Activity diagrams are graphical representations of
workflow
A workflow consists of an orchestrated and repeatable pattern of activity, enabled by the systematic organization of resources into processes that transform materials, provide services, or process information. It can be depicted as a sequence o ...
s of stepwise activities and actions with support for choice, iteration and concurrency. In the
Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally m ...
, activity diagrams are intended to model both computational and organizational processes (i.e., workflows), as well as the data flows intersecting with the related activities. Although activity diagrams primarily show the overall flow of control, they can also include elements showing the flow of data between activities through one or more data stores.
Construction
Activity diagrams are constructed from a limited number of shapes, connected with arrows. The most important shape types:
* ''ellipses'' represent ''actions'';
* ''diamonds'' represent ''decisions'';
* ''bars'' represent the start (''split'') or end (''join'') of concurrent activities;
* a ''black circle'' represents the start (''initial node'') of the workflow;
* an ''encircled black circle'' represents the end (''final node'').
Arrows run from the start towards the end and represent the order in which activities happen.
Activity diagrams can be regarded as a form of a structured
flowchart
A flowchart is a type of diagram that represents a workflow or process. A flowchart can also be defined as a diagrammatic representation of an algorithm, a step-by-step approach to solving a task.
The flowchart shows the steps as boxes of ...
combined with a traditional data flow diagram. Typical flowchart techniques lack constructs for expressing concurrency. However, the join and split symbols in activity diagrams only resolve this for simple cases; the meaning of the model is not clear when they are arbitrarily combined with decisions or loops.
While in UML 1.x, activity diagrams were a specialized form of state diagrams, in UML 2.x, the activity diagrams were reformalized to be based on
Petri net-like semantics, increasing the scope of situations that can be modeled using activity diagrams. These changes cause many UML 1.x activity diagrams to be interpreted differently in UML 2.x.
UML activity diagrams in version 2.x can be used in various domains, e.g. in design of embedded systems. It is possible to verify such a specification using model checking technique.
[I. Grobelna, M. Grobelny, M. Adamski, "Model Checking of UML Activity Diagrams in Logic Controllers Design", Proceedings of the Ninth International Conference on Dependability and Complex Systems DepCoS-RELCOMEX, Advances in Intelligent Systems and Computing Volume 286, Springer International Publishing Switzerland, pp. 233-242, 2014]
See also
*
Specification and Description Language
*
Business Process Modeling Notation
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Control-flow graph
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Data flow diagram
A data-flow diagram is a way of representing a flow of data through a process or a system (usually an information system). The DFD also provides information about the outputs and inputs of each entity and the process itself. A data-flow diagram h ...
*
Drakon-chart
DRAKON is a free and open source algorithmic visual programming and modeling language developed within the Buran space project following ergonomic design principles. The language provides a uniform way to represent flowcharts of any comp ...
*
Event-driven process chain
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List of UML tools
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Pseudocode
In computer science, pseudocode is a plain language description of the steps in an algorithm or another system. Pseudocode often uses structural conventions of a normal programming language, but is intended for human reading rather than machine re ...
*
State diagram
*
Flowchart
A flowchart is a type of diagram that represents a workflow or process. A flowchart can also be defined as a diagrammatic representation of an algorithm, a step-by-step approach to solving a task.
The flowchart shows the steps as boxes of ...
References
External links
Articles on UML 2 Activities and Actions
{{DEFAULTSORT:Activity Diagram
Unified Modeling Language diagrams
Systems Modeling Language
Modeling languages
es:Diagrama de actividades