Mule Batch Job (Part 2)

MULE BATCH JOB

(PART 2)

The process records stage:

In this phase we have two steps; the first one is : get-user-account-step that gets a user account record, and the second one is: failures-step that processes failed records. As an example, if the the current user does not have an account, then NoUserAccountExistException exception is thrown, this exception is handled by sending the curent user with the exception message to a JMS queue for later check.

In case the first step returns an existing account information, the failures step is skipped as only failures are captured by using the config: accept-policy="ONLY_FAILURES". The returned account info may be used to generate a CSV file that is required by business operations.

The following depicts the batch step: get-user-account-step; here we hold the current user id in a record variable using the expression: #[recordVars['currentUser']] in the enricher:

<batch:step name="get-user-account-step">
   <logger message="Start processing step: get-user-account-step"
           level="INFO"/>
   <enricher source="#[payload['id']]" target="#[recordVars['currentUser']]">
      <set-payload value="#[payload]" doc:name="Set Payload"/>
   </enricher>
   <flow-ref name="get-account-record" doc:name="Flow Reference"/>
   <logger message="Account record payload: #[payload]" level="INFO" doc:name="Logger"/>
   <!-- We may transform the record payload here and push it into a CSV file -->
</batch:step>

The reference to the flow that gets the current user account called get-account-record is depicted in the following flow that shows the use of the record variable: currentUser to get the corresponding account.

In this flow we also use a component just after the query that returns the account info, this component checks if the returned account info is empty, then it throws the exception: NoUserAccountExistException.

<flow name="get-account-record" doc:name="get-account-record" processingStrategy="synchronous">
 <logger message="Start getting account record for user:
               #[recordVars['currentUser']]" level="INFO"/>
 <db:select config-ref="MySqlDatabase" doc:name="get user account account">
    <db:parameterized-query>
       <![CDATA[SELECT * FROM usermodel.Accounts WHERE user_id=#[recordVars['currentUser']];]]>
    </db:parameterized-query>
 </db:select>
 <component class="com.appnov.batch.AccountVerifier" doc:name="Java"/>
 <logger message="End getting account user: #[recordVars['currentUser']]" level="INFO"/>
</flow> 

The following depicts the batch step: failures-step; that obviously accepts only failed records:

<batch:step name="step-failures" accept-policy="ONLY_FAILURES">
   <logger message="Failed record with user id:  #[recordVars['currentUser']]" level="INFO"/>
   <set-payload value="#[getStepExceptions()]" doc:name="Set Payload"/>
   <foreach collection="#[payload.values()]" doc:name="For Each">
    <logger message="Current user: #[recordVars['currentUser']] record has been failed,Exception:
                      #[payload]" level="INFO"/>
     <!-- We may send the Payload here to a JMS queue or use it to create a report file-->
   </foreach>
</batch:step>