How could I guarantee that only one JobInstance of a job run at the same time?

Question

Spring Batch documentation says: "Spring Batch will make no attempt to stop them from being run concurrently" (http://static.springsource.org/spring-batch/reference/html-single/index.html).

But I would like to get an error if I try to run a job and there is an instance of that job running. Is it possible?

I am using Spring Batch 2.1.8.

Answer 1

If you're aware that subsequent job will be queued up, you can use TaskExecutor.

1. Instantiate a task executor with maximum pool size, say 500

   <task:executor id="poolTaskExecutor" pool-size="500"/>
   

2. ThrottledTaskexecutor

   ThrottledTaskExecutor will pass only given number of tasks at a time to above poolTaskExecutor. This class can be found below in spring github, or you can download maven artifact. https://github.com/SpringSource/spring-batch-admin/blob/master/spring-batch-admin-manager/src/main/java/org/springframework/batch/admin/util/ThrottledTaskExecutor.java

3. Instantiate ThrottledTaskExecutor

   <bean id="throttledTaskExecutor" 
         class="org.springframework.batch.admin.util.ThrottledTaskExecutor">
     <property name="taskExecutor" ref="poolTaskExecutor" />
     <property name="throttleLimit" value="1"/>
   </bean>
   

4. ThrottledJobLauncher

   <bean id="throttledJobLauncher"
           class="org.springframework.batch.core.launch.support.SimpleJobLauncher">
       <property name="jobRepository" ref="jobRepository" />
       <property name="taskExecutor" ref="throttledTaskExecutor" />
   </bean>
   

All jobs launched using throttledJobLauncher above will be running only one instance at a time. This is more flexible that you can limit one or multiple jobs with given throttledLimit.

Actually above poolTaskExecutor definition and ThrottledTaskexecutor class is from spring-batch-admin. These are out-of-box feature. You just have to define ThrottledTaskExecutor with limit and include in the jobLauncher of your job.

Answer 2

You could check

jobExecution.getStatus()

as described in

https://stackoverflow.com/a/8711857/1627688