All your publish-subscribe-channel
should have apply-sequence="true"
. Of course, if you don't use custom correlation
and release
strategies.
With apply-sequence="true"
the Framework populates standard correlation
MessageHeaders
and they are stored in the Stack
: the nested aggregator gets deal with correlation
of its scope and pop them from stack to be ready for the outer aggregation.
And the nested aggregator
should send its result to the input channel of outer aggregator
.
For the last one it will look like just a result of a service.