Object-Oriented Software Engineering

CS288

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Lecture 1 - Object-Orientation & UML

Contents Overview Classifiers Dynamic Behaviour Static Modelling Summing Up

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Unified Modelling Language

First introduced in 1999 (about)First introduced in 1999 (about)

Still evolving, and extremely popular languageStill evolving, and extremely popular language

Current version 2.0 ratified August 2003Current version 2.0 ratified August 2003

We use UML 1.4, which is the current standard We use UML 1.4, which is the current standard

widely adopted in industrywidely adopted in industry

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Unified Modelling Language

Java allows us to closely tie the concepts from the UML model directly to the implementation.

• Easier to verify• Easier to modify• Easier to reuse

Think before you code.

UML allows us to build a conceptualmodel that we can examine andunderstand before we write a singleline of code.

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Unified Modelling Language

Visual modelling language Specify Visualise Construct Document

UML can be used to capture information about: Static structure Dynamic behaviour Environmental aspects Organisational aspects

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Overview

CreditCardCharges

ItemSeller

ManagerInterface

ItemDB

SalesServer

CustomerInterface

Client

ServiceInterface

SalesTerminal

1

*

1

*

Deployment ViewDeployment View

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Overview

height: Real age: Real

Person

Male_Person Female_Person

Static ViewStatic View

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Overview

public class Person {

public double height; public double age;

}

class Male_Person extends Person {// Now add stuff here to change // attributes and behaviour

}

class Female_Person extends Person {// Now add stuff here to change // attributes and behaviour

}

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Overview

LockedAvailable Sold

timed out

lock

unlock

buy

Behavioural View: Single ObjectBehavioural View: Single Object

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Overview

customer credit servicevendor

request item

show availability

select item

demand payment

insert card

charge card

Dynamic behaviour: communication patternsDynamic behaviour: communication patterns

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Classifiers

Classifier Function Notation

actor An outside user of the system

class A concept from the modelled system

component A physical piece of the system

data type A descriptor of a set of primitive values that lack identity

Name

node A computational resource

subsystem A package that is treated as a unit with a specification, implementation and identity

use case A specification of the behaviour of an entity in its interaction with outside agents

Name

<<subsystem>>

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Dynamic Behaviour: Use Cases

ATMCustomer

ValidatePIN

<<include>>

<<include>>

<<include>>

WithdrawCash

QueryAccount

OrderStatement

Operator

Add Cash

Startup

Shutdown

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Dynamic Behaviour: Sequence Chart

ATMCustomer

ATM Card ATM ControlCustomerInterface

BankServer

Card Inserted

Get Pin

PIN Prompt

PIN Input

Card Request

Card Data

PIN Entered

Validate PIN

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Dynamic Behaviour: State

A condition or situation during the life of an object during which it satisfies some condition, performs some action, or waits for some event. The Unified Modelling Reference Manual

I.E. State captures all the relevant information about an object at one specific moment with respect to the purpose of the object.

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Representation of a State

Activate Phone

entry/ register on network

exit / disconnect from network

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Events trigger Transitions

Closed Down Idlestartup

closedown

Top-level Statechart for ATM Control

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Full Label for a Transition

StateA StateBe1 [cond] / action1;action2

event name

guardcondition actions

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More ATM Control

Closed Down

Idle

Entry / displayWelcome

startup closedown

ProcessingCustomer

Input

card inserted / get pin

validation received [invalid card] / confiscate TerminatingTransaction

ProcessingTransaction

withdrawal selected [valid card] / display wait

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Phone Composite State Example

Off On

Power On

Power Off

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Phone Composite State Example

Off

On

Power On

Power Off

Idle

Active

unlock

incoming-call

end

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Phone Composite State Example

Off

On

Power On

Power Off

Idle

ActiveDialling

end

0-9

Connecting

Ringing

Talking

unlock

incoming-call

connect-key

connect-fail

call-accepted

connect-key

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Static Modelling: Class

Tuner class name

ChannelFrequency attributes

Get_FrequencySet_Frequency

operations

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Static Modelling: Inheritance Hierarchy

Tuner

A/V Tuner FM Tuner

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Static Modelling: Association

Tuner

Surf List1

1

Binary relation between classes

Can be implemented in different ways

1 Surf List to 1 Tuner

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Static Modelling: Aggregation

Surf List

Surf List Size

Add Surf ChannelDelete Surf ChannelSet Surf Channel

Source ID

Preset NumberPreset Name

Edit Preset NumberEdit Preset Name

0..*

• Specifies that an aggregate classis made up from components.

• Here: A Surf List has 0 or more Source ID

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Static Modelling: Aggregation

University

0..*

School

Department

Lecturer Students

1..*

1..*

1

1..*

1

1 1..*

Nested Aggregates

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Static Modelling: Putting it all together

A/V Source

Front End External Source

Surf List

Source ID

0..*

11

Tuner

1..*

is tuned to

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Summing Up

UML is a visual modelling language that covers a range of aspects of systems analysis and design

We have seen examples of modelling static structure and dynamic behaviour

Environmental and Organisational aspects can be covered too

______________ Use it!