More Hello world issues - TaskletStep, StepExecutionListener

[PrebenNilsson]

Hello,

I have also tried my luck with the Hello World example, and made it run in its basic configuration. I then tried to expand it, so that I can save details about the jobExecution and the stepExecution in the executionContext.

I did it by implementing the StepExecutionListener interface in the Tasklet class. That gives me access to the stepExecution (without changing the configuration of the job ??!), but the Id (of the stepExecution) is null.

Can any of you guide me in the right direction ? My goal is to get access to the stepExecutionId and the jobExecutionId from the Tasklet class.

helloWorldJob.xml

<beans xmlns=...>  
                                   
  <import resource="helloWorldApplicationContext.xml"/>  

  <bean id="printtasklet" class="dk.bec.helloworld.PrintTasklet"/>  
         
  <bean id="hello" parent="printtasklet">
      <property name="message" value="Hello"/>  
  </bean>  
       
  <bean id="space" parent="printtasklet">
      <property name="message" value=" "/>  
  </bean>  
      
  <bean id="world" parent="printtasklet">
      <property name="message" value="World!"/>  
  </bean>  
  
  <bean id="taskletStep" abstract="true" class="org.springframework.batch.core.step.tasklet.TaskletStep">  
      <property name="jobRepository" ref="jobRepository"/>  
<!--  The below configuration line gives "No property 'listeners' found" -->
<!--  <property name="listeners" ref="printtasklet"/> -->
  </bean>  
       
  <bean id="simpleJob" class="org.springframework.batch.core.job.SimpleJob">  
      <property name="name" value="simpleJob" />  
      <property name="steps">  
          <list>  
              <bean parent="taskletStep">  
                  <property name="tasklet" ref="hello"/>  
              </bean>  
              <bean parent="taskletStep">  
                  <property name="tasklet" ref="space"/>  
              </bean>  
              <bean parent="taskletStep">  
                  <property name="tasklet" ref="world"/>  
              </bean>  
          </list>  
      </property>  
      <property name="jobRepository" ref="jobRepository"/>  
  </bean>  
</beans>

PrintTasklet:

package dk.bec.helloworld;

import org.springframework.batch.core.StepExecution;
import org.springframework.batch.core.StepExecutionListener;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.ExitStatus;

public class PrintTasklet implements Tasklet, StepExecutionListener{   
	  
	  private String message;
	  StepExecution stepExecution;
	  
	  public void setMessage(String message) {
	      this.message = message;
	  }   

	  public ExitStatus execute() throws Exception {   
	      System.out.print(message);   
	      stepExecution.getExecutionContext().putString("Message", message);
	      stepExecution.getExecutionContext().putDouble("Time", System.currentTimeMillis());
	      stepExecution.getExecutionContext().putLong("JobExecutionId", stepExecution.getJobExecutionId().longValue());

//		  The .getId() gives java.lang.NullPointerException:	      
//	      stepExecution.getExecutionContext().putLong("Id", stepExecution.getId().longValue());

	      return ExitStatus.FINISHED;   
	  }

	public ExitStatus afterStep(StepExecution stepExecution) {
		// TODO Auto-generated method stub
		return null;
	}

	public void beforeStep(StepExecution stepExecution) {
		this.stepExecution = stepExecution;
	}

	public ExitStatus onErrorInStep(StepExecution stepExecution, Throwable e) {
		// TODO Auto-generated method stub
		return null;
	}

}

[robert.kasanicky]

The id is null because StepExecution is not saved yet. Do you really need the value for some reason?

[PrebenNilsson]

Do you really need the value for some reason?

Well, maybe I don't need it. I was just pussled, that it was null.

And then I still can't figure out why the stepExecution works, just because I implemented the StepExecutionListener interface in the Tasklet class. I would have thought that it would take some change to the job configuration xml to make it work.

[robert.kasanicky]

And then I still can't figure out why the stepExecution works, just because I implemented the StepExecutionListener interface in the Tasklet class

TaskletStep checks whether the Tasklet implements StepExecutionListener, you only need to register nested listeners explicitly.

[PrebenNilsson]

Hi Robert,

OK. That makes sense. By the way - thank you for all your good work with this framework.

Best regards
Preben

[kdandu]

I need to save a list of keys into executioncontext so i can retrieve them during a next step.

Is there a way to do that while running the current taskletstep?

[lucasward]

Just implement StepExecutionListener so that you can get access to the ExecutionContext.

[hamtho]

Hi @all,

I am not that far to execute the first step. I recently used Hivemind as IOC (Unfortunately - but it was company policy in those days) and want to move to Spring now, so there might be some lacks concerning Spring as well.

I did everything as explained in the example, but somehow the PlatformTransactionManager is null, which results in the following stacktrace.
Can anyone tell me if - any how - I have to define the TransactionManager myself in this example.v

2008-11-07 11:51:39,012  INFO org.springframework.context.support.ClassPathXmlApplicationContext:412 - Refreshing org.springframework.context.support.
ClassPathXmlApplicationContext@cade31: display name [org.springframework.context.support.ClassPathXmlApplicationContext@cade31]; startup date [Fri Nov
 07 11:51:39 CET 2008]; root of context hierarchy
2008-11-07 11:51:39,079  INFO org.springframework.beans.factory.xml.XmlBeanDefinitionReader:323 - Loading XML bean definitions from class path resourc
e [simpleJob.xml]
2008-11-07 11:51:39,290  INFO org.springframework.beans.factory.xml.XmlBeanDefinitionReader:323 - Loading XML bean definitions from class path resourc
e [applicationContext.xml]
2008-11-07 11:51:39,348  INFO org.springframework.context.support.ClassPathXmlApplicationContext:427 - Bean factory for application context [org.sprin
gframework.context.support.ClassPathXmlApplicationContext@cade31]: org.springframework.beans.factory.support.DefaultListableBeanFactory@14ed577
2008-11-07 11:51:39,368  INFO org.springframework.beans.factory.support.DefaultListableBeanFactory:414 - Pre-instantiating singletons in org.springfra
mework.beans.factory.support.DefaultListableBeanFactory@14ed577: defining beans [jobLauncher,jobRepository,hello,space,world,taskletStep,simpleJob]; r
oot of factory hierarchy
2008-11-07 11:51:39,454  INFO org.springframework.batch.core.launch.support.SimpleJobLauncher:161 - No TaskExecutor has been set, defaulting to synchr
onous executor.
2008-11-07 11:51:39,537  INFO org.springframework.batch.core.launch.support.SimpleJobLauncher:114 - Job: [SimpleJob: [name=simpleJob]] launched with t
he following parameters: [{}]
2008-11-07 11:51:39,575 ERROR org.springframework.batch.core.step.AbstractStep:220 - Encountered an error executing the step: class java.lang.NullPoin
terException: null
java.lang.NullPointerException
        at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInStepContext(TaskletStep.java:247)
        at org.springframework.batch.core.scope.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:67)
        at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:352)
        at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:212)
        at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:143)
        at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:230)
        at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:198)
        at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:330)
        at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:78)
        at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:228)
        at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:115)
        at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:49)
        at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:110)
        at org.springframework.batch.core.launch.support.CommandLineJobRunner.start(CommandLineJobRunner.java:204)
        at org.springframework.batch.core.launch.support.CommandLineJobRunner.main(CommandLineJobRunner.java:251)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.codehaus.mojo.exec.ExecJavaMojo$1.run(ExecJavaMojo.java:271)
        at java.lang.Thread.run(Thread.java:619)
2008-11-07 11:51:39,599  INFO org.springframework.batch.core.launch.support.SimpleJobLauncher:116 - Job: [SimpleJob: [name=simpleJob]] completed with
the following parameters: [{}] and the following status: [FAILED]
2008-11-07 11:51:39,601  INFO org.springframework.context.support.ClassPathXmlApplicationContext:816 - Closing org.springframework.context.support.Cla
ssPathXmlApplicationContext@cade31: display name [org.springframework.context.support.ClassPathXmlApplicationContext@cade31]; startup date [Fri Nov 07
 11:51:39 CET 2008]; root of context hierarchy
2008-11-07 11:51:39,603  INFO org.springframework.beans.factory.support.DefaultListableBeanFactory:399 - Destroying singletons in org.springframework.
beans.factory.support.DefaultListableBeanFactory@14ed577: defining beans [jobLauncher,jobRepository,hello,space,world,taskletStep,simpleJob]; root of
factory hierarchy

Thanks for your help.

Thomas

[Dave Syer]

You need a transaction manager (just follow the examples). It looks like you probably aren't using the *StepFactoryBeans that the framework provides to make configuring steps easier. I would recommend you do that (as in the samples) so that you get an early warning about this kind of problem.

[hamtho]

Mmh.. as far as I can see no StepFactoryBeans are used in the example, but instead TaskletStep. At least not in Step1.
As far as I can read from the documentation, the PlatformTransactionManager has only be defined in the StepHandler but not when using Tasklets.
Is this true or is it only not mentioned especially in the documentation?

Thomas