A Pool represents a participant in a Processes. It is also called a “swimlane” and is a graphical container for partitioning a set of activities from other pools. The activities within separate Pools are considered self-contained Processes. When this is true, the Sequence Flow may not cross the boundary of a Pool. A Message Flow is the mechanism to show the communication between two participants, and is the connection used between Pools.
When you create a pool in ER/Studio BA, a lane is created at the same time. If Validation is turned when you create the project, the lane is not labeled.
A pool can be shown as a “White Box” with all the details of the activity in the pool exposed. A “Black Box” hides all of a pool’s activities. No Sequence Flow is associated with a black box, but a Message Flow can attach to its boundaries. The default display for a pool is as a white box.
Note: When all lanes are removed from a pool it becomes a black box pool. The pool header label remains, but the lane area is hidden.