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13 The Business Process Modeling Notation 357
Prepare Prepare
Transportation Transportation
Quote Quote
[Less than Truck- [Single
Load (LTL)] Package (SP)]
Single Less than
Package Truck-Load
(SP) (LTL)
Arrange Arrange Arrange Pickup
Arrange Delivery Arrange Pickup Delivery Appointment Arrange
Pickup Appointment Appointment Appointment with Pickup
Appointment with Client with Warehouse with Client Warehouse Appointment
Fig. 13.8 AND-split decorator attached to an empty task

BPMN YAWL BPMN YAWL

Task Task
Data-based XOR-
gateway XOR decorator

Subprocess Subprocess

AND-gateway AND decorator
Multiple instances task Multiple instances task
‘

Event-based XOR- Condition
gateway
Task with XOR
Looped task
decorators
Plain start event Start condition Inclusive OR-gateway OR decorator

Timeout/
Receive
Terminate event Final condition
Intermediate Timer/ Timeout/Receive Task
Message Event
Fig. 13.9 Mapping of tasks, events, and gateways

Figure 13.9 provides an overview of the mapping between tasks, events, and gate-
ways in BPMN and their corresponding constructs in YAWL. Note that although
every BPMN control-flow construct shown in this figure can be mapped to a cor-
responding construct in YAWL, the reverse is not always true. Specifically, an
event-based exclusive gateway in BPMN can always be mapped into an explicit
condition in YAWL. But in the reverse direction, there are situations where an
explicit condition in YAWL cannot be mapped to an event-based exclusive gateway
in BPMN. The reason for this is that an event-based exclusive gateway in BPMN
must be followed by either an event or a task of type “receive.” It cannot be followed
immediately by a gateway nor by a task of another type. This restriction does not