UML for Designers

7/29/2019 UML for Designers

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Prepared by Jayashree Kar

July 2004, Wipro Technologies

UML Diagrams for Designers

A P R E S E N T A T I O N B Y

W I P R O T E C H N O L O G I E S

Prepared by:

Jayashree Kar

Architect,

Corporate Vertical

Wipro Technologies

Aug, 2004


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23 Jun 2004 Wipro Confidential 2

What is UML?

UML stands for Unified Modeling Language.

UML is a set of standard notations used for modeling object oriented systems.

UML has evolved through the work of Grady Booch, James Rumbaugh, Ivar Jacobson andRational Software Corporation.

UML helps to specify, visualize and document models representing systems.

UML is a industry standard for modeling application systems.

UML model is methodology independent; i.e. UML can be mapped for all the widespread

methodologies.

UML model can platform independent.

UML model be either Programming language specific or independent..

UML has been accepted by Object Management Group (OMG) as the standard for modeling

OO systems.

UML is the foundation ofOMGs model driven architecture (MDA).

be either hardware and software platform specific or hardware and software


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Why UML Modeling?

Modeling is a highly creative process through which a solution is created iterating through

the requirements.

Provides standardization of models across the industry.

Provides common language to Architects, developers and business users.

Human brain is more receptive to pictures than texts; hence models convey lot more than

pages of text.

Modeling is essential part of large projects and is useful for small and medium size projects.

UML provides support in each phase of OOAD software life cycle.

Provides support for taking a holistic view of the system through the various models

representing logical, implementation, deployment, process and use case views.

Supports model driven architecture (MDA).

Enhances speed of project by providing code generation from the model.

Reverse engineering features of the modeling tool helps in understanding the existing

systems.

Has support for platform specific (PSM) as well as platform independent models (PIM)


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UML: Various Views

Implementationview

Deployment

View

ProcessView

Logical view Use case view

Contains classes,

interfaces, etc.

Logical view is for product

designers

Contains components, APIs etc

Implementation view is for component designers

Contains node, network

connectivity etc.

Deployment view is for

system administrators

Contains system boundary, use cases, actors etc.

Use case view is for all the stakeholders of the system

Contains processes, activities etc.

Process view is for business

owners


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UML Diagrams - Overview

UML defines Nine types of standard diagrams. They are as follows:

Structural diagram

Class

Object

Component

Deployment

Behavioral diagram

Use case

Sequence

Collaboration

Activity

State-chart

In addition, the following are used for model management: Model Management diagram

Package

Subsystem

Model


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UML Diagrams

Structural Diagram

UML Diagram Description

Class This is the most important diagram in OO design. It represents the staticbehavior of the system.

Object These describe the static structure of a system at a particular time. This is used

for modeling the pilots projects. This is also used for validating the model.

Component These diagrams describe the organization of physical software components,

including source code, run-time (binary) code, and executables. This diagram

provides overview of various separable pieces.

Deployment These diagrams depict the physical resources in a system, including nodes,

components, and connections. This is used by the systems administrator who

install and/or maintain the systems. This is used to depict the disaster recovery

sites and alternate sites as well.


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UML Diagrams

Behavioral Diagram


Use case This is the most important model used for the Object oriented analysis. Thisdenotes functionality of system using actors and use cases.This is also used for

understanding the boundary of the system.

Interaction diagram

(Sequence)

This is used for modeling the dynamic behavior of the system. This is used to

describe interactions among classes in terms of an exchange of messages over

time.

Interaction diagram

(Collaboration)

Collaboration diagrams represent interactions between objects as a series of

sequenced messages. Collaboration diagrams can describe both the static

structure and the dynamic behavior of a system. Most of the tools can convertsequence diagram to collaboration and vice versa.

State machine These diagrams describes the dynamic behavior of a system in response to

external events. This diagram is created for the state machines implemented by

the system. This is also useful in modeling reactive objects whose states are

triggered by specific events.

Activity These diagrams illustrate the dynamic nature of a system by modeling the flow

of control from activity to activity. An activity represents an operation on some

class in the system that results in a change in the state of the system. Typically,activity diagrams are used to model workflow or business processes and

internal operation. Swim lanes in activity diagram are used to denote

segregation of processes conducted by various organizations.



UML Diagrams

Model Management Diagram


Package This is used to organize elements of a system into related groups to minimize

dependencies between packages.

Package diagram can be used with class diagrams to logically group the

classes.

They are also used to group the use cases.

Subsystem This helps to manage the system and the model.

Model Model properties help understand the model items properly.


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Class Diagram/ Package Diagram

Class diagram is the most important class for representing logic model of the system

Symbols/

Notation

Description

class A class is represented by symbol.

It denotes a particular type of Objects. It has attributes and

operations that define the Property of the class.

Package A package is represented by the symbol.

It denotes a logical Group of classes. Since the visibility of class, its attributes And

operations can be defined at package level, proper Package definition is important to reduce

dependencies.

Association Association is represented by a line with arrowhead. It denotes conceptual relationship

between two classes. A class may have some attributes due to its association with the other

class. The association can be attached to a class; called associationclass

Aggregation Aggregation is a special type of association where the one class forms the part and the

other forms the whole. In aggregation relationship, the parts are shared across wholes.

Cardinality/

Multiplicity

Multiplicity is used with associations to represent how the objects are related. Associations

can be mandatory, optional, many to many, one to many etc.

Insurance

C1 C2

House Window

House Window

1..n1..n




Class diagram is the most important class for representing logic model of the system

Symbols/

Notation

Description

Composition Composition is very similar to aggregation and associates part and whole classes buthere the whole class takes care of creating and destroying the part hence the part isnot shared.

Active classes Active class is a special type of class that owns an execution thread to initiate controlactivity. It executes itself concurrently till it is completed/ terminated by an external

force. Passive class has instances that can execute only when another class performssome operation on it. It is either implemented by a process or a thread.

Generalization/Specialization

If a class is specialized that means it is inherited from a generalized class. A corporatecustomer is a specialization of customer class where it inherits the properties(attributes and operations) and can have extra properties of its own. It can overridesome of the properties as well.

Dependency In this the dependent class changes when the class it is depending upon, changes.

Visibility The attributes and operations in a class can be private, public or protected. Dependingupon the type the property has visibility to the outside world.

EventBufferList

(from data)BufferConfiguration

(from data)

Engine

(from policy)

Car

(from policy)11




UML notations can be extended to be used in different situations

Symbols/

Notation

Description

stereotypes Stereotypes are used extensively in the class diagrams to denote various type ofobjects such as DB tables, XML elements, EJB components etc.

Interfaces These are consists of constants and method descriptions that a class or a set of classwould like to expose to the world.

Class

Interface


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Package

Presentation Layer

Application Layer

Domain Layer

link



Object diagram

Models the static behavior of the systemUsed for modeling pilot projects or validating the modelsSymbols/ Notation Description

object This is an instance of the class. Graphically it is represented the same way asthe class with instancename:classname.

Object attribute This is used to represent the attributes at the object instance level.

Object operation This is used to represent the operations at the object instance level.

Others The notations used for drawing class diagram is used in the object diagram aswell.



Use case diagram

Used for representing functional model of the system

Symbols/

Notation

Description

System scope This is represented by a rectangular hollow box. This is used to define the boundary of the

system.

Use case This is represented by an ellipse shape. This is used to represent a set of transactions that

provides some tangible value to the actors.

actor An actor is represented by a stick man. An actor interacts with the use case to get some

tangible value from the system.

Links Actors are linked with the use cases when either they contribute to the use case or get

some benefits from the use case. Use cases are linked with other use cases via includes

and extends relationship.

Includes If some functionality is common to multiple use cases then it can be separated as a use

case and denoted by stereotype.

Extends If there are two use cases in which one use case has a special type is functionality

extending the other use case then it is represented by using extension point and denoted

by stereotype.

Packages Packages are used to group the use cases. Package is represented as

Maintain System

end user

Insurance



Use case diagram

Customer Read Purchase Policy Salesman

Analyze Sales S tatisti cs

Can be any type of

customer

Insurance system

Insurance system

System scope

Package

Use case

ActorActor

Notes

Association



Use case diagram

Insurance system

Stereotypes

Salesman

Create Sales Data

Update Sales Data

Browse Holiday Special Catalog

Browse Catalog


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Sequence diagram

Used for dynamic modeling of the system

Symbols/ Notation Description

Class roles The class role is a view of the class that helps achieve a particularfunctionality.

Actor The notation and use of actor is same as that described in the usecase diagram. The actors start a sequence by acting upon thesystem.

Represented the same way as the actors of the use case diagram.

Message A message is ideally a method call between two classes.

Lifeline Lifeline denotes the life span of a method call. Unless the methodimplementation is asynchronous, all the calls block till the childcalls return. This diagram helps to see if any object is blockedunnecessarily during a call which can be avoided.

Loops These are self calls; when a object makes a call to itself to get someinformation.


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Sequence diagram

Lifeline

Class roleMessage

Loop

: OrderEntryClerkOrderEntryWindow Order OrderLine Item

start()prepare() prepare() checkLevel()

isReorderLevel()

reOrder()

if reorder level is

reached


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Collaboration Diagram

Used for dynamic modeling of the system


Objects The collaboration diagram uses an instance of a class and denotes itsbehavior.

Links The links demonstrate the method calls between the classes.

Message numbering The messages flowing between the classes are numbered so as to

demonstrate how the messages are sequenced.


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Collaboration Diagram

: OrderEntryClerk

OrderEntryWindow Oder

OrderLine

item

1: start2: prepare()

3: prepare()

4: checkLevel()

5: IsReorderLevel()

6: reOrder()

Object

Message

numbering


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State machine Diagram

Also called statechart diagram. Used for dynamic modeling.

This is used to demonstrate the transitions for the state machine such as invoices,

Purchase orders


State State is represented by rounded edged rectangle. This is used to demonstrate thestates at which the state machine waits for events to take place to move to adifferent or same state.

A state may be a combination of states.

Event transition Represented by a line with arrow. An event that triggers a state machine to movefrom one state to the other.

Initial state Represented by a solid filled circle. Used for displaying the starting point of astate machine.

Final state Represented by a circle surrounding a solid filled circle. This marks the end of thestate transition of the state machine. Here either the transaction is committed or

rolled back.

Self Transition that keeps the state machine where it was before the event transition.

Created

Created

Created


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State machine Diagram

Invoice Created

Unpaid PaidPaidTransaction Committed

Start State

End State

State transition

States


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Activity Diagram

Used for modeling business requirementsSymbols/

Notation

Description

Activity This is represented by a rectangle whose vertical sides are represented as semi-circles.

This is used to represent activity as the name suggests.

Action flow Represented by lines with arrowheads. These are used to show how the actionschange the system behavior.

Initial state Notation and usage are same as that of the Statechart diagram.

End state Notation and usage are same as that of the Statechart diagram.

Swim lanes Swim lanes are represented by vertical bars with titles that divide the activitydiagrams into various sections. These are used to denote the processes used byvarious groups in an organization

Synchronization This is represented by a horizontal or vertical bar. This is used to denote concurrentactivities.

Decision Represented by a diamond and denotes a decision point.

States Notation and usage are same as that of the Statechart diagram. Denoted the sameway as the states in the state chart diagram.

Receive order

Procurement div


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Activity Diagram

Receive Order

Start

Fill Orders Send Invoice

Overnight

Delivery

Regular Delivery

Close orders

Receive

Payment

Send Invoice

End

Fork

Join

Branch

Join

Activity


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Component Diagram

Used for representing the implementation view of the system. Represents software

view of the system


Component Components are represented by the symbols described as

It is used to denote independent piece of executable or code that can be used toachieve some functionality.

Dependency This is denoted by a dotted line with arrowhead. The dependency can have a

name associated with it. This is used to denote type of dependency between twocomponents.

C1


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Component Diagram

Logging

component

Violation CorrelatorComponent

Monitoring

Component

Uses

Uses

Dependency

Component


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Deployment Diagram

Used for deployment view of the system. Represents hardware as well as software

view of the system. This view is used by the system administrators and maintenance

persons


Node This is denoted by a three dimensional box.

This denotes a physical hardware. The location and software installed

on this can be denoted to make it more meaningful for the system

administrators and maintenance people.

Communication This is denoted by a text between >. This is used to denote

the type of communication between the nodes.


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Deployment Diagram

Client PC

Web Server ApplicationServer

Client PC

DatabaseServer


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UMLDos and Donts

Dos:

Create models for the complex components in the beginning and attack the other

components later.

Keep the model modular to make them simple and clear; complex models are noteffective.

Check the accuracy of the model by using the tool or by expert review.

Maintain the model consistency and integrity- different views of the same model should

not tell a different story.

Iterate through the model so that it evolves over a period of time to provide the right

level of contents

Keep the model updated- can reverse engineer the code to update the model at the

end of the project.

Donts:

Dont mix UML with the project methodology; UML is generic enough to fit to any

methodology.

Dont try to create all the UML diagrams because they are defined; choose the onesthat are best fit for the solution to be designed.

Choose the right model depending on the audience; use case and activity diagrams

are perfect for the business users whereas class diagram, collaboration diagram and

sequence diagrams etc. are more useful for the designers.


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UML Tools

Some of the advanced tools available in the market are:

Rose (from IBM-Rational)

Together Control Center (From Borland)

Select Enterprise (From Aonix)

Magic Draw (Magicdraw)

OptimalJ (Compuware)

Microsoft Visio (Microsoft)

Some of the major features supported by the tools vendor that makes the tool lucrative for

usage are

Repository based modeling

Capability for code generation

Multi-user support

Reverse engineering (generating design model from the existing code)

Interchange of tools (via data exchange through XMI xml metadata interchange)

Integration with other tools (such as requirement management and testing tools)


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Whats Next

To start using UML in a project you may do the following:

Learn and practice UML

Choose a tool

Decide what diagrams are best suited for the project

Decide whether to use a platform specific model (PSM) or platform independent model

(PIM)

Stat using it and get the models reviewed by the experts

Some of the link that would help towards learning UML model is to

http://www.omg.org/gettingstarted/what_is_uml.htm

For definition of terms

http://www.softdocwiz.com/UML.htm
http://www.omg.org/gettingstarted/what_is_uml.htmhttp://www.softdocwiz.com/UML.htmhttp://www.softdocwiz.com/UML.htmhttp://www.omg.org/gettingstarted/what_is_uml.htm


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References

UML distilled

by Martin Fowler & Kendall Scott

UML 2 toolkit

by Hans-Erik Eriksson, Magnus Penkar, Brian Lyon, David Fado

Tool: Rational rose for illustrations

http://www.omg.org/gettingstarted/what_is_uml.htm#12DiagramTypes


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