Migrating the Poll Component
In Mule 3, the
<poll> element was used to trigger a certain flow at a fixed frequency of time. This element was also a scope which required one (and only one) message processor to live inside of it. The output of that processor would be the message that the flow receives.
1 2 3 4 5 6 7 8 9 <flow name="poll> <poll frequency="1000"> <db:select config-ref="MySQL_Configuration"> <db:parameterized-query>SELECT * FROM PERSON></db:parameterized-query> <db:select> </poll> <flow-ref name="doProcess" /> </flow>
In Mule 4, the
<poll> element was replaced with the
<scheduler> element. Main differences are:
It just triggers the flow. It’s no longer a scope
It supports both fixed frequency and cron expressions
1 2 3 4 5 6 7 8 9 10 11 12 13 <flow name="poll> <scheduler> <scheduling-strategy> <fixed-frequency frequency="1000"/> </scheduling-strategy> </scheduler> <db:select config-ref="MySQL_Configuration"> <db:sql>SELECT * FROM PERSON></db:sql> <db:select> <flow-ref name="doProcess" /> </flow>
For more information on the
<scheduler> element, please read the Scheduler documentation.
<poll> element also supported a
<watermark> element which was used to aid and scheduled synchronizations. That element doesn’t exist anymore. Instead, please read the Migrating Watermarks page.