at fixed delay of 5 secs.

Code :
Scheduler class:

import java.util.Date;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class TestSchedulers {

    @Autowired
    private BusinessLogic businessLogic;

    @Scheduled(fixedDelay = 5000)
    public void scheduler1(){
        Date currentDate = new Date();
        System.out.println("Started Sceduler 1 at " + currentDate);
        String schedulerName = "Scheduler one";
        businessLogic.logic(schedulerName);
    }
    @Scheduled(fixedDelay = 5000)
    public void scheduler2(){
        Date currentDate= new Date();
        System.out.println("Started Sceduler 2 at " + currentDate);
        String schedulerName = "Scheduler two";
        businessLogic.logic(schedulerName);
    }
}

Business logic class:

import java.util.Random;

import org.springframework.stereotype.Service;

@Service
public class BusinessLogic {

    public void logic(String schedulerName) {
        if(randomGen() < 100){
            System.out.println("\nExecuting If condition for [" + schedulerName + "]");
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }else if(randomGen() > 100){
            System.out.println("\nExecuting Else condition for [" + schedulerName + "]");
        }
    }

    //Generate random numbers

    public int randomGen(){
        Random rand = new Random();
        int randomNum = rand.nextInt((120 - 90) + 1) + 90;
        return randomNum;
    }

}

The problem

• Both the schedulers are not starting at the same time.
• When the if part is executing, then only one schedulers sleep for extra 3 secs, but I want both theschedulers to do so.

Log for reference:

Started Sceduler 1 at Sun May 26 12:34:53 IST 2019

Executing If condition for [Scheduler one]
2019-05-26 12:34:53.266  INFO 9028 --- [           main] project.project.App                      : Started App in 1.605 seconds (JVM running for 2.356)
Started Sceduler 2 at Sun May 26 12:34:56 IST 2019

Executing If condition for [Scheduler two]
Started Sceduler 1 at Sun May 26 12:35:01 IST 2019

Executing Else condition for [Scheduler one]
Started Sceduler 2 at Sun May 26 12:35:04 IST 2019

Executing Else condition for [Scheduler two]
Started Sceduler 1 at Sun May 26 12:35:06 IST 2019

Executing If condition for [Scheduler one]
Started Sceduler 2 at Sun May 26 12:35:09 IST 2019

Executing Else condition for [Scheduler two]
Started Sceduler 1 at Sun May 26 12:35:14 IST 2019

Executing If condition for [Scheduler one]
Started Sceduler 2 at Sun May 26 12:35:17 IST 2019

Executing If condition for [Scheduler two]
Started Sceduler 1 at Sun May 26 12:35:22 IST 2019

Executing Else condition for [Scheduler one]
Started Sceduler 2 at Sun May 26 12:35:25 IST 2019

Executing Else condition for [Scheduler two]
Started Sceduler 1 at Sun May 26 12:35:27 IST 2019

please help..

Answer 1

In each scheduler you invoke if(randomGen() < 100) independently of each other. So for one scheduler it could give result > 100 and for other < 100 or for both it could be the same. What you will need to do is to run randomGen() outside of the schedulers and store the single result in a way that both schedulers can access it and then they will rely on the same value in their if(randomGenValue < 100) statement and will behave the same way