Dale Roberts

Object Oriented Programming using JavaObject Oriented Programming using Java

- OOD to OOP: ATM Case Study- OOD to OOP: ATM Case Study

Dale Roberts, LecturerComputer Science, IUPUIE-mail: droberts@cs.iupui.edu

Department of Computer and Information Science,School of Science, IUPUI

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Starting to Program the Classes of the ATM SystemStarting to Program the Classes of the ATM System

VisibilityVisibilityAttributes normally should be private, methods Attributes normally should be private, methods invoked by clients should be publicinvoked by clients should be publicVisibility markers in UMLVisibility markers in UML

A plus sign (+) indicates public visibilityA plus sign (+) indicates public visibilityA minus sign (-) indicates private visibilityA minus sign (-) indicates private visibility

NavigabilityNavigabilityNavigability arrows indicate in which direction an Navigability arrows indicate in which direction an association can be traversedassociation can be traversedBidirectional navigabilityBidirectional navigability

Associations with navigability arrows at both ends or no Associations with navigability arrows at both ends or no navigability arrows at all can be traversed in either directionnavigability arrows at all can be traversed in either direction

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Fig. 8.24 Fig. 8.24 | Class diagram with visibility markers.| Class diagram with visibility markers.

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Fig. 8.25 Fig. 8.25 | Class diagram with navigability arrows. | Class diagram with navigability arrows.

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Starting to Program the Classes of the ATM System (Cont.)Starting to Program the Classes of the ATM System (Cont.)

Implementing the ATM system from its UML Implementing the ATM system from its UML design (for each class)design (for each class)

Declare a Declare a publicpublic class with the name in the first class with the name in the first compartment and an empty no-argument constructorcompartment and an empty no-argument constructorDeclare instance variables based on attributes in the Declare instance variables based on attributes in the second compartmentsecond compartmentDeclare references to other objects based on Declare references to other objects based on associations described in the class diagramassociations described in the class diagramDeclare the shells of the methods based on the Declare the shells of the methods based on the operations in the third compartmentoperations in the third compartment

Use the return type Use the return type voidvoid if no return type has been specified if no return type has been specified

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Fig. 8.24 Fig. 8.24 | Class diagram with visibility markers.| Class diagram with visibility markers.

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7OutlineOutline

1 // Class Withdrawal represents an ATM withdrawal transaction

2 public class Withdrawal

3 {

4 // no-argument constructor

5 public Withdrawal()

6 {

7 } // end no-argument Withdrawal constructor

8 } // end class Withdrawal

withdrawal.java

Class for Withdrawal

Empty no-argument constructor

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Fig. 8.24 Fig. 8.24 | Class diagram with visibility markers.| Class diagram with visibility markers.

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9OutlineOutline

1 // Class Withdrawal represents an ATM withdrawal transaction

2 public class Withdrawal

3 {

4 // attributes

5 private int accountNumber; // account to withdraw funds from

6 private double amount; // amount to withdraw

7

8 // no-argument constructor

9 public Withdrawal()

10 {

11 } // end no-argument Withdrawal constructor

12 } // end class Withdrawal

withdrawal.java

Declare instance variables

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Fig. 8.25 Fig. 8.25 | Class diagram with navigability arrows. | Class diagram with navigability arrows.

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11OutlineOutline

1 // Class Withdrawal represents an ATM withdrawal transaction 2 public class Withdrawal 3 { 4 // attributes 5 private int accountNumber; // account to withdraw funds from 6 private double amount; // amount to withdraw 7 8 // references to associated objects 9 private Screen screen; // ATM’s screen 10 private Keypad keypad; // ATM’s keypad 11 private CashDispenser cashDispenser; // ATM’s cash dispenser 12 private BankDatabase bankDatabase; // account info database 13 14 // no-argument constructor 15 public Withdrawal() 16 { 17 } // end no-argument Withdrawal constructor 18 } // end class Withdrawal

withdrawal.java

Declare references to other objects

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Fig. 8.24 Fig. 8.24 | Class diagram with visibility markers.| Class diagram with visibility markers.

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13OutlineOutline

1 // Class Withdrawal represents an ATM withdrawal transaction 2 public class Withdrawal 3 { 4 // attributes 5 private int accountNumber; // account to withdraw funds from 6 private double amount; // amount to withdraw 7 8 // references to associated objects 9 private Screen screen; // ATM’s screen 10 private Keypad keypad; // ATM’s keypad 11 private CashDispenser cashDispenser; // ATM’s cash dispenser 12 private BankDatabase bankDatabase; // account info database 13 14 // no-argument constructor 15 public Withdrawal() 16 { 17 } // end no-argument Withdrawal constructor 18 19 // operations 20 public void execute() 21 { 22 } // end method execute 23 } // end class Withdrawal

withdrawal.java

Declare shell of a method with return type void

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AcknowledgementsAcknowledgementsDeitel, Java How to Program