Development of Rigorous Adaptive Information Systems
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Transcript of Development of Rigorous Adaptive Information Systems
Rigoros and Adaptive ... Information Systems 1
Development of Rigorous Adaptive Information
Systems
Dr. Nasreddine AoumeurFIN, ITI, DB group
Course Site: wwwiti.cs.uni-magdeburg.de/~aoumeur wwwiti.cs.uni-magdeburg.de/iti_db/lehre/oois/inde
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Information Systems: Working Information Systems: Working definitiondefinition
– reactive systems (i.e. in continuous interaction with their environment), with
– large amount of immutable and non-immutable data (i.e. fixed and changing) and, with
– processes and activities for exhibiting behaviors on these (state-less and –full) data.
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Conceptual Modelling of IS in general
State-less and -ful DATA
Processes and Rules
Structural aspects
Behavioural aspects
E /R or Object paradigm
Petri Nets
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Conceptual Modelling of IS in UMLState-less and stateful DATA- Use Cases
- Class Diagrams
- Object Diagrams -Object Constraint Language
Processes and Rules- Sequence Diagrams
- Collaboration Diagrams
- State Diagrams
- Activity Diagrams- Component / deployment diagrams (implementation)
Stru
ctural asp
ectsB
ehavio
ural asp
ects
Forall C in ….
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Information system
View-orientedsystem modelling
Airport Flight
Passenger
UML diagrams
partial views
Use case ArrivalIncludes Landing Description The plane is landing. Then the passengers deplane and the luggage is unloaded. If the passenger has luggage then the passenger claims its luggage.
Conceptual Modelling of IS in UML
. . . .
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The origins of UMLUML resulted from the merging of three very popular OOD methods ----The three-Amigos
Booch’s OOD
Rumbaugh’s OMT
This focused on the external actors interacting with the system and their functional requirements.. A CASE tool called Objectory is available.
Booch’s method developed originally in 1991 based on OO Diagrams rather complex and CASE tool support essential. Theemphasis here was on design and implementation.
Object modeling technique supported by OMTool. Very Straightforward approach with an excellent text book. Widely adopted in academia and industry alike. Focus very much on analysis rather than design and implementation.
UML : Overview and History
Jacobson’s Use-Case approach
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• A Conceptual Modeling– Used to describe a simplified (abstract)
view of reality – in order to facilitate the design and then
the implementation of object-oriented software systems
• Conceptual Language– UML is primarily a graphical language that
follows a precise syntax.• A UNIFIED
– As By the start of the 90’s there was a flood of modeling languages, each with its own strengths and weaknesses.
UML : Overview and History . . . What is UML
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• In 1994 the UML effort officially began as a collaborative effort between Booch and Rumbaugh. Jacobson was soon after included in the effort.
• The goal of UML:– A comprehensive modeling language (all
things to all people) that– Promotion of the communication between
all members of the development effort.
• Version : UML 1.0 …. UML 2.0 (2003)
UML : Overview and History . . When is UML
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• UML is a language– Conforms to specific rules.– Allows the creation of (structural, behavioural, and
functional) various models.– Does not tell which models need to be created.
• UML is a language for visualizing– UML is a graphical language.– Pictures facilitate communication (a picture is worth
a thousand words)• UML is a language for constructing and
understanding– UML supports both forward and reverse
engineering.• UML is a language for supporting analysis,
specification and design• UML is intended primarily for software-
intensive information systems
UML : Overview and History . . What is UML
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• Diagrams: – Structural aspects :
» Class and object diagrams » Component and deployment (implementation)» OCL (object constraints language) for invariants,
pre- and post-conditions.– Behavioural aspects :
» Use cases, » Statechart, » Activity diagrams» Sequence diagrams
• A set of standardised diagramatic notations for representing different aspects of a (information) system. Containing static structural views, dynamic behavioural views and functional views
UML : Overview and History . . What is UML
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The Unified Modelling Language
• A design method or process, neither is it a methodology. There is no provision for project management specification of deliverables or life cycle or provision for estimation
• Users, developers can uses - Whatever process and life cycle – RAD they want
- Focus on Prototyping / incremental development - Focus on waterfall or spiral - they wished and - Provide their own project management and QA framework.
UML : Overview and History . . UML is NOT
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Static, structure diagrams• Class and instance diagrams
- These depict the components (classes or instances) within the system,- Their attributes and methods and their relationships with each other- The class diagram in particular is the most important single diagram in the design- Plus OCL constraints on invariants pre- and post-conditions
on methods• Component and subsystem diagrams (implementation) - How classes are grouped to form large assemblies - reusable components, sub-systems or packages of classes.• Deployment diagrams (implementation) - How the software components are deployed across a set of hardware components.
UML : Overview and History . . Inside UML
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Interaction diagrams• Use-case diagrams - Show the interface between the system and the outside world - Identify the actors in the system and their required functionality.• Sequence diagrams - Capture the functionality of the system suing the messages passing between objects. - Each sequence diagram shows the implementation of one scenario• Collaboration diagrams - Based on the instance diagram, it shows how specific scenarios are implemented by message sequence. - Similar to sequence diagrams but with more detail
UML : Overview and History . . Inside UML
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Dynamic behaviour of the system• Activity diagrams - Similar to Petri-nets, - Provide a view of the way objects interact and changes their states in consequence - The emphasis here is on system functionality as perceived by users• Statecharts - Harel Statecharts are developed from finite state notation - Illustrate the dynamic behaviour of objects. i.e. the way in which an object evolves through time - in response to external events.
UML : Overview and History . . Inside UML
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Most diagram types are involved, but principally at the conceptual level :
1. Conceive a use-case diagram - identify actors
- identify major functional requirements2. Conceive an initial Class diagram
- discover principle classes - represent important relationships
3. Event sequence diagrams - Examine possible object interactions - Determine class protocols At Implementation model different refinements are to undertake - combining or splitting classes, - adding or removing relationships, -defining the implementation of relationships, - introducing generalisations, interfaces - Introduce Component, sub-system and deployment models.
UML : Overview and History . . UML for IS
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A use case ... – Specifies what system will be used for, before the
defining what system is supposed to do– Describe functionality of a system yielding observable
results– Details scenarios that describe the interaction/dialog
between users of the system and the system itself. Identify who (or what) interacts with the system
– Does not indicate how the specified behavior is implemented, only what the abstract behavior is.
– Performs a service for some users of the system.» A user of the system is known as an actor.» An actor can be a person or another system.
– During the conceptual phase » Facilitates communication between the users and
developers of the system.» Facilitates the goal-based understanding of the
system
UML : Use Cases Overview and illustrations
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UML : Use Cases Basic artifacts
An Actor is consistent set of roles that user plays when interacting with the system (e.g. a user or outsider of the system that interacts with the system)
Actor Relationship UseCaseName
A link between the actors and the functions (use-cases). Different relationships are possible.
A Use Cases a sequence of actions performed by a system that yields a valuable result for a particular actor
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UML : Use Cases basic artifacts
System defines the boundary between the system and the actors interacting with the system and other systems
System
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• Model with use cases essencial parts of system functionality
• Model only those actors who involved in Use Cases
• Factor out common functionality using inheritance relationship <<include>>, <<extend>> stereotypes
• Describe only those events which are visible for the actor
• Each use case should describes a significant piece of system usage understandable by domain experts
• Use nouns and verbs accurately to help deriving objects and messages for interaction diagrams afterwards
UML : Use Cases---Modelling guidelines
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Specifies the participation of an actor in a Use Case
ActorUse Case
Association
Generalization
A taxonomic relationship between a less and a more general Use Case
UML : Use Cases basic artifacts
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<<extend>>
Extend a relationship
Specifies how the behaviour of the extension use cases e can be inserted into the behaviour of the base use case b
<<include>>
specialize a relationship
Specifies how the behaviour of the included p contributes to the behaviour of the base use case b
e b
pb
UML : Use Cases basic artifacts
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Student
Deposit funds
Prepare for examination
Louis acts as a student
Enroll for a course
Elen acts as a student
UML : Use Cases actors illustrations
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Student
Deposit funds
Prepare for Examination
Louis acts as a student
Enroll for a Course
Louis acts as a customer
customer
UML : Use Cases actors illustrations
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• Use case Arrival• Includes Landing• Actors plane, passenger• Preconditions non• Description The plane is landing.
Then the passengers deplane and the luggage is unloaded. If the passenger has luggage then the passenger claims its luggage.
UML : Use Cases --- AIRPORT illustration
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ArrivalPassenger
Departure TakingOff
Landing Plane
<<include>>
Airport
Flight
use caseuse case
actoractor
<<include>>
UML : Use Cases --- AIRPORT illustration
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Bank Consortium
Deposit
Withdraw Cash
Automated Teller Machine (ATM)
Transfer Funds
Maintain ATM MaintenanceCrew
Customer
UML : Use Cases --- ATM use illustration
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Use Cases Scenarien
• Ask the following questions:– What are the primary tasks that the system is
supposed to perform?– What data will the actor manipulate (add, store,
change or remove) in the system?– Which external changes does the system need
to know about?– Which changes or events will the actor of the
system need to be informed about?
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UML
Structural Modelling
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Use Cases : Introduction
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• A use case ... – Represents a functional requirement of the system
as a whole.– Is graphically represented as an oval with the name
of its functionality written inside.» Functionality is always expressed as a verb or a
verb phrase.• An actor is most typically represented as a
stick figure of a person labeled with its role name.
• Individual use cases can exist in relationships with other use cases much in the same way as classes maintain relationships with other classes.
Use Cases : Introduction
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• Names are used to distinguish one use case from another.
• Actors …– May be drawn as a stick figure, stereotyped class or
a graphical image of your own design.– Are connected to use cases by associations.– May be involved in generalization relationships with
other actors.– Exist outside the system boundaries (the
environment).
Terms and Concepts
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The Unified Modelling Language
Use-case diagramsThese depict the Actors in the system and the required functionality.
Actors
External entities People interested in system Other systems interfacing with the systemMay or may not be represented by a software component.Represented by stick people or other graphic.
Functions
Primary functionality of system seen from a users perspective.Linked to the actors involved with/interested in the function.Represented by ovals.
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Terms and Concepts
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• Use cases and Flow of Events– A use case, by itself, does not describe the flow of
events needed to carry out the use case.– Flow of events can be described using informal text,
pseudocode, or activity diagrams.– Use a note to attach flow of events documentation to
a use case.
Terms and Concepts
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The Unified Modelling Language
Use-case for library system
Returnbook
Staffborrower
studentborrower
Checkmember status
Reservebook
Browsecatalogue
Borrowbook
browser
Counterstaff
manager
Registermember
Usagereport
Updatecatalogue
Return late book
<<uses>>
<<uses>>
<<extends>>
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Terms and Concepts
• Organizing Use Cases– Packages may be used to organize (group) use
cases.– Generalization between use cases is used to extend
the behavior of a parent use case.– An <<include>> relationship between use cases
means that the base use case explicitly incorporates the behavior of another use case at a location specified in the base.
» Sometimes the <<uses> stereotype is used instead of <<include>>.
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Use Case Relationships
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Use Case Relationships
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• Use case diagrams …– Show a set of actors, use cases, and their
relationships.– Facilitate communication between non-technical
customers and developers due to their simplistic nature.
– Show the functionality of the system from the prospective of each user of the system.
– Model the context of the system.– Model the requirements of the system.
Use case diagrams
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Use Case Diagram
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Generating Use case diagrams
• To model the requirements of a system …– Identify all actors (users of the system).– Identify the needs, from the system, of each
individual actor.– Make each need a use case.– Identify redundant behavior within your set of use
cases, and factor it into common base-class use cases ( generalization ) .
– Do the same for actors.– Show the relationships between actors and use
cases.
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Modeling System Context
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CMs Generation shift: “Entity To Object”
Processes, Operations and Rules
From E/R to “Object-Object
Entity Name
Attribute1 : Type1
Attribute2 : Type2....Attributei : Typei
Property1
.....
n-m
i-j AssocPART
IS-A
m Entit(ies)
n Entit(ies)
data
data
operation
sop
erations
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First generation of CMs : “Entity first”E/R Conceptual Model
Customer
Name : StringBirth-Date : DateAddress : AddressIncome : Money
Open-Date
Bank
1-20-N Own
(Running) Account
Number : NatBalance : MoneyLimit : MoneyHistory : List[Date,Money]
IS-A
Saving Account
Number : NatInterest : PercentBalance
Processes and RulesAccount USE : First open --- then deposit – then (withdraw-deposit)* - then Close-or-be-closed
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CMs generation shift : “From Entity to object”From E/R to Object Model : Banking Example
Customer
Name : StringBirth-Date : DateAddress : AddressIncome : Money Open-Date
Bank
1-20-N Own
(Running) Account
Number : NatBalance : MoneyLimit : MoneyHistory : List[Date,Money]
Processes,operations and RulesAccount USE: First open - then deposit –> then (withdraw-deposit)* --> then Close-or-be-closed
+op
en- closed
eposit
with
draw
+open (date, bank)-close(date)-Debit(Amount)-Credit(Amount)
Own(account) : Boolean Deposit (amount) Withdraw(Amount)
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CM Generation shift : “From Entity to Object”From E/R Model to Object : ATM example
CustomerName : String
Amount
Date
1-20-N
Withdraw
AutomaticTellerMachine
ATM-Reference : StringCash : HiddenBank : StringTransaction : List[Money]History :List[Card-Nb,Acnt-Nb,Money
Bank-Card
Number : NatAccount-Nb: NatCode : String
Processes, operations and RulesATM-use : First enter-card – then enter-code – then enter-transaction— get money
- Read-card()- Enter-Pin(Code)- Enter-Amount(Money)- Get-Money(Money)
-Create()- Delete()- Accepted()- Rejected()
En
ter-cardE
nter-cod
een
ter-amou
nt
Get-m
oney
-Withdraw (ac, amount)- deposit (ac, amount)
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CM Generation shift: “From Entity to Object”From E/R Model to Object : The Library Example
Student
Name : StringSubscription-NbSemester Date-Out
Date-Back
0-N0-3 Borrow
Book
Reference : StringName : StringAuthor : StringPublisher : String
Processes, operations and RulesFirst subscribe-- Get library-card – (Borrow – Return –or– Penality)*--(be)Unsubscribe(d)
- Add()- Suppress()- ToBorrow(Date)- ToReturn(Date)
- Subscribe2Library- Unsubscribe-GetCard- ReceivePenalty
Su
bscrib
eU
nsu
bscrib
eB
orrowR
eturn
Pen
ality
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In real world terms:• An object represents an individual entity or
thing.• A class represents a group of objects that
exhibit some common characteristics or behavior.
• Classes are resulted from classification.
OO phylosophy : The real-world consists in a society of interacting objects.
• Examples of classes in real world:– Students– Graduate students– Undergraduate students – MS students– Ph.D. students
Object-Oriented Paradigm : General Overview
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• An object has– state: defined by the set of fields or
attributes.– behavior: defined by the set of methods or
operation that can be applied to the object.– identity: determined at the creation time to
uniquely referencing the object.
• Class– A template for creating objects.– Objects of the same class exhibit the same
behavior. – But generally, they posses different states
(attribute values)
Object-Oriented Paradigm : Main concepts
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Like in real world:
Book
one can
• Id : IF-43342• Title : „Petri Nets“• Author : „W.Reisig“• State :{available, borrowed, use..}
Object
has
Attributs (state)
Methods(behaviour)
• borrowed• returned• edited• .....
Object-Oriented Paradigm : Main concepts Object and Class
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The class MyDate The object d is an instance
of class MyDate
MyDate d:MyDate fieldsday (or:,variables day = 31month state month = 1year attributes) year = 2000
set (d,m,y) set (d,m,y)incDays (nDays) methods incDays (nDays)getWeekDay ( ) getWeekDay ()
Object-Oriented Paradigm : Main concepts
object-class
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The class Accounts The object Ac-Nasr instance
Account Ac-Nasr : Account
Number balance (fields, variables Number =
3130888limit state Balance = 1200history attributes) Limit = 20 History =
[20.2.2.07,…]
methods
+ open- Close- debit(amount)- Credit(amount- Tranfer(ac1,ac2)
Object-Oriented Paradigm : Main concepts Object-Class
+ openClose debit(amount)Credit(amountTranfer(ac1,ac2)
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- Pin(Id)
debit(Id, Money)
- Balance(Bal) : Money
- Limit(Lm) : Money
- History(Hs) :List[M.D]
The Account Class
credit(Id, Money)
- Transaction(Tr)
- AcntNb(AcN)
- CardNb(AcN)
Insert_Code(InsC)(C)
- Store(Sr) : Money
- State(St) : State
The ATM Class
Insert-Card(InC)()
Choose_Trans(CTr)(M)
Object-Oriented Paradigm : Main concepts Encapsulation
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• In general all attributes should be private. • Use EXCLUSIVELY methods such as debit
and credit to access the internal state. • Only methods that are part of the
“interface” should be public. • Instance variables and methods are
visibile within that object and other instances of the class.
• With respect to other objects and classes scope can be modified– private : accessible only within the
concerned class– protected : could be changed at subclasses– public : could be manipulated
everywhere
Object-Oriented Paradigm : Main concepts Encapsulation Principles
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ENCAPSULATION
class MyDate { private int day, month, year; public void set (int d, int m, int y) {day=d, month= m, year= y … } public void incDays (int nDays) {. . .} public int getWeekDay ( ) { . . . }}
class OtherClass { void anyMethod { MyDate d = new MyDate ( ) ; d.set (09, 5, 2007) ; d.month = 3; // COMPILATION ERROR !!! }}
Object-Oriented Paradigm : Main concepts Encapsulation At-work
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//without encapsulation:
circle k = new circle();k.radius = – 88;// radius negative!
//with encapsulationcircle k = new circle();boolean b =
k.setRadius(– 88);// radius never negative!
class circle{double radius, middlepointX, middlepointY;boolean setRadius(double newRadius){
if(newRadius > 0){radius = newRadius;return true;}
else return false; }
}
Object-Oriented Paradigm : Main concepts Encapsulation At-work
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A mechanism to organize classes by commonalities.– subclasses, specialization– superclass, generalization
• Is-a relationExample:
– A graduate student is a student.– A Master student is a graduate student.– A Ph.D. student is a graduate student.– An undergraduate student is a student.
Object-Oriented Paradigm : Main concepts Inheritance Concept
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Student
GraduateStudent UndergraduateStudent
MasterStudent PhDStudent
Object-Oriented Paradigm : Main concepts Inheritance concept and illustration
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Object-Oriented Paradigm : Main concepts Inheritance concept and illustration Running Account
Number : NatBalance : MoneyLimit : MoneyHistory : List[Date,Money]
+open (date, bank)-close(date)-Debit(Amount)-Credit(Amount)
Saving Account
Interest : PercentBalanceSav : Money
+open (date, bank)-close(date)- IncreaseInterest(Percent)- Money(money,account)
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Object-Oriented Paradigm : Main concepts Inheritance concept and illustration (ordinary) book
NumberCode : NatTitle : StringStatus : {available, borrrowed.}NumberCopies : Natural
Toborrow (date)-ToReturn(Date)
ThesisFieldSupervisorMarkDate-defenseGetCoppy
Periodics
EtidorsPublisher
Online-Publications
URLDurationsubscription
+subscribe- unsubscribe
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Base
Derived
class Base { Base(){} Base(int i) {} protected void foo() {…}}
class Derived extends Base { protected void foo() {…} Derived(int i) { super(i);… super.foo(); }}
As opposed to C++, it is possible to inherit only from ONE class.Pros avoids many potential problems and bugs.Cons might cause code replication
Object-Oriented Paradigm : Main concepts Inheritance at work
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Overloading:• Two or more
methods/constructors with the same name but different numbers or different types of parameters:
void methodB(int i) void methodB(float f)
Overriding– Replacing the implementation of a methods
in the superclass with one of your own.– You can only override a method with the
same signature.
Please Avoid overloading !!!!
Object-Oriented Paradigm:Main constructions Overloading and Polymorphism concept
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Object-Oriented Paradigm:Main constructions Overloading and Polymorphism concept
Polymorphism:• Inheritance creates an “is a”
relation:• For example, if B inherits from A,
then we say that “B is kind of an A”.• A same method same defined in the
class hierarchy• How to dynamically choose the right
methods ?
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GuiComponent width:int height:int center:point setOptimalSize( ) moveTo(newX, newY)
Editbox Scrollbar
minValue text: String
maxValue getValue( ) append(String)
setOptimalSize( ) getText( )
Object-Oriented Paradigm:Main constructions Polymorphism concept
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A subclass inherits all members of its superclass:
Variabls Methods
A subclass can: Add more variables Add more methods Override methods of its superclass
Scrollbar sb = new Scrollbar ( ) ; Q : What are the variables of sb? What are the methods that sb can
execute?
Object-Oriented Paradigm:Main constructions Polymorphism at-work
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GuiComponent g ; if (scrollbarWasSelected) g = new Scrollbar ( ) ; else g = new EditBox ( ) ;
g.setOptimalSize ( ) ; / / dynamic binding
• A reference to a superclass can point to objects
of its subclasses.• The pointer g is a polymorphic pointer.
Object-Oriented Paradigm:Main constructions Polymorphic Dynamic binding
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GuiComponent [ ] ga = new GuiComponent [3] ; ga[0] = new Scrollbar ( ) ; ga[1] = new Scrollbar ( ) ; ga[2] = new EditBox ( ) ; for (int i=0 ; i<ga.length ; i++) { ga[i] . setOptimalSize ( ) ; //line 6}
Q: Which version of setOptimalSize is called in line 6?
Polymorphism allows us to work with an object
without knowing its exact type
Object-Oriented Paradigm:Main constructions Complex Polymorphic Dynamic binding
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CASTING
class GuiComponent { void setOptimalSize ( ) { . . . } } class Scrollbar extends GuiComponent { void setOptimalSize ( ) { . . . } int getMinValue ( ) {. . . }
} guiComponent g ; g = new Scrollbar ( ) ;
Suppose we know that g currently points to a Scrollbar, and we want to call: n = g.getMinValue ( ) ;This will cause a compilation error (why?) …. Casting
problem
Object-Oriented Paradigm:Main constructions Polymorphism at-work (casting problem)
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The solution is casting (actually down casting).
Casting = convert a variable from one type to another.
Down Casting = convert from a superclass to one of its subclasses.
sb = ( (Scrollbar) g).getMinValue ( ) ;
Or:Scrollbar sb = (Scrollbar) g ;sb.getMinValue ( ) ;
We “tell” the compiler that g currently points to a Scrollbar.
if g does not currently point to a Scrollbar, a ClassCastException is thrown.
Object-Oriented Paradigm:Main constructions Polymorphism at-work (casting problem)
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C D
C D
association
aggregationwhole parta stronger form of association
C DcompositionIf an object d of class D is related to an object c of class C, then d depends existencialy on c.a stronger form of aggregation
C D directed association
Object-Oriented Paradigm:Main constructions Association Types
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Association EndsC D Each object of class C is related
to 1 to 5 objects of class DEach object of class D is related to exactly one object of class C
1 1..5
C DEach object of class C is related to at least one object of class DEach object of class D is related to arbitrary many objects of class C
* 1..*
C D Associated objects of class D are ordered*
{ordered}
1..*
Object-Oriented Paradigm:Main constructions Association Types
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Line Point
roleused to navigate
0..1 2
lRole determine -pRole
association name
direction2 points determine a line
directed aggregation
Object-Oriented Paradigm:Main constructions Association Types
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Class Diagrams
C D
C D InheritanceClass C inherits from class D
dependency relationshipClass C depends on class D
Object-Oriented Paradigm:Main constructions Association Types
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Engine Brakes Wheel Searing Wheel
Car
1..1 1..4 41..1 4 1
Object-Oriented Paradigm:Main constructions Association Types : Aggregation