12 UML

Phases of Software Engineering¶

flowchart LR
a[Requirement Gathering] -->
b[Requirement Analysis] -->
d["Design<br />(UML Diagrams)"] -->
Coding -->
Testing -->
Deployment -->
Support

UML¶

Unified Modeling Language

Use Case Diagram¶

Actors¶

classes

could be

1. users of the system
2. external system
3. physical environment

Properties

1. unique name
2. description (optional)

Use Cases¶

basically like functions

properties

1. unique name
2. participating actors
3. entry conditions
4. exit conditions
5. event flow
6. exceptional cases

<<extends>>¶

for exceptions/showing use cases that are rarely used

The direction of a <<extends>> relationship is to the extended use case

<<includes>>¶

for use cases that require/depend on another use case

The direction of a <<includes>> relationship is to the using use case (unlike <<extends>> relationships).

Class Diagram¶

Access Specifiers¶

• (nothing) default
• - private
• + public
• # protected

Connections¶

• association

  • can be 1-way or 2-way
  • can be one-one or many-many \(1-1, \quad 5\ldots* - *, \quad *- 3\ldots *, \quad * - *\)
  • arrow from a towards b, means that a depends on b

• aggregation

• composition (strong aggregation)
• inheritance
  • class inheritance
  • interface inheritance

Example¶

classDiagram
Interface <|.. Base: implements
Base <|-- Teacher
Base <|-- Student
Base <.. Tester
ClassRoom *-- Teacher
ClassRoom o-- Student
class Interface {
    <<interface>>
    +func() void
}
class Base {
    <<abstract>>
    #var : int
    +func() void
}
class Tester {
    +main() void
}

Sequence Diagram¶

Shows the interactions bw the classes/objects

calls are solid, returns are dashed

sequenceDiagram
autonumber

activate d

d ->>+ p: Discharge Advice

activate r

p ->>- r: Discharge Request

r ->> + pd: Check Details
pd -->> - r: Detailed Summary
r ->> r:  Prepare Bill
r -->>+ p: Send Bill
p ->>- r: Request Discount
r ->> d: Check Possibility of discount
d -->> r: Approve Discount

deactivate d

r ->> r: Update bill
r ->>+ p: Send bill
p -->>- r: Pay bill
r ->> +pd: Update Bill
deactivate pd

activate p
r ->> p: Discharge note

deactivate r

p ->> + Ward: Show note
Ward -->> - p: Discharge
deactivate p

%% participant
participant d as Doctor
participant p as Patient
participant r as Reception
participant pd as Patient Database

State Diagrams¶

stateDiagram-v2
[*] --> dr
dr --> cp: Patient Register
cp --> er: Resign
er --> [*]

state "Doctor Registration" as dr
state "Check Patient" as cp
state "End Service" as er

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