Accessing Spring Batch Job/Step details via the generic query provider - spring-batch

Question

I'm setting up a batch job that moves data between three databases. I am planning on using the out of the box spring batch classes to handle the query from the first database, but i want to include details of the current job/step in the extract. The example spring config might look like this
<bean id="jdbcPagingItemReader" class="org.springframework.batch.item.database.JdbcPagingItemReader"> <property name="dataSource" ref="dataSource"/>
<property name="pageSize" value="1000"/>
<property name="fetchSize" value="100"/>
<property name="queryProvider">
<bean class="org.springframework.batch.item.database.support.HsqlPagingQueryProvider">
<property name="selectClause" value="select id, bar"/>
<property name="fromClause" value="foo"/>
<property name="sortKeys">
Is there a way via groovy or SpEL to access the current JobExecution? I had found this thread on access-spring-batch-job-definition but is assumes custom code.

Answer 1

Your configuration is cut off at the sortKeys entry so I'm not 100% sure what you are attempting to accomplish. That being said, using step scope, you can inject the StepExecution which has a reference to the JobExecution. Getting the JobExecution would look something like this:
<bean id="jdbcPagingItemReader" class="org.springframework.batch.item.database.JdbcPagingItemReader">
…
<property id="jobExecution" value="#{stepExecution.jobExecution}"/>
</bean>

Answer 2

The write count exists on the step context (StepExecution.getWriteCount()) so first you need to promote it to the JobExecutionContext.
I suggest using a Step listener with #AfterStep annotation for this
#Component
public class PromoteWriteCountToJobContextListener implements StepListener {
#AfterStep
public ExitStatus afterStep(StepExecution stepExecution){
int writeCount = stepExecution.getWriteCount();
stepExecution.getJobExecution().getExecutionContext()
.put(stepExecution.getStepName()+".writeCount", writeCount);
return stepExecution.getExitStatus();
}
}
Every step that perform the inserts will be added with this listner
<batch:step id="readFromDB1WrietToDB2" next="readFroDB2WrietToDB3">
<batch:tasklet transaction-manager="transactionManager">
<batch:chunk reader="reader" writer="writter" />
</batch:tasklet>
<batch:listeners>
<batch:listener ref="promoteWriteCountToJobContextListener"/>
</batch:listeners>
</batch:step>
<batch:step id="readFromDB2WrietToDB3" next="summerizeWrites">
<batch:tasklet transaction-manager="transactionManager">
<batch:chunk reader="reader" writer="writter" />
</batch:tasklet>
<batch:listeners>
<batch:listener ref="promoteWriteCountToJobContextListener"/>
</batch:listeners>
</batch:step>
You can use log4j to write the results to log within the Step Listener, or you can use the saved values in a future step. You need to use SpEL expression to read it, to Use SpEL expression you need to set the Writter/Tasklet at scope="step"
<batch:step id="summerizeWrites">
<batch:tasklet id="summerizeCopyWritesTaskelt"">
<bean class="Tasklet" scope="step">
<property name="writeCountsList">
<list>
<value>#{jobExecutionContext['readFromDB1WrietToDB2.writeCount']}</value>
<value>#{jobExecutionContext['readFromDB2WrietToDB3.writeCount']}</value>
</list>
</property>
</bean>
</batch:tasklet>