How complete all pending messages in aggregator, when header is recieved - apache-camel

Question

I would like to create something like "left outer join" based on camel routes. In my project, i have two routes, which are consuming data from 2 database tables and sending it row by row to next step (joinData). Both tables have same primary key and I would like to join data from these 2 tables based on this primary key. My scenario is:
<route id="select1">
//some code
<to uri="direct:joinData"/>
</route>
<route id="select2">
//some code
<to uri="direct:joinData"/>
</route>
<route id="joinData">
<from uri="direct:joinData"/>
<aggregate strategyRef="joinStrategy" completionSize="2">
<correlationExpression>
<jsonpath>$.ID</jsonpath>
<to uri="direct:result/>
</aggregate>
</route>
Last message from both sources contains special header/property set to true when record was last selected. Is there some possibility, how to complete rest pending messages waiting in aggregator, which weren't joined, when this special header came, or better, both header came? Because, now only joined messages are sent to result route. I would like to finsh all pending messages, when loading from DB ends.
Thanks for yours ideas.

Answer 1

Just add a completionPredicate to tell Camel in which situation the aggregate has to be considered as complete (in your case, it is when your special header/property is set to true).
You can use Camel Simple language to express the predicate. Example:
<aggregate strategyRef="myStrategy" eagerCheckCompletion="true">
...
<completionPredicate>
<simple>${body} contains 'STOP'</simple>
</completionPredicate>