Apache Camel: Getting the aggregator's response? - apache-camel

Question

We use a splitter to iterate through the files within a zipped file, and along, we use a custom aggregator as well that gives us a list of bodies - of both the files within that main zipped file. Now, after that split, I'd like to extract the headers set during the aggregation block- processing which happens on the aggregator's result. But, the aggregator's output seems to get lost, and I don't get anything back after the split block.
I'm sure I'm not getting the basics of this. Would appreciate it if someone could help here.
<route id="main-route">
<split streaming="true">
<ref>zipSplitter</ref>
<choice>
<when>
<method bean="fileHandler" method="isY" />
<to uri="direct:y" />
</when>
<otherwise>
<to uri="direct:x" />
</otherwise>
</choice>
<to uri="direct:aggregate" />
</split>
<!--Do something by extracting the headers set during the processing underneath in the aggregation block i.e. process-data -->
</route>
<route id="aggregate-data">
<from uri="direct:aggregate" />
<camel:aggregate strategyRef="aggregationStrategy" completionSize="2">
<camel:correlationExpression>
<constant>true</constant>
</camel:correlationExpression>
<to uri="direct:process-data"/>
</camel:aggregate>
</route>
Aggregator-
public Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
Object newBody = newExchange.getIn().getBody();
Map<String, Object> newHeaders = newExchange.getIn().getHeaders();
ArrayList<Object> list = null;
if (oldExchange == null) {
list = new ArrayList<Object>();
list.add(newBody);
newExchange.getIn().setBody(list);
return newExchange;
} else {
Map<String, Object> olderHeaders = oldExchange.getIn().getHeaders();
olderHeaders.putAll(newHeaders);
list = oldExchange.getIn().getBody(ArrayList.class);
list.add(newBody);
return oldExchange;
}
}

Answer 1

You have to keep the aggregate logic inside the split scope. There should be single aggregate instance doing aggregation for your split as below,
<route id="main-route">
<split streaming="true" strategyRef="aggregationStrategy">
<ref>zipSplitter</ref>
<choice>
<when>
<method bean="fileHandler" method="isY" />
<to uri="direct:y" />
</when>
<otherwise>
<to uri="direct:x" />
</otherwise>
</choice>
</split>
</route>
you have to specify your aggregation strategy in split tag as a attribute like above code. So that, exchange return by every iteration will be available in aggregation strategy bean to aggregate.
Hope it helps :)