Question

I have a Spring Batch job which takes parameters, and the parameters are usually the same every time the job is run. By default, Spring Batch doesn’t let you re-use the same parameters like that… so I created a simple incrementer and added it to my job like this:

http://numberformat.wordpress.com/2010/02/07/multiple-batch-runs-with-spring-batch/

When using the standard CommandLineJobRunner to run my job, I have to pass the -next parameter in order for my incrementer to be used.

However, when I run an end-to-end job test from within a JUnit class, using JobLauncherTestUtils.launchJob( JobParameters )… I can’t find a way to declare that my incrementer should be used. The job is just quietly skipped, presumably because it has already been run with those parameters (see note below).

The JobParameters class is meant to hold a collection of name-value pairs… but the -next parameter is different. It starts with a dash, and has no corresponding value. I tried various experiments, but trying to add something to the JobParameters collection doesn’t seem to be the ticket.

Does anyone know the JUnit equivalent to passing -next to CommandLineJobRunner?

NOTE: I presume that the the issue is my incrementer being ignored, because:

1. The job works the first time, and it works if I wipe out the job repository database. It only fails on retries.
2. The job works fine, retries and all, when I hardcode the variables and remove the parameters altogether.

Answer 1

JobLauncherTestUtils class contains a getUniqueJobParameters method which serves exactly the same need.

/**
* @return a new JobParameters object containing only a parameter for the
* current timestamp, to ensure that the job instance will be unique.
*/
public JobParameters getUniqueJobParameters() {Map<String, JobParameter> 
parameters = new HashMap<String, JobParameter>();
parameters.put("random", new JobParameter((long) (Math.random() * JOB_PARAMETER_MAXIMUM)));
return new JobParameters(parameters);
}

Sample usage would be,

JobParameters params = new JobParametersBuilder (jobLauncherTestUtils.getUniqueJobParameters()).toJobParameters();
     //extra parameters to be added
JobExecution jobExecution = jobLauncherTestUtils.launchJob(params);