async steps

[DaniloR]

Hi all,

I have a simple (I hope :-)) question for the spring batch users.

I'm trying to understad if spring batch is the correct tool I have to use. What I need to do is the following:

1. Step A add a row in a db shared table
2. Step B read the row and start a specific step based on what the other step has written

As you can see the scenario is pretty simple; the complexity, at least for me, is to allow the step B to launch a new step/job in async way.
In this way, the step B can run some parallel substeps that execute a set of actions.

Do you think is it possible to achieve that? If yes, can you indicate me how?

Thanks,
Danilo

[dma_k]

In terms of Spring Batch to do the parallel steps is very easy:

<batch:job id="myJob">
	<!-- Below defined steps will be run in parallel: -->
	<batch:split id="jobSplit" task-executor="taskExecutor">
		<batch:flow>
			<batch:step id="stepA">
				<batch:tasklet>
					<batch:chunk reader="..." processor="..." writer="..." />
				</batch:tasklet>
			</batch:step>
		</batch:flow>
		<batch:flow>
			<batch:step id="stepB">
				<batch:tasklet>
					<batch:chunk reader="..." processor="..." writer="..." />
				</batch:tasklet>
			</batch:step>
		</batch:flow>
	</batch:split>
</batch:job>

But how will you implement stepB? Will you poll the database periodically? I would suggest to use Message Queue to communicate between stepA and stepB – that would be more efficient.