empty YAWL tasks (i.e. YAWL tasks without decomposition) which serve purely for control routing. In the working example (Figure 1), the AND-split in the BPMN diagram is mapped to an empty task with an AND decorator. The BPMN2YAWL tool ensures that such empty tasks are only created when it is necessary, so as to minimise the number of empty tasks. Subprocess tasks in BPMN are mapped to composite tasks in YAWL. In the case where the subprocess in BPMN has an attached event (e.g. an error event), the mapping is more complicated. Figure 2 shows an exception in BPMN and the mapping onto YAWL. In the BPMN diagram, an error ‘invalid policy’ can occur within the ‘insurance check’ subprocess. This error is passed to the parent process, which then continues to ‘notify customer’. In YAWL a BPMN error is mapped onto a task that sets a subprocess variable (capturing whether or not the error has occurred) to ‘true’. The parent process reads this variable upon completion of the subprocess and proceeds according to the value of the variable. Check Policy Check Damage [complex or simple claim] [simple claim] Invalid Policy Process Insurance Claim Notify Customer [¬exception] [exception] Insurance Check Check Policy simple or complex claim Check Damage complex claim invalid policy invalid policy Notify Customer Process Insurance Claim (a) in BPMN (b) in YAWL OR gateway Intermediate error event End error event OR decorator Composite task Fig. 2. Mapping attached error events from BPMN to YAWL The transformation covers data and resource aspects in addition to control- flow. Properties and assignments in BPMN are mapped to variables, input/output parameters and input/output transformations in YAWL. Lanes in BPMN are mapped to roles in YAWL. Pools are treated as separate business processes (and each one is mapped separately), while message flows are not covered by the map- ping since their implementation depends on the communication infrastructure. The transformation does not cover transactions and compensation handlers because these constructs do not have a direct correspondence in YAWL. Also,
these constructs are underspecified in the current BPMN specification. Finally, the transformation does not cover complex gateways.
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- Fall '17
- FRANK K
- Management, Business process modeling, Business Process Modeling Notation, BPMN diagrams