Unified Modelling Language Class Diagram.pptx

Class Diagram

1. Class Diagram Dr.J.Jospin Jeya

2. Key Components of a Class Diagram A Class Diagram is a type of static structure diagram that describes the structure of a system by showing its classes, their attributes, methods, and relationships between the objects. It is a fundamental diagram in object-oriented modeling. Key Components of a Class Diagram: Class : Represented by a rectangle divided into three parts: Top part : Name of the class. Middle part : Attributes (variables) of the class. Bottom part : Methods (functions) of the class. Attributes : Represent the properties of a class. Example: name: String, balance: Double Methods : Represent the behaviors or actions of a class. Example: deposit(), withdraw()

3. Cont … 4.Relationships : Association : Represents a relationship between two classes. Solid line connecting the classes. Inheritance (Generalization): Indicates a "is-a" relationship (a subclass inherits from a superclass). Solid line with a hollow arrowhead pointing to the parent class. Aggregation : Represents a "whole-part" relationship, where the child can exist independently of the parent. Solid line with a hollow diamond . Composition : A stronger form of aggregation where the child cannot exist without the parent. Solid line with a filled diamond . Dependency : A class depends on another class. Dotted line with an arrow .

4. Example: Class Diagram for an Online Banking System Classes: BankAccount Attributes: accountNumber : String balance: Double Methods: deposit(amount: Double): void withdraw(amount: Double): void getBalance (): Double Customer Attributes: name: String address: String Methods: createAccount (): BankAccount login(): Boolean updateDetails (): void

5. Cont.. 3.Transaction Attributes: transactionId : String amount: Double transactionDate : Date Methods: processTransaction (): Boolean Admin Attributes: adminId : String Methods: generateReport (): void manageAccount (): void Relationships: Bank Account is associated with Customer (a customer can have multiple bank accounts). Transaction is dependent on BankAccount (a transaction involves a bank account). Admin has a relationship with BankAccount (admin can manage customer accounts).