Technology

Unified Modelling Language (UML)

The UML brings together a rich collection of modelling syntax, and provides a flexible semantic framework (i.e. grammar) in which the syntax can be used to model any (it is claimed) Object-Oriented software analysis, specification, design or implementation, devised by any methodology. By default this claim extends to all structured and unstructured projects as well.

The syntax of the UML is a collection of formally defined graphical motifs that are representative of software (or hardware) components, the relationships between those components, and supportive annotation motifs.

The motifs that represent components include representations for external and internal components, including human entities. It is these motifs that make up the syntax of the UML. In isolation these syntax components have no semantic context. The semantic context is established by connective motifs used to represent the relationships between the components. The combination of the component and relational motifs implies the grammar of the UML.

The UML grammar is further embellished by motifs containing textural annotation (i.e. comments) that clarifies the meaning and purpose of components and relationships. The finished form of a document written in UML may, in traditional terms, be called a diagram, or a set of diagrams. However, that terminology belies the complexity and sophistication that can be represented in the UML form.

Although the UML syntax can be written by hand, the form of the motifs can get quite sophisticated, and therefore difficult to depict - particularly by writers with poor drawing skills. Consequently it is more usual to use a computer application designed to correctly render the UML motifs - much the same as a word processor is used to render and manipulate written text. There are a number of such support tools available. In most circumstances, provided the correct UML grammar has been employed, these support tools can translate the UML document into appropriate computer programming language source code skeletons.

Of course, as with any language, it is up to the writer to ensure that the correct grammar is employed. Just as it is possible to create unintelligible English, either spoken or written, it is possible (and very easy) to create a UML document that is totally unintelligible. In order to be able to use the UML intelligibly training and practice is required.