COEN244: Inheritance & Composition using Uniﬁed …COEN244: Inheritance & Composition using...

COEN244: Inheritance & Compositionusing Unified Modeling language (UML)

Aishy Amer

Electrical & Computer Engineering

OutlineModeling with UML

UML basic notation

Case study:video rental store

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Modeling problems with UML

When a OO program becomes sufficiently complex,

it becomes difficult to visualize

the relationships between classes to implement

A common approach is to use graphical notation

to describe the relationships among real-life entities whose

behavior the application should emulatecircles and cylinders,customers and accounts, inventory items and theirsuppliers

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OO analysis describes

the real-life system activities in the form of cooperating classes

OO design describes

the structural elements of the system:system architecture, subsystems, classes link

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Design and analysis are similar butdesign gives more details such as additional links or improveperformance

OOP:

making system components as independent as possible

but describe the cooperation appropriately and precise

Can you separate analysis, design and implementation in OOP?

To which extent?

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OOP: Analysis, design and implementation are stronglyrelatedWhat are the advantages?

OOP: no ad hoc object relationships

Hence we need a unified graphical tool (notation) thatan analysts, designer and programmer use

UML is a solution

Basic the idea :an object is a system component with its data,

functions, and relation to other objects

The result is object diagrams that are shared between

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UML basic notation

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Associations among classes

Association: connection between classes

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Aggregation, composition, inheritance

Aggregation: one object is part of another object oranother object contains the first object (has it)

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Multiplicity of relationships

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A case study: video rental store

For a rental store: a program should keep track of customersborrowing and returning movies

What are the objects?

Rental item data: title, quantity on hand, & ID

Customers data: name, phone, number of movies borrowedand their IDs

The movie data is stored in a file with a letter indicating themovie category (’f’ for feature, ’c’ for comedy, ’h’ for horror)

When data is read into memory, the information is storednumerically (1=’f’, 2=’c’ 3=’h’)

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when data is displayed it is displayed as words (’feature’,’comedy’, ’horror’)

when a customer returns a movie, the user enters his/herphone number to search the database

after verification: the quantity on hand is decremented andmovie id is added to the list of movie id borrowed by thiscustomer

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Analysis and design:UML notation for classes with their attributes and operations

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Analysis and design: class relationships

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Design and implementation:UML class diagram for the program (adds more details)

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A case study: main()

/ / L i s t i n g 14.16 Implementat ion o f f u n c t i o n main ( ) Store ( f i l e v ideo . cpp ) .#include <iostream >using namespace std ;#include " s to re . h " / / t h i s i s a necess i ty

i n t main ( ) {Inven to ry inv ; Store s to re ; / / de f ine ob jec tss to re . loadData ( inv ) ; / / load datawhile ( t rue ){ i n t r e s u l t = s to re . f indCustomer ( i nv ) ; / / check r e s u l t s

i f ( r e s u l t == 0) break ; / / te rmina te programi f ( r e s u l t == 2) / / 1 i f not founds to re . processItem ( inv ) ; } / / process the casset te

s to re . saveData ( inv ) ; / / save databasereturn 0;

}

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A case study: Comments

main() does not ask the user to enter data and does notoutput anything itself

Try to find outwho is asking the user to enter the phone number of acustomer?Where is an error message is printed in case thecustomer ID does not exists?Who is responsible to update the files? etc.

⇒ A well-designed program pushes responsibility from clientcode to server code

⇒ Client code thus expresses the meaning of computations, notdetails of computations

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/ / L i s t i n g 14.6 Class s p e c i f i c a t i o n f o r the Item c lass ( f i l e i tem . h ) .# i fnde f ITEM_H#define ITEM_Hclass I tem {

protected :char t i t l e [ 2 6 ] ;i n t id , quant , category ;

publ ic :void set ( const char ∗s , i n t num, i n t qty , i n t type ) ;i n t getQuant ( ) const ;i n t ge t Id ( ) const ;void get I tem ( char ∗ name, i n t &num, i n t & qty , i n t &type ) const ;void p r i n t I t e m ( ) const ;void i nc rQty ( i n t qty ) ;

} ;#endi f

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/ / L i s t i n g 14.7 Class s p e c i f i c a t i o n f o r the Customer c lass ( f i l e customer . h ) .# i fnde f CUSTOMER_H#define CUSTOMER_Hclass Customer {

char name[ 2 0 ] , phone [ 1 5 ] ;i n t count ;i n t movies [ 1 0 ] ;

publ ic :Customer ( ) ;void set ( const char ∗nm, const char ∗ph ) ;void addMovie ( i n t i d ) ;i n t removeMovie ( i n t i d ) ;void getCustomer ( char ∗nm, char ∗ph , i n t &cnt , i n t m[ ] ) const ;

} ;#endi f

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/ / L i s t i n g 14.8 Implementat ion o f c lass Item ( f i l e i tem . cpp ) .#include <iostream >using namespace std ;#include " i tem . h " / / t h i s i s a necess i ty

void I tem : : se t ( const char ∗s , i n t num, i n t qty , i n t type ){ s t r cpy ( t i t l e , s ) ; i d =num; quant=qty ; category=type ; }

i n t I tem : : getQuant ( ) const / / used by Inven to ry : : checkOut ( ){ return quant ; }

i n t I tem : : ge t Id ( ) const{ return i d ; } / / i n p r i n t R e n t a l ( ) , checkOut ( ) , checkIn ( )

void I tem : : get I tem ( char ∗ name, i n t &num,i n t & qty , i n t &type ) const / / used by F i l e : : saveItem ( )

{ s t r cpy (name, t i t l e ) ; num = i d ; q ty = quant ; type = category ; }

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void I tem : : p r i n t I t e m ( ) const / / used by p r i n t R e n t a l ( ){ cout . s e t f ( i os : : l e f t , i os : : a d j u s t f i e l d ) ;

cout . width ( 5 ) ; cout << i d ; / / i t knows i t s p r i n t formatscout . width ( 2 7 ) ; cout << t i t l e ;switch ( category ) { / / d i f f e r e n t i tem subtypescase 1: cout << " fea tu re " ; break ;case 2: cout << " comedy " ; break ;case 3: cout << " ho r ro r " ; break ; }cout << endl ; }

void I tem : : i nc rQty ( i n t qty ) / / used i n checkOut ( ) , checkIn ( ){ quant += qty ; }

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/ / L i s t i n g 14.9 Implementat ion o f c lass Customer ( f i l e customer . cpp ) .#include <iostream >using namespace std ;#include " customer . h " / / t h i s i s a necess i ty

Customer : : Customer ( ) { count = 0 ; }

void Customer : : se t ( const char ∗nm, const char ∗ph ){ s t r cpy (name,nm) ; s t r cpy ( phone , ph ) ; } / / i n appendCust ( )

void Customer : : addMovie ( i n t i d ){ movies [ count ++] = i d ; } / / i n appendCust ( ) , checkOut ( )

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i n t Customer : : removeMovie ( i n t i d ) / / used i n checkIn ( ){ i n t i dx ;

fo r ( i dx =0; i dx < count ; i dx ++) / / f i n d the moviei f ( movies [ i dx ] == i d ) break ;

i f ( i dx == count ) return 0; / / g ive up i f not foundwhile ( i dx < count − 1){ movies [ i dx ] = movies [ i dx + 1 ] ; / / s h i f t t a i l to the l e f t

i dx ++; }count−−; / / decrement movie countreturn 1; } / / r e p o r t success

void Customer : : getCustomer ( char ∗nm, char ∗ph , / / saveData ( )i n t &cnt , i n t m[ ] ) const / / I nven to ry : : getCustomer ( )

{ s t r cpy (nm, name ) ; s t r cpy ( ph , phone ) ; cn t = count ;fo r ( i n t i =0; i < count ; i ++)

m[ i ] = movies [ i ] ; }

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/ / L i s t i n g 14.10 Class s p e c i f i c a t i o n f o r the Inven to ry c lass ( f i l e i nven to ry . h# i fnde f INVENTORY_H#define INVENTORY_H#include " i tem . h "#include " customer . h "

class I nven to ry {

protected :enum { MAXM = 5 , MAXC = 4 } ; / / j u s t f o r the pro to typeI tem i t e m L i s t [MAXM] ;Customer c u s t L i s t [MAXC] ;i n t i temCount , custCount ;i n t i temIdx , cus t Idx ;

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publ ic :I nven to ry ( ) ;void appendItem ( const char ∗ t t l , i n t id , i n t qty , i n t cat ) ;void appendCust ( const char ∗ nm, const char ∗ ph , i n t cnt , const i n t ∗m) ;i n t get I tem ( Item& item ) ;i n t getCustomer ( char ∗ nm, char ∗ ph , i n t &cnt , i n t ∗m) ;void p r i n t R e n t a l ( i n t i d ) ;i n t checkOut ( i n t i d ) ;void checkIn ( i n t i d ) ;

} ;

#endi f

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/ / L i s t i n g 14.11 Implementat ion o f c lass Inven to ry ( f i l e i nven to ry . cpp ) .#include <iostream >using namespace std ;#include " i nven to ry . h " / / t h i s i s a necess i tyI nven to ry : : I nven to ry ( )

{ i temCount = i temIdx = 0; custCount = cus t Idx = 0; }void I nven to ry : : appendItem ( const char ∗ t t l , i n t id , i n t qty , i n t cat ){ i f ( i temCount == MAXM) / / used i n loadData ( )

{ cout << " \ nNo space to i n s e r t i tem " ; }else

{ i t e m L i s t [ i temCount ++ ] . se t ( t t l , id , qty , ca t ) ; } }

void I nven to ry : : appendCust ( const char ∗ nm, const char ∗ ph ,i n t cnt , const i n t ∗movie )

{ i f ( custCount == MAXC) / / used i n loadData ( ){ cout << " \ nNo space to i n s e r t customer " ; return ; }

c u s t L i s t [ custCount ++ ] . se t (nm, ph ) ;fo r ( i n t j =0; j < cnt ; j ++)

c u s t L i s t [ custCount −1] . addMovie ( movie [ j ] ) ; }c© A. Amer UML 25


i n t I nven to ry : : get I tem ( Item &item ) / / used i n saveData ( ){ i f ( i temIdx == itemCount )

{ i temIdx = 0; return 0; }i tem = i t e m L i s t [ i temIdx ++ ] ;return 1; }

i n t I nven to ry : : getCustomer ( char ∗ nm, char ∗ ph , i n t &cnt , i n t ∗m){ i f ( cus t Idx == custCount ) / / i n f indCustomer ( ) , saveData ( )

{ cus t Idx = 0; return 0; }c u s t L i s t [ cus t Idx ++ ] . getCustomer (nm, ph , cnt ,m) ;return 1; }

void I nven to ry : : p r i n t R e n t a l ( i n t i d ) / / used i n f indCustomer ( ){ fo r ( i temIdx = 0; i temIdx < itemCount ; i temIdx ++)

{ i f ( i t e m L i s t [ i temIdx ] . ge t Id ( ) == i d ){ i t e m L i s t [ i temIdx ] . p r i n t I t e m ( ) ; break ; } }

i temIdx = 0 ; }

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i n t I nven to ry : : checkOut ( i n t i d ) / / used i n processItem ( ){ fo r ( i temIdx = 0; i temIdx < itemCount ; i temIdx ++)

i f ( i t e m L i s t [ i temIdx ] . ge t Id ( ) == i d ) break ;i f ( i temIdx == itemCount ){ i temIdx = cus t Idx = 0; return 0; }i f ( i t e m L i s t [ i temIdx ] . getQuant ( ) == 0){ i temIdx = cus t Idx = 0; return 1; }i t e m L i s t [ i temIdx ] . i nc rQty ( −1) ;c u s t L i s t [ cus t Idx − 1 ] . addMovie ( i d ) ;i temIdx = cus t Idx = 0; return 2; }

void I nven to ry : : checkIn ( i n t i d ) / / used i n processItem ( ){ i f ( c u s t L i s t [ cus t Idx − 1 ] . removeMovie ( i d )==0)

{ cout << " Movie i s not found \ n " ; i temIdx = cus t Idx = 0; return ; }fo r ( i temIdx = 0; i temIdx < itemCount ; i temIdx ++)

{ i f ( i t e m L i s t [ i temIdx ] . ge t Id ( ) == i d ){ i t e m L i s t [ i temIdx ] . i nc rQty ( 1 ) ; break ; } }

i temIdx = cus t Idx = 0; cout << " Movie i s re tu rned \ n " ; }

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A case study: File class

/ / L i s t i n g 14.12 Class s p e c i f i c a t i o n f o r the F i l e c lass ( f i l e f i l e . h ) .# i fnde f FILE_H#define FILE_H#include " i tem . h "#include <fstream >using namespace std ;class F i l e {

fs t ream f ;s t a t i c void t r i m ( char b u f f e r [ ] ) ;enum { TWIDTH = 27 , IWIDTH = 5 , QWIDTH = 6 , NWIDTH = 18 , PWIDTH = 16 } ;

publ ic :F i l e ( const char name [ ] , i n t mode ) ;i n t get I tem ( char ∗ t t l , i n t &id , i n t &qty , char &type ) ;void saveItem ( const I tem &item ) ;i n t getCustomer ( char ∗name, char ∗phone , i n t &count , i n t ∗m) ;void saveCustomer ( const char ∗nm, const char ∗ph ,

i n t cnt , i n t ∗m) ;} ;#endi f

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A case study: File class implemetation

/ / L i s t i n g 14.13 Implementat ion o f c lass F i l e ( f i l e f i l e . cpp ) .#include <iostream >using namespace std ;#include " f i l e . h " / / t h i s i s a necess i ty

F i l e : : F i l e ( const char name [ ] , i n t mode){ f . open (name, mode ) ; / / used i n loadData ( ) , saveData ( )

i f ( f . f a i l ( ) ) / / i f ( f . is_open ( ) ) i s OK, too{ cout <<" F i l e i s not open \ n " ; e x i t ( 1 ) ; } }

i n t F i l e : : get I tem ( char ∗ t t l , i n t &id , i n t &qty , char &type ){ char b u f f e r [ 2 0 0 ] ; / / i n loadData ( )

f . get ( bu f fe r ,TWIDTH ) ;t r i m ( b u f f e r ) ;s t r cpy ( t t l , b u f f e r ) ; / / i t knows f i l e s t r u c t u r ef >> i d ; f >> qty ; f >> type ; f . g e t l i n e ( bu f fe r , 4 ) ;i f ( ! f ) return 0;return 1; }

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void F i l e : : saveItem ( const I tem &item ) / / i n saveData ( ){ char t t [ 2 7 ] ; i n t id , qty , type ;

i tem . get I tem ( t t , id , qty , type ) ;f . s e t f ( i os : : l e f t , i os : : a d j u s t f i e l d ) ;f . w id th (TWIDTH ) ; f << t t ; / / i t knows f i l e formatf . s e t f ( i os : : r i g h t , i os : : a d j u s t f i e l d ) ;f . w id th ( IWIDTH ) ; f << i d ;f . w id th (QWIDTH) ; f << qty ;switch ( type ) { / / d i f f e r e n t f o r d i f f e r e n t subtypes

case 1: f << " f \ n " ; break ;case 2: f << " c \ n " ; break ;case 3: f << " h \ n " ; break ; } }

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i n t F i l e : : getCustomer ( char ∗name, char ∗phone , i n t &count , i n t ∗m){ char b u f f e r [ 2 0 0 ] ; / / i n loadData ( )

f . get ( bu f fe r ,NWIDTH ) ;t r i m ( b u f f e r ) ;s t r cpy (name, b u f f e r ) ;f >> b u f f e r ; f >> count ; / / i t knows f i l e s t r u c t u r es t r cpy ( phone , b u f f e r ) ;fo r ( i n t i =0; i < count ; i ++)

f >> m[ i ] ;f . g e t l i n e ( bu f fe r , 2 ) ;i f ( ! f ) return 0;return 1; }

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void F i l e : : saveCustomer ( const char ∗nm, const char ∗ph ,i n t cnt , i n t ∗m) / / i n saveData ( )

{ f . s e t f ( i os : : l e f t , i os : : a d j u s t f i e l d ) ; f . w id th (NWIDTH ) ;f << nm;f . s e t f ( i os : : r i g h t , i os : : a d j u s t f i e l d ) ; f . w id th (PWIDTH ) ;f << ph << endl << cnt ; / / i t knows f i l e s t r u c t u r efo r ( i n t i =0; i < cnt ; i ++){ f . w id th ( 6 ) ; f << m[ i ] ; }f << endl ; }

void F i l e : : t r i m ( char b u f f e r [ ] ) / / i n get I tem ( ) , getCustomer ( ){ fo r ( i n t j = s t r l e n ( b u f f e r )−1; j >0; j −−)

i f ( b u f f e r [ j ]== ’ ’ | | b u f f e r [ j ]== ’ \ n ’ )b u f f e r [ j ] = ’ \0 ’ ;

elsebreak ; }

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A case study: store class

/ / L i s t i n g 14.14 Class s p e c i f i c a t i o n f o r the Store c lass ( f i l e s to re . h ) .# i fnde f STORE_H#define STORE_H#include " i nven to ry . h "#include " f i l e . h "

class Store {publ ic :

void loadData ( Inven to ry &inv ) ;i n t f indCustomer ( Inven to ry& inv ) ;void processItem ( Inven to ry& inv ) ;void saveData ( Inven to ry &inv ) ;

} ;#endi f

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A case study: store class implementation

/ / L i s t i n g 14.15 Implementat ion o f c lass Store ( f i l e s to re . cpp ) .#include <iostream >using namespace std ;#include " s to re . h " / / t h i s i s a necess i ty

void Store : : loadData ( Inven to ry &inv ){ F i l e i temsIn ( " Item . dat " , i os : : i n ) ; / / i tem database

char t t l [ 2 7 ] , category ; i n t id , qty , type ; / / i tem datacout << " Loading database . . . " << endl ;while ( i temsIn . get I tem ( t t l , id , qty , category )==1) / / read i n{ switch ( category ) { / / se t category f o r the subtype

case ’ f ’ : type = 1; break ;case ’ c ’ : type = 2; break ;case ’ h ’ : type = 3; break ; }

i nv . appendItem ( t t l , id , qty , type ) ; }F i l e cus t I n ( " Cust . dat " , i os : : i n ) ; / / customer databasechar name[ 2 5 ] , phone [ 1 5 ] ; i n t movies [ 1 0 ] , count ;while ( cus t I n . getCustomer (name, phone , count , movies )==1){ i nv . appendCust (name, phone , count , movies ) ; } } / / pump data

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i n t Store : : f indCustomer ( Inven to ry& inv ){ char b u f f e r [ 2 0 0 ] ; char name[ 2 5 ] , phone [ 1 3 ] ;

i n t count , movies [ 1 0 ] ;cout << " Enter customer phone ( or press Return to q u i t ) " ;c i n . g e t l i n e ( bu f fe r , 1 5 ) ;i f ( strcmp ( bu f fe r , " " )==0) return 0; / / q u i t i f no data enteredbool found = fa lse ;while ( i nv . getCustomer (name, phone , count , movies ) != 0)

{ i f ( strcmp ( bu f fe r , phone ) == 0) / / search f o r the phone{ found = t rue ; break ; } } / / s top i f phone found

i f ( ! found ){ cout << " \ nCustomer i s not found " << endl ;

return 1; } / / g ive up i f not foundcout . s e t f ( i os : : l e f t , i os : : a d j u s t f i e l d ) ;cout . width ( 2 2 ) ; cout << name << phone << endl ; / / p r i n t datafo r ( i n t j = 0 ; j < count ; j ++)

{ i nv . p r i n t R e n t a l ( movies [ j ] ) ; } / / p r i n t movie Id ’ scout << endl ;return 2; } / / success code

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void Store : : processItem ( Inven to ry& inv ){ i n t cmd, r e s u l t , i d ;

cout << " Enter movie i d : " ;c i n >> i d ; / / search a t t r i b u t ecout << " Enter 1 to check out , 2 to check i n : " ;c in >> cmd ;i f (cmd == 1){ r e s u l t = inv . checkOut ( i d ) ; / / analyze r e t u r n value

i f ( r e s u l t == 0) / / not foundcout << " Movie i s not found " << endl ;else i f ( r e s u l t == 1) / / out o f s tockcout << " Movie i s out o f s tock " << endl ;else / / i t i s a success

cout << " Renting i s conf i rmed \ n " ; }else i f (cmd == 2)inv . checkIn ( i d ) ; / / feedback i n checkIn ( )c in . get ( ) ; } / / e l i m i n a t e CR from l i n e

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void Store : : saveData ( Inven to ry &inv ){ F i l e itemsOut ( " I tem . out " , i os : : out ) ; I tem item ; / / i tem f i l e

while ( i nv . get I tem ( i tem ) ) / / no i n t e r n a l s t r u c t u r ei temsOut . saveItem ( i tem ) ; / / save each i tem

F i l e custOut ( " Cust . out " , i os : : out ) ; / / customer output f i l echar name[ 2 5 ] , phone [ 1 3 ] ; i n t count , movies [ 1 0 ] ;cout << " Saving database . . . " << endl ;while ( i nv . getCustomer (name, phone , count , movies ) ) / / pump data

custOut . saveCustomer (name, phone , count , movies ) ; }

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