I’ll use the concept of tokens and refer to the UML specification to show how they have misinterpreted the specification. It shows a fairly basic and well understood process – that of making a reservation and boarding some transport.
#Workflow and activity diagrams symbols how to#
The following activity diagram is produced in IBM’s introduction to UML Activity Diagrams article – Activity Diagrams: What They Are and How To Use Them. Graph theory will teach someone what nodes and edges are and will help them interpret the UML specification when it refers to its symbols as such. Logic needs to be understood so that a practitioner knows when a node is acting as an AND gate or an XOR gate. Even when undertaking analysis and approaching IT from a business orientation there needs to be a basic understanding of both graphy theory and logic. There is a reason that all undergraduate IT degrees teach discrete mathematics to their pupils. When a node completes execution, a token is removed from the node and tokens are offered to some or all of its output edge.Īctivity Diagrams as Applications of Graph Theory and Logic When a node begins execution, tokens are accepted from some or all of its input edges and a token is placed on the node. The way different nodes treat tokens are described in detail in the UML Superstructure specification, however this is often ignored by people teaching Activity Diagrams to someone unfamiliar with them.Ī node may begin execution when specified conditions on its input tokens are satisfied the conditions depend on the kind of node. Different nodes have different effects on the tokens. Tokens aren’t something you depict when drawing an activity diagram, but having an understanding of how they work is useful to make sure you use the right type of notation for the real world process you’re illustrating. For example BPMN uses a lot of the same concepts as activity diagrams but allows for a more diverse and sophisticated depiction of a process.Īctivity diagrams work by modelling the flow of control through an invisible object called a token. Even if a business analyst chooses another notation, a thorough understanding of Activity Diagrams is often a good prerequisite to understanding the nuances of the other notation.
Understanding the basics is necessary to model a business process or workflow.
UML Activity Diagrams are one of the core UML artefacts that a business analyst can use.
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