This figure demonstrates the relationship of the data bus, data tokens, and reactions.

The figure shows a reaction that gets activated due to availability of its data tokens. When all the data tokens are available and match the reaction conditions (for example, constraint on the values of a data token) then the reaction fires. The firing of a reaction executes the Active EJB method and may generate one or more data tokens. These data tokens can be for the return values to the calling process or for more requests for one or more Active EJBs. These data tokens are pushed to the AC4J data bus, which then routes them to the proper process context. The registered reactions may get matched and fired, depending on their conditions.