Class diagram, use case and sequence diagram

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Class diagram, Use case and Sequence diagram

Subhin [email protected]/

subhinvelayudhantwitter.com/111subruin.linkedin.com/in/Subhin P V8129076036

CLASSES• A class is the blueprint from which individual

objects are created.• A class is a description of a set of objects that

share the same attributes, operations, relationships, and semantics.

• Class contains Attributes and Methods.• A class object can be created to access class’

methods. – An object stores its state in fields– exposes its behavior through methods

CLASS DIAGRAM• Class Diagram is a pictorial representation of a

Class for better understanding of a class• Graphically, a class is rendered as a rectangle,

usually including its name, attributes, and operations in separate, designated compartments.

CLASS DIAGRAM

• CLASS NAME

• ATTRIBUTES

• METHODS

An example of CLASS DIAGRAM

• Person

• - eat(): void• - sleep(): void• - work(): void• -play():String

+ name : String# address : String# birthDate : Date/ age : Date

- ssn : int

public class Person{ public String name;protected String address;protected Date birthDate;derived Date age;private int ssn;

void eat(){}void sleep(){}void work(){}String play(){}

}

USE CASE

• a use case is a list of steps, typically defining interactions between a role (actor) and a system, to achieve a goal.

• The actor can be a human or an external system.

• the relationships between all (or a set of) the use cases and actors are represented in a Use Case Diagram

USE CASE DIAGRAM• It is a UML diagram.• A use case diagram at its simplest is a

representation of a user's interaction with the system and depicting the specifications of a use case.

• A use case diagram can portray the different types of users of a system and the various ways that they interact with the system.

USE CASE DIAGRAM

Use case diagram of a restaurant

SEQUENCE DIAGRAM

• Generally show the sequence of events that

occur. • Illustrates the objects that participate in a use

case and the messages that pass between them over time for one use case

SEQUENCE DIAGRAM(contd..)

Diagram: A sequence diagram of request and response between a patient and a receptionist

SEQUENCE DIAGRAM SYNTAX

SEQUENCE DIAGRAM(contd..)• COMPONENTS OF A SEQUENCE DIAGRAM

Sequence Diagram

MessagesActive objects

Activation Box LifelineControl Information

SEQUENCE DIAGRAM (important components)

• Active Objects:– Any objects that play a role in the system– Can be any object or class that is valid within the system– Can be an Actor that is external to the system and derives

benefits from the system

• Messages:– Used to illustrate communication between different active

objects.– Used when an object needs

• to activate a process of a different object• to give information to another object

SEQUENCE DIAGRAM (other components)

• Lifeline– Denotes the life of actors/objects over time during a

sequence• Focus of control (activation box)– Means the object is active and using resources during

that time period• Control information– Shows the control flow in the system– Creation and destruction of an object through

<<create>> and <<destroy>>

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