Syntax

---
title: Bank example
---
classDiagram
    class BankAccount
    BankAccount : +String owner
    BankAccount : +Bigdecimal balance
    BankAccount : +deposit(amount)
    BankAccount : +withdrawal(amount)

  classDiagram
    class BankAccount
    BankAccount : +String owner
    BankAccount : +Bigdecimal balance
    BankAccount : +deposit(amount)
    BankAccount : +withdrawal(amount)

Define a class

class label

classDiagram
    class Animal["Animal with a label"]
    class Car["Car with *! symbols"]
    Animal --> Car

  classDiagram
    class Animal["Animal with a label"]
    class Car["Car with *! symbols"]
    Animal --> Car

Define members of a class

classDiagram
class BankAccount{
    +String owner
    +BigDecimal balance
    +deposit(amount)
    +withdrawal(amount)
}

  classDiagram
class BankAccount{
    +String owner
    +BigDecimal balance
    +deposit(amount) bool
    +withdrawal(amount) int
}

区别 attributes 和 methods 的方法是，带()的是 methods。

generic types

classDiagram
class Square~Shape~{
    int id
    List~int~ position
    setPoints(List~int~ points)
    getPoints() List~int~
}

Square : -List~string~ messages
Square : +setMessages(List~string~ messages)
Square : +getMessages() List~string~
Square : +getDistanceMatrix() List~List~int~~

  classDiagram
class Square~Shape~{
    int id
    List~int~ position
    setPoints(List~int~ points)
    getPoints() List~int~
}

Square : -List~string~ messages
Square : +setMessages(List~string~ messages)
Square : +getMessages() List~string~
Square : +getDistanceMatrix() List~List~int~~

Visibility

在 attributes 和 methods 前加上这些符号来表示更多含义：

• + Public
• - Private
• # Protected
• ~ Package/Internal

在 () 或者 return type 后面加下面两个符号还能表示 abstract 和 static:

• - Abstract e.g.: someAbstractMethod()* or someAbstractMethod() int*
• $ Static e.g.: someStaticMethod()$ or someStaticMethod() String$

Define Relationship

[classA][Arrow][ClassB]

还可以加标签来描述两个类之间关系：

[classA][Arrow][ClassB]:LabelText

classDiagram
classA --|> classB : Inheritance
classC --* classD : Composition
classE --o classF : Aggregation
classG --> classH : Association
classI -- classJ : Link(Solid)
classK ..> classL : Dependency
classM ..|> classN : Realization
classO .. classP : Link(Dashed)

  classDiagram
    classA --|> classB : Inheritance
    classC --* classD : Composition
    classE --o classF : Aggregation
    classG --> classH : Association
    classI -- classJ : Link(Solid)
    classK ..> classL : Dependency
    classM ..|> classN : Realization
    classO .. classP : Link(Dashed)

Define Namespace

Cardinality / Multiplicity on relations

Annotations on classes

• <<Interface>> To represent an Interface class
• <<Abstract>> To represent an abstract class
• <<Service>> To represent a service class
• <<Enumeration>> To represent an enum

classDiagram
class Shape
<<interface>> Shape
Shape : noOfVertices
Shape : draw()

  classDiagram
class Shape
<<interface>> Shape
Shape : noOfVertices
Shape : draw()

Setting the direction of the diagram

direction RL

Note

classDiagram
    note "This is a general note"
    note for MyClass "This is a note for a class"
    class MyClass{
    }

  classDiagram
    note "This is a general note"
    note for MyClass "This is a note for a class"
    class MyClass{
    }