Violet UML Tool

Overview Violet UML is an open source UML tool

enables the easy creation of simple UML diagrams.

Violet UML can function independently as a stand-alone application or as a plug-in for the Eclipse IDE Eclipse is a cross-platform, open source,

integrated development environment).

UML Diagram Types

UML diagrams can be assigned to two broad categories: structure diagrams and behavioural diagrams.

Structure diagrams are static consider the relationship between the structural

components of the system, without considering the system's behaviour over time.

6 structure diagrams: class, component, composite structure, deployment, object, and package.

Behavioural diagrams are dynamic and consider processes and how the system functions

over time. 7 classes of behavioural diagram: activity,

communication, interaction overview, sequence, state, timing, and use-case.

Violet UML supports the production of use-case, class, sequence, state, activity and object diagrams.

Drawing Diagrams With Violet UML

All UML diagrams are, in a general sense, made up of symbols.

Diagrams have symbols representing entities like classes, actors, use cases, etc and

symbols representing relationships between these entities like associations, messages, etc.

Conceptually, these correspond to the nodes and edges (links) within graph theory.

Placement of 'Node' Entities

Left click (select) the desired symbol on the Violet sidebar (e.g. the class symbol, when creating a class diagram).

Left click somewhere on the canvas to place a new symbol.

Right click on the symbol to edit its properties. Edit the fields to the desired values and click

OK.

Creation of 'Link' EntitiesTo join two symbols with some kind of link:• Select the desired link symbol on the sidebar

(e.g. the association symbol, when creating a class diagram).

• 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 link (shown as some form of line graphic).

• The properties box can again be brought up by right clicking on this line.

• Edit the fields to the desired values and click OK.

USE CASE

Use-case diagrams• To prepare a new blank canvas, create

a new use case diagramActor

• Select "Actor" on the Violet sidebar and place the symbol.

• In the Actor's properties, alter the name string to the desired value.

• 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 desired value.

Association Relationship

• Use the "Interaction" tool to link an actor to a use case.

• The actor and use case will now be linked by an association relationship symbol (a line).

Include Relationship

• Use the "<<include>>" tool to link one use case with another.

• The use cases will now be linked by an <<include>> relationship symbol.

• The include relationship's arrow symbol should point from one use case (A) to another (B) that represents some subset of the functionality of use case A.

Extend Relationship

• Use the "<<extend>>" tool to link one use case with another.

• The use cases will now be linked by a dotted line with an open arrow head. The text <<extend>> is present above the line.

• The extend relationship's arrow symbol should point from one use case (B) to another (A), where use case B represents an extension of the functionality of use case A.

Generalisation Relationship

• Use the "Generalization" tool to link one use case with another.

• The use cases will now be linked by an arrow with a triangular head.

• The generalisation relationship arrow should point from the more specific use case to the more general use case.

CLASS DIAGRAM

Class, Attribute, Operation

• Select "Class" on the Violet sidebar and place the symbol.

• In the Class's properties fill out the name, attributes and methods(operations).

• Class names consist of a lowercase noun or nouns.

• The first letter of each word should be capitalised.

• Attributes should also be nouns.

• Each attribute can have its visibility (public, protected or private) shown to the left of the attribute name .

• Public visibility is shown with a "+" symbol,• protected with "#" and • private with "-“

• An operation (or method) is a function or procedure performed by instances of that class.

• It is written lowercase and usually has a verb-noun structure.

• Operations are followed by a set of brackets containing any variables supplied when the operation is activated .

- empty if no variables are needed to call the operation.

• Operations can also be assigned public, protected or private

Association

• Use the "is associated with" tool to link two classes, creating a unidirectional association relationship

- whereby one class calls an operation in another class but not vice

versa.

• The association can be made bidirectional by removing the arrow via the association's property box.

• In the properties box, enter the multiplicity details in the "Start label" and "End label" fields.

Aggregation (a-part-of)

• Use the "Is an aggregate of" tool to create a link from one class to another.

• The include relationship's diamond symbol should be adjacent to class (A) linking to another (B) that represents some subset of the functionality of class A (indicating that B is a part of A).

Generalisation (a-kind-of)

• Use the "Inherits from" tool to link one class with another.

• The generalisation relationship arrow should point from the more specific use case to the more general use case.

SEQUENCE DIAGRAM

Object and Actor

• Select "Object lifeline" on the Violet sidebar and place the symbol.

• To designate an object as an actor enter <<actor>> as the first line in the object's name field.

Lifeline

• When an object is placed a lifeline is automatically created underneath.

• This line will grow as messages are added.Execution Occurrence (Focus of

Control)• Use the "Activation bar" tool to create an

execution occurrence on one of the lifelines.• Using the Select tool the execution occurrence

(focus of control) can be moved up and down the lifeline as required.

Message (Operation Call, Return)• To create an operation call use the "Call / Create

message" tool to - create a link from one execution occurrence bar to

another,- to a lifeline of another object (in which case an

execution occurrence is created automatically).• To create a return use the "Return message"

tool in an equivalent fashion.• As messages are added the lifelines and

execution occurrence boxes will extend automatically.

Object Destruction

• Object destructions, symbolised by a black X at the base of a lifeline, indicate the point where an object is no longer required and its existence ends.

STATE DIAGRAM

Initial State

• Select "Scenario start" on the Violet sidebar and place the initial state symbol.

• This symbol represents the state of the object when it first appears within the system.

State

• Select "State" on the Violet sidebar and place the symbol.

• The name entered in the properties box should convey the state of the object.

Transition and Event

• Use the "Event / Action" tool to link two states with a transition arrow.

.

• A transition occurs whenever the state/attributes of the object in question are modified in a way that is in some way significant, or relevant, to the functioning of the system.

• The properties of the transition can be edited to enter the name of the event leading to the transition

Guard Condition

• Where a state may transition to 2 or more possible future states then guard conditions are required.

• The event name of each transition leading from the single state to other states is written as a guard condition.

• Guard conditions set the transition to occur if the condition matches the specified criteria.