UML tool

A UML tool is an application software that supports some or all parts of the Software_development_process or the creation of the artifacts described in the software industry standard Unified Modeling Language (UML), which is used in the field of Software engineering.

There are application programs which are not closely focused on UML alone, but which support to some degree aspects of the Unified Modeling Language, either as an add-on , as a component or as a part of their overall functionality.

=Aspects of Functionality=

Aspects of the functionality of UML tools include - among others - diagramming , code generation and reverse engineering .

==Diagramming==

Diagramming in this context means creating and editing UML diagrams; that is diagrams that follow the graphical notation of the Unified Modeling Language.

The diagramming part of the Unified Modeling Language seems to be a lesser debated part of the UML, compared to code generation.

The UML diagram notation evolved from elderly, previously competing notations. UML diagrams as a means to draw diagrams of - mostly - Object-oriented programming software is less debated among software developers. If developers draw diagrams of object oriented software, there is widespread consensus to use the UML notation for that task. On the other hand, it is debated, whether those diagrams are needed at all, on what stage(s) of the software development process they should be used and whether and how (if at all) they should be kept up-to date, facing continuously evolving program code.

==Code generation==

Code generation in this context means, that the user creates UML diagrams, which have some connoted model data, from which the UML tool derives (through a conversion process) parts or all of the source code for the software system that is to be developed. Often, the user can provide some skeleton of the program source code, in the form of a source code Template where predefined tokens are then replaced with program source code parts, emitted by the UML tool during the code generation process.

There is some debate among software developers about how useful code generation as such is. It certainly depends on the specific problem domain and how far code generation should be applied. There are well known areas where code generation is an established practice, not limited to the field of UML. On the other hand, the idea of completely leaving the code level and start programming on the UML diagram level is quite debated among developers, and at least, not in such widespread use compared to other software development tools like Compilers or Configuration management. An often cited criticism is that the UML diagrams just lack the detail which is needed to contain the same information as is covered with the program source. There are developers that even state that the Code is the design (articles [http://www.developerdotstar.com/mag/articles/reeves_design_main.html] by Jack W. Reeves [http://www.bleading-edge.com/]).

==Reverse engineering==

Reverse engineering in this context means, that the UML tool reads program source code as input and derives model data and corresponding graphical UML diagrams from it (as opposed to the somewhat broader meaning described in the article Reverse engineering ).

Reverse engineering encloses the problematic, that diagram data is normally not contained with the program source, such that the UML tool, at least in the initial step, has to create some random layout of the graphical symbols of the UML notation or use some automatic layout algorithm to place the symbols in a way that the user can understand the diagram. For example, the symbols should be placed at such locations on the drawing pane that they don t overlap. Usually, the user of such a functionality of an UML tool has to manually edit those automatically generated diagrams to attain some meaningfulness. It also often doesn t make sense to draw diagrams of the whole program source, as that represents just too much detail to be of interest at the level of the UML diagrams. There are also language features of some programming languages, like class- or function templates of the programming language C plus plus, which are notoriously hard to convert automatically to UML diagrams in their full complexity.

== Round trip engineering==

There are UML tools that use the attribute round trip (sometimes also denoted as round trip engineering ) to connote their ability to keep the source code , the model data and the corresponding UML diagrams in sync .

This means that the user should be able to change either the model data (together with the corresponding diagrams) or the program source code and then the UML tool updates the other part automatically.

=See also=

*List of UML tools *Unified Modeling Language