Tasks | Scheer PAS Documentation

BPMN shape	BPMN description
	A Task is an atomic activity that is included within a process. A task is used in a BPMN diagram if the process can not be specified on a finer level of process model detail. Generally, an end-user and/or an application are used to perform the task when it is executed.

UML representation	UML description
	As already mentioned above, tasks are atomic from business point of view. However, from an execution point of view, this is not generally true. Actually, it is only true, if the task corresponds to a synchronous service call. In all other situations the task has to wait for a signal that the task has been done. Thus, the beginning of a task corresponds generally to a state waiting for a signal. At state entry, the task has to be triggered, i.e. by sending a notification. A task is mapped in a state with an entry handler and, depending on the task type, a signal with a signal handler. Signal and signal handler are indicated on the transition by (...)/(...).
	The handler of the state entry just calls an operation <task name>Begin. This operation logs the event of the beginning of this task. It is overridable so that own handling can be implemented.
	The signal handler calls an operation <task name>End when leaving the state. The task may deliver new data as result. These data are transmitted by the signal in the attribute 'message' of type Any. As before this operation logs the event of leaving this task. It is overridable so you can implement your own handling.
	The abstract <<PersistentState>> class contains the overridable operations that are invoked by each of the handlers.

Not for all tasks it may make sense to wait for an acknowledge signal. For instance, service tasks just call a service. The following table shows the general mapping:

BPMN	UML, generated state, handler and signal
Task Type	State Name	Stereotype	Entry Action	Signal
None	Waiting for <task name>	<<BPMNTask>>	send notification	<task name> Done
Service	Executed <task name>	<<BPMNServiceTask>>	call service	./.
Send	Sending <task name>	<<BPMNSendTask>>	send<task name>	./.
Receive	Waiting for <task name>	<<BPMNReceiveTask>>	./.	<task name> Received
User	Waiting for <task name>	<<BPMNUserTask>>	send notification	<task name> Done
Script	<task name>	<<BPMNTask>>	execute script	./.

Task type Manual is not supported as it makes no sense to use manual tasks in an executable process or pool.
Only unmarked tasks are supported yet. Marked tasks (as loop tasks, multiple instance tasks and compensation tasks) must be modeled explicitly.