Author: Matthew Karlsen

Version: 0.9.1

License: This work is licensed under a Creative Commons Attribution 2.0 UK License.

Table of Contents

Violet is a UML editor with these benefits: Very easy to learn and use. Draws nice-looking diagrams. Completely free. Violet is intended for developers, students, teachers, and authors who need to produce simple UML diagrams quickly.
Violet is a UML editor with these benefits: Very easy to learn and use.

Violet (Very Intuitive Object Layout Editing Tool) is an easy-to-learn, open source UML editor. Violet is intended for students, teachers, and authors who need to produce simple UML diagrams quickly. It’s not intended as an industrial strength tool. Violet can be started as a single application, an applet, via Java Web Start, or as an Eclipse. BOUML is a free UML 2 tool box (under development) allowing you to specify and generate code in C, Java, Idl, Php and Python. BOUML runs under Unix/Linux/Solaris, MacOS X (Power PC and Intel) and Windows. From Wikipedia: The releases prior to version 4.23 are free software licensed under GPL. As the Violet project is composed of several sub-projects (plugins, products, etc.), it is organized as a main maven project (parent) with modules (children). Once everything is compiled and packaged, go to module directory/target to get the result of this packaging.

Drawing Diagrams with Violet UML

Overview

The purpose of this tutorial is to guide users in creating UML diagrams with the Violet UML plug-in for the Eclipse IDE. Eclipse is a cross-platform, open source, IDE (integrated development environment). Violet UML is an open source UML tool plug-in that extends the functionality of Eclipse to enable the easy creation of simple UML diagrams. Alternatively, Violet can also function independently of Eclipse in a stand-alone mode. Both Eclipse and Violet are installed in the AP labs. For home use, the tool is available for download on SourceForge (size ~2meg). To integrate Violet with Eclipse simply place it in your .../eclipse/plug-ins directory.

The range of available UML diagram types is outlined and the four UML diagram types covered within this tutorial are listed below. Following on from this, instructions on the general use of Eclipse and Violet UML are provided. Finally, the use of Violet to create each of the four emphasised diagram types (use-case, state, class and sequence) is detailed in four respective sections.

UML Diagram Types

UML diagrams can be assigned to two broad categories: structure diagrams and behavioural diagrams. Structural diagrams are static and consider the relationship between components within the system independent of considerations of time. Within the UML 2.0 specification there are 6 structural diagrams (class, component, composite structure, deployment, object, and package). Behavioural diagrams are dynamic and consider processes and how the system functions over time. The UML 2.0 has 7 classes of behavioural diagram (activity, communication, interaction overview, sequence, state, timing, and use-case). Interaction diagrams form a subset of these behavioural diagrams (consisting of communication, interaction overview, sequence, and timing diagrams). A taxonomy of UML diagrams is presented below. Further details concerning these diagrams can be found in Dennis, Wixom and Tegarden (2005 p29-35).

UML 2.0 diagrams
- Structural diagrams
  - Class
  - Component
  - Composite structure
  - Deployment
  - Object
  - Package
- Behavioural diagrams
  - Activity
  - State
  - Use-case
  - Interaction diagrams
    - Communication
    - Interaction overview
    - Sequence
    - Timing

Whilst UML 2.0 specifies fourteen diagrams in reality a number of these diagrams are more commonly used than others. Violet UML supports the production of use-case, class, sequence, state, activity and object diagrams. Of these six diagram types this tutorial covers use-case, class, sequence, and state diagrams.

Creation of a New Diagram

This section explains how to open Eclipse, create a new project, and prepare Violet for diagram editing.

To run Eclipse from within the UniS AP Labs navigate the start menu as follows: Start > All Programs > Departmental Software > Computing > eclipsec.
After Eclipse is executed you will be presented with a 'Workspace Launcher' window requesting you to choose the workspace that you wish to work with. Use the path 'H:workspace' (a /workspace folder in your home folder) or a different path within your home folder if you wish. This workspace folder is where Eclipse saves all of your projects and files that you create whilst working with it.
When you first load up Eclipse you will be presented with the welcome tab, giving you the options of 'Overview', 'What's New', 'Samples', 'Tutorials', and 'Workbench'. Select the 'Workbench' option on the right hand side or close the welcome tab to be taken to the main Workbench view.
In the top left, select File > New > Project. In the 'New Project' window click the arrow next to the General folder to view it's contents. Select 'Project' within the General folder and click next.
Enter 'COM1012' in the 'Project name:' field, or another string of your choice, and click finish. You will now notice that the COM1012 project folder has been added to the Package tab on the left hand side of the workbench.
To create your first diagram, right click on the COM1012 project and select New > Other (keyboard shortcut Ctrl-N). Within the 'New' window, click the arrow next to the 'Violet UML Editor' folder to view the range of available Violet diagrams. Select the diagram choice that you want (such as Use Case Diagram) and click Next. By default Eclipse has now chosen COM1012 as the parent folder - this is fine. Type a file name such as COM1012_UseCase_Question1 and click Finish.
The diagram created is now visible inside the COM1012 project folder, as indicated by it's indentation and placement below the COM1012 project within the package explorer tab. The Violet UML interface and and editing canvas should now be open in a new tab within the central pane of Eclipse.

Drawing Diagrams With Violet UML

General Instructions

All UML diagrams are, in a general sense, made up of symbols. Diagrams have symbols representing entities (classes, actors, use cases, etc) and symbols representing relationships between these objects (associations, messages, etc). Conceptually, these correspond to nodes and edges (connections) within graph theory. To avoid repeated duplication of instructions the general usage of Violet UML with respect to the placement of nodes and connections is explained in this section.

Placement of Nodes

Entities are placed in the following way:

Violet Uml Editor 3.0

Left click (select) the desired symbol on the Violet sidebar.
Left click somewhere on the canvas to place a new symbol.
Right click on the symbol to edit it's properties.
Edit the fields to the desired value and click OK.

Creation of Edges (Connections)

To join two symbols with some kind of connection:

Select the desired connection symbol on the sidebar.
With the tool selected place the mouse cursor over the symbol to link from.
Hold down the left mouse button, drag the cursor over the symbol to link to, and release.
The symbols are now linked by the desired connection (shown as some form of line).
The properties box can again be brought up by right clicking on this line.
Edit the fields to the desired value and click OK.

Use-case diagrams

To prepare a new blank canvas, create a new use case diagram, as described in the preceding section. The remainder of this section explains how to use each of the use case diagram 'tools' on the Violet sidebar (right hand side, main pane). Further information on use case diagrams is available within Dennis, Wixom and Tegarden (2005 p178-186).

Actor

Select 'Actor' on the Violet sidebar and place the symbol.
In the Actor's properties, alter the name string to the desired value.
Actor names should be common nouns (not proper nouns such as the names of individuals).
All first letters should be capitalised (e.g. Medical Doctor).

Use Case

Select 'Use case' on the Violet sidebar and place the symbol.
In the properties box of the use case, alter the name string to the desir