Applications of UML - Fields applying UML

UML has been used in following areas

Dependency (UML) - Differences with UML link

A UML link is run-time relationship between instances of classifiers, while a dependency is a model-time relationship between definitions.

Applications of UML - Fields applying UML

UML can also be used to model nonsoftware systems, such as workflow in the legal systems, medical electronics and patient healthcare systems, and the design of hardware.

UML state machine - Basic UML state diagrams

UML preserves the general form of the traditional state diagrams. The UML state diagrams are directed graphs in which nodes denote states and connectors denote state transitions. For example, Figure 1 shows a UML state diagram corresponding to the computer keyboard state machine. In UML, states are represented as rounded rectangles labeled with state names. The transitions, represented as arrows, are labeled with the triggering events followed optionally by the list of executed actions. The initial transition originates from the solid circle and specifies the default state when the system first begins. Every state diagram should have such a transition, which should not be labeled, since it is not triggered by an event. The initial transition can have associated actions.

UML state machine - The limitations of UML state machines

Harel statecharts, which are the precursors of UML state machines, have been invented as "a visual formalism for complex systems", so from their inception, they have been inseparably associated with graphical representation in the form of state diagrams. However, it is important to understand that the concept of UML state machine transcends any particular notation, graphical or textual. The UML specification makes this distinction apparent by clearly separating state machine semantics from the notation.

UML state machine - UML extensions to the traditional FSM formalism

UML state machines address exactly this shortcoming of the conventional FSMs. They provide a number of features for eliminating the repetitions so that the complexity of a UML state machine no longer explodes but tends to faithfully represent the complexity of the reactive system it describes. Obviously, these features are very interesting to software developers, because only they make the whole state machine approach truly applicable to real-life problems.

UML state machine - The limitations of UML state machines

The UML notation and semantics are really geared toward computerized UML tools. A UML state machine, as represented in a tool, is not just the state diagram, but rather a mixture of graphical and textual representation that precisely captures both the state topology and the actions. The users of the tool can get several complementary views of the same state machine, both visual and textual, whereas the generated code is just one of the many available views.

UML state machine - The limitations of UML state machines

Nevertheless, most of the statecharts semantics are heavily biased toward graphical notation. For example, state diagrams poorly represent the sequence of processing, be it order of evaluation of guards or order of dispatching events to orthogonal regions. The UML specification sidesteps these problems by putting the burden on the designer not to rely on any particular sequencing. However, it is the case that when UML state machines are actually implemented, there is inevitably full control over order of execution, giving rise to criticism that the UML semantics may be unnecessarily restrictive. Similarly, statechart diagrams require a lot of plumbing gear (pseudostates, like joins, forks, junctions, choicepoints, etc.) to represent the flow of control graphically. In other words, these elements of the graphical notation do not add much value in representing flow of control as compared to plain structured code.

UML state machine - The limitations of UML state machines

However, the notation of UML statecharts is not purely visual. Any nontrivial state machine requires a large amount of textual information (e.g., the specification of actions and guards). The exact syntax of action and guard expressions isn’t defined in the UML specification, so many people use either structured English or, more formally, expressions in an implementation language such as C, C++, or Java. In practice, this means that UML statechart notation depends heavily on the specific programming language.


UML may refer to:

Applications of UML - Modeling applications of UML using various diagrams

The following lists of UML diagrams and functionality summaries enable understanding of UML applications in real-world examples.

UML tool

UML tool is used broadly here to include application programs which are not exclusively focused on UML, but which support some functions of the Unified Modeling Language, either as an add-on, as a component or as a part of their overall functionality.

UML Designer - UML2

UML Designer is a graphical modeling tool for UML2 based on the Eclipse UML2 plugin and as defined by OMG. It provides support for the main UML diagrams and for UML profiles.

Executable UML - Model testing and execution

Verification will involve such things as human review of the models, performed by experts in the relevant domain, and automated checking of the Executable UML semantics. i.e., checking that the Executable UML model complies with the Executable UML metamodel.

Node (UML)

A node in the Unified Modeling Language (UML) is a computational resource upon which UML artifacts may be deployed for execution.

Powertype (UML)

In UML 2.x, a powertype is a metaclass whose instances are subclasses of a given class. The stereotype has been removed and the powertype is now indicated by typing the generalization set.

UML Partners

UML Partners was a consortium of system integrators and vendors convened in 1996 to specify the Unified Modeling Language (UML). Initially the consortium was led by Grady Booch, Ivar Jacobson, and James Rumbaugh of Rational Software. The UML Partners' UML 1.0 specification draft was proposed to the Object Management Group (OMG) in January 1997. During the same month the UML Partners formed a Semantics Task Force, chaired by Cris Kobryn, to finalize the semantics of the specification and integrate it with other standardization efforts. The result of this work, UML 1.1, was submitted to the OMG in August 1997 and adopted by the OMG in November 1997.

UML tool - Kinds of Functionality

UML tools support the following kinds of functionality:

Stereotype (UML) - Become

While UML 2.1 uses the «become» stereotype within the specification, it does not define it.

Executable UML - Statechart Diagram

Classes have lifecycles which are modeled in Executable UML with a statechart diagram. The statechart diagram defines the states, transitions, events, and procedures that define a class' behaviour.