How to aggregate all events which lead to occurence of a complex event?

Question

Hi there,
Is it possible to aggregate all the events which lead to occurence of a complex event in this complex event?
Let's say we have six simple events
id    amount    groupId
1     1         1
2     0         2
3     1         1
4     1         2
5     2         2
6     1         1The definition of the complex event is
select sum(amount), groupId from myStream[range 20 seconds slide 20 seconds] group by groupId having sum(amount) = 3Consider I have the following class for my complex event:
public class ComplexEvent {
    private int groupId;
    private int amount;
    private List<SimpleEvent> events;
    // getters and setters
}Is it possible to have two complex events:
ComplexEvent1 = {groupId=1, amount=3, events=[{id=1, amount=1, groupId=1}, {id=3, amount=1, groupId=1}, {id=6, amount=1, groupId=1}]}
ComplexEvent2 = {groupId=2, amount=3, events=[{id=2, amount=0, groupId=2}, {id=4, amount=1, groupId=2}, {id=5, amount=2, groupId=2}]}How can we achieve it?

Answer 1

Hi,
I have blogged an example solution to this type of use case since it is a common scenario in CEP applications:
http://blogs.oracle.com/CEP/2010/08/enriching_complex_events_with.html
There is not currently out-of-the-box support for paging events to disk storage. If you truly have more events than can fit into the Java heap, you could try persisting the events to the database or to a data grid, such as coherence, and then joining with the database or cache to create the complex event containing the causal events.
Another approach is to horizontally partitioned the stream of incoming events across multiple servers.
Regards,
Seth