Mule :Inbound connector consuming only if a business requirement is met

Question

I am having this requirement in a mule service that it should consumes from an inbound connector(flow message source) only if a business condition holds true. I need to look into the database whether that condition holds and then only my inbound connector should start consuming.Each time it should check for that condition and consume only if condition is true. Suggest best way to achieve implementation in mule.

Answer 1

This is something difficult to say without looking into your flow what exactly you want to implement .. Generally if you want your inbound endpoint to consume and the flow to work , the best option is to put a message filter after the inbound endpoint which will check the condition and allow the message to pass to next processor..

Since here you want to check the condition from the Database, what you need is to put a DB component after the inbound endpoint which will fetch the value of the business condition from the DB and then you can put either the message filter or Choice router to pass the message payload to the next Mule component

Answer 2

This is tipically done using the message filter integration pattern.

This pattern is implemented in Mule as (and only as) Filters, other patterns that could do the trick, specially routers and detour, but the more consistent way of do it is with filters.

In the case of Mule, you have a number of filters however there is no sql query based filter out of the box. This said. You have a number of options:

• a Filter in java, that you could instantiate as a spring bean injected with the datasource and then use as a custom filter with ar ref.
• if this is meant to be reusable, implement as a DevKit module.
• as a workaround, implement a sub-flow that leverages the database conector to fetch the query result and to then filter or not at the end of the flow with an expression filter.

Answer 3

Although a message filter is theoretically correct, in practice this is often accomplished using the Database Connector with a SELECT query that determines which rows should be processed in its WHERE clause. You can place the query in a <poll></poll> element at the beginning of a flow to execute the query on a schedule, as illustrated in the second example here.