同步运行Quartz作业

Question

I have a situation that I don't know how should I handle it.

I have a job in quartz which should start another nested job and get some results of the nested job and process them.

As I know, quartz run its job asynchronously. So, the thread which start the nested job cannot wait until the result of nested job being passed.

What is the solution here?

Answer 1

First of all quartz has a thread pool for running its jobs. You can read about it here :

In addition keep in mind that quartz can run jobs even in distributed manner. It allows to be run in cluster of 'active-active' servers, in this case you can't do any assumption on which of servers the job can be triggered. So implementing a singleton as jbh has stated can be tricky (at least you have been warned now :) )

In general, I think quartz should do what its good for - to run jobs. I don't think that implementing any complicated logic on top of this is a good idea. From your question I understand that you're trying to run one job from another (say job A runs job B). This makes sense if you have different trigger(s) assigned to A and B (otherwise why should B implemented as a quartz job?). So maybe you can refactor your code of job B so that the logic executed in B will be implemented in some class which is not related to quartz(say class C)? In this case you could assign different triggers to jobs A and B but inside just execute the code in class C?

Example (your approach):

class A implements Job {
  public void execute(JobExecutionContext context) throws JobExecutionException {
      // do A's stuff
      // call Job B somehow (???)
  }
}


class B implements Job {
  public void execute(JobExecutionContext context) throws JobExecutionException {
      // do something
  }

}

My suggestion:

class C {
   doSomeLogic(...) {...}
}


class A implements Job {
         public void execute(JobExecutionContext context) throws   JobExecutionException {
        // do A's stuff
        C c = new C();
        c.execute();  
  }


class B implements Job {
         public void execute(JobExecutionContext context) throws JobExecutionException {            
        C c = new C();
        c.execute();  
  }

}

Hope this helps.

Answer 2

Few ways. You can make some Static/Singleton type class that holds some sort of semaphore/session variables. Have the master job loop while checking this semaphore (synchronized for thread safety). And then retrieve the data similarly.

You can also utilize JobDataMap in a similar fashion. JobDataMap example