6.2. Declaring facts as events

You can declare facts as events in your Java class or DRL rule file so that the decision engine handles the facts as events during complex event processing. You can declare the facts as interval-based events or point-in-time events. Interval-based events have a duration time and persist in the working memory of the decision engine until their duration time has lapsed. Point-in-time events have no duration and are essentially interval-based events with a duration of zero.

For example, the following snippet declares that the StockPoint fact type in a stock broker application must be handled as an event:

import some.package.StockPoint

declare StockPoint
  @role( event )
end

If StockPoint is a fact type declared in the DRL rule file instead of in a pre-existing class, you can declare the event in-line in your application code:

declare StockPoint
  @role( event )

  datetime : java.util.Date
  symbol : String
  price : double
end