Architecting Modern Java EE Applications

Package access

Not all accesses from every package of the Entity Control Boundary pattern are allowed or make sense, respectively. In general, the logic flow starts at the boundary, going down to the control and entity package. The boundary package therefore, has dependencies to both the control, if existent, and the entity package. Using boundaries of other modules are not allowed and won't make sense, since the boundary represents a business use case. Accessing another boundary would mean to invoke something that should be a separate, standalone use case. Therefore boundaries can only go down the hierarchy to controls.

However, dependencies and invocations from boundaries to controls of other modules are allowed and do make sense in some ...