BPMN 2.0 basic concepts
Let's get into a bit more details on the main types of BPMN process elements.
BPMN 2.0 basic concepts
Events
Events are signals that something happens – this includes the start and end of a process as well as any interaction with the process’ environment.
There are 3 types of events:
- start events
- end events
- intermediate events
Start and End events
Start & End events
| Start Event Icon | End Event Icon |
|---|---|
 |  |
| event that triggers the process | event that defines the state that terminates the process |
Intermediate events
Message events
- represents incoming or outgoing messages from external parties - information, email, bank transfer
- Receive Message Event - incoming message occurring during the process flow, somewhere between start and end
- Send Message Event - outgoing message
| Send Message Event Icon | Receive Message Event Icon |
|---|---|
 |  |
| outgoing message | incoming message |
Activities
Task
- is an atomic activity within a process flow. You create a task when the activity cannot be broken down to a finer level of detail. A task can only belong to one lane.
| User task | Service task |
|---|---|
 |  |
| a task that requires the human to perform an action | a task that uses a Web service, an automated application, or other kinds of service in completing the task. |
Send Task
- represents a task that sends a Message to another lane or pool. The Task is completed once the Message has been sent.
Receive Task
- indicates that the process has to wait for a message to arrive in order to continue. The Task is completed once the message has received.
User Task
- is a Task that is performed without the aid of any business process execution engine or any application. It is performed when the user performs a certain action in the application.
Service Task
- is executed by a business process engine. The task defines a script that the engine can interpret. When the task begin, the engine will execute the script. The Task will be completed when the script is completed. It also provides a mechanism for a process to run a business rule on the process data.
BPMN Sub-Processes
In BPMN, a sub-process is a compound activity that represents a collection of other tasks and sub-processes. Generally, we create BPMN diagrams to communicate processes with others. To facilitate effective communications, we really do not want to make a business process diagram too complex. By using sub-processes, you can split a complex process into multiple levels, which allows you to focus on a particular area in a single process diagram.
Gateways
Gateways allow to control as well as merge and split the process flow.
Exclusive gateways
In business processes, you typically need to make choices — business decisions. The most common type of decision is choosing either/or. Exclusive Gateways limit the possible outcome of a decision to a single path, and circumstances choose which one to follow.
Parallel gateways
In many cases, you want to split up the flow within your business process. For example the sales and risk departments may examine a new mortgage application at the same time. This reduces the total cycle time for a case. To express parallel flow in BPMN, you use a parallel gateway.
| Exclusive gateway (XOR) | Parallel gateway (AND) |
|---|---|
 |  |
|
|
Closing gateway
- closes gateways by connecting branches with no logic involved
- symbol used depends on the initial gateway
- parallel gateways - waits for all input tokens and merges all into one single token
- inclusive gateways
- waits for all active inputs
- is informed about all preceding token flows - knows the path selected and are expecting the token from these