Drawing Sequence Flows on business process diagrams
You can draw a Sequence Flow to show the order that activities are performed in a process flow.
The drawing tools enforce the following BPMN rules for drawing sequence Flows:
▪You can draw a Sequence Flow between two processes within a pool or lane.
▪You can draw a Sequence Flow between a process in one lane and a process in another lane, only if the lanes are in the same pool.
▪You cannot draw a Sequence Flow between a process in one pool and a process in another pool. Only Message Flows are allowed between pools.
1 On the toolbar, click the Sequence Flow button.
2 On the diagram, click a process or event; then click another process or artifact.
The Sequence Flow is drawn between artifacts.
3 To adjust the arrangement of the line connections, click the Select Mode button, select the Sequence Flow, and then drag a connection point to a new location on the artifact.
4 To specify the event that initiates the Sequence Flow, complete the following steps:
▪Open the definition of the Sequence Flow line drawn from a process: select the Sequence Flow, and then click Edit > Edit “Sequence Flow Name”.
▪Click Choices; and then drag an event to the Initiating Event property field. An icon representing the event appears on the Sequence Flow line at the point of connection with the process.
5 You can specify that the Sequence Flow definition is part of a Category. A category is a simple grouping mechanism, introduced by the BPMN 1.0 specification. Assigning a Sequence Flow to a Category enables you to show a hierarchy of categories and the Sequence Flows that belong to them using a System Architect Decomposition diagram.
To specify a category, do one of these:
▪In the Category field, type a unique name for the category; then click Define.
▪Click Choices; then from the Select and Drag dialog box, drag a category name to the Category field.
6 To specify whether that the Sequence Flow is the default flow, click the Execution tab; then in the Default list, select True.
For Data-Based Exclusive Decisions and Inclusive Decisions, one type of flow is the Default condition flow. This flow will be used only if all the other outgoing conditional flow is not true at runtime.
7 You can specify conditions for the flow to occur.
Normal Flow: Normal Sequence Flow refers to the flow that originates from a Start Event and continues through activities via alternative and parallel paths until it ends at an End Event.
Conditional Flow: Sequence Flow can have condition expressions that are evaluated at runtime to determine whether or not the flow will be used. If the conditional flow is outgoing from an activity, then the Sequence Flow will have a mini-diamond at the beginning of the line.
Uncontrolled Flow: Uncontrolled flow refers to a Sequence Flow line that is not affected by any conditions or does not pass through a Gateway. A simple example of this is a single Sequence Flow connecting two activities. Another example of an uncontrolled flow is multiple Sequence Flows converging on an activity or multiple Sequence Flows leaving an activity. For each uncontrolled Sequence Flow, a token flows from the source object to the target object.
To model conditional flow, do this:
▪Click the Execution (Condition) tab.
▪If you specified a flow as the Default flow by setting the Default property in the Execution tab to True, then a slash at the beginning of a flow is displayed, and the Execution (Condition) tab will not appear upon reentry into the Sequence Flow line.
▪In Condition, type text that describes the condition. In the following diagram image, the text “After 4pm” has been placed in the Condition property of the line.
In the following diagram image, the text “After 4pm” has been placed in the Condition property of the line.
8 Exception Flow occurs outside the normal flow of the process and is based upon an Intermediate Event that occurs during the performance of the process. To model an exception flow between two processes, complete the following steps:
▪Click the Analysis tab; in the Initiating Event property, add an event.
▪The event that you add should have a Trigger Type of Exception.
A circle is added to the end of the Sequence Flow line adjacent to the “from” process.
▪To display the name of the initiating event, right-click the line and then click Display Mode. In the Display Mode dialog box, select to display Initiating Event.
The following image shows an exception flow in a diagram.
Next
You can draw the following types of forks, joins, branches, and decisions using BPMN:
▪Parallel Fork/Join (AND): To express a parallel fork or join, you use the gateway symbol with the AND stereotype specified. You can also express a parallel fork without using the AND gateway as described below under Parallel Forking.
▪Exclusive Decision/Merge (XOR): To express exclusive decisions and merges (otherwise known as XOR), you use either the gateway symbol without specifying a stereotype, or you use the gateway symbol with the XOR stereotype.
▪Inclusive Decision/Merge (OR): To express an OR gate, otherwise known as an inclusive decision or merge, you use the gateway symbol and specify the OR stereotype.
▪Complex Decision/Merge: You can model complex logic taken to decide the flow of a decision or merge gateway. To do so, you use the gateway symbol and specify a stereotype of Complex.
