i cant understand this statement from oracle's AIA guide
"In a canonical integration, the EBF is an implementation of an EBS operation and calls other EBSs. An EBF will never directly call an ABCS or application. In other integration styles, the caller invoking the EBF can be an application or any other service"
Here is the full schema :
An EBF should not call an ABCS : The reason is that an EBS is in charge of routing the message to an ABCS.
If you need to route the message to a new ABCS, then you'll only have to redeploy or change the new EBS.
Hope that helps.