Mermaid Class Diagrams

Class diagrams describe the structure of a system: entities (classes), their attributes, methods, and relationships. They are useful for documenting data structures, API schemas, and application architecture.

Basic Syntax

classDiagram
    class Task {
        +String id
        +String title
        +String status
        +Date createdAt
        +assign(userId: String)
        +complete()
    }

Attributes and Methods

Access Modifiers

classDiagram
    class User {
        +String id
        +String email
        -String passwordHash
        #String tenantId
        +getProfile() Profile
        -hashPassword(plain: String) String
    }

Relationships

classDiagram
    Animal <|-- Dog
    Animal <|-- Cat
    Animal : +String name
    Animal : +makeSound()*

    class Dog {
        +String breed
        +makeSound()
    }

    class Cat {
        +bool isIndoor
        +makeSound()
    }

Cardinality

classDiagram
    Project "1" --> "many" Task : contains
    Task "many" --> "1" User : assigned to
    User "1" --> "many" Project : member of

Interfaces and Enumerations

classDiagram
    class Serializable {
        <<interface>>
        +serialize() String
        +deserialize(data: String)
    }

    class TaskStatus {
        <<enumeration>>
        BACKLOG
        IN_PROGRESS
        REVIEW
        DONE
    }

    class Task {
        +TaskStatus status
        +serialize() String
        +deserialize(data: String)
    }

    Serializable <|.. Task
    Task --> TaskStatus

Example: FlowEra Architecture

classDiagram
    class Flow {
        +String id
        +String name
        +String tenantId
        +String statusModelId
        +createTask(data: CreateTaskDTO) Task
        +getTasks(filter: Filter) Task[]
    }

    class Task {
        +String id
        +String flowId
        +String title
        +String status
        +Properties properties
        +assign(userId: String)
        +updateStatus(status: String)
    }

    class StatusModel {
        +String id
        +String name
        +StatusDef[] statuses
        +getStatus(label: String) StatusDef
        +isValidTransition(from: String, to: String) bool
    }

    class FieldTemplate {
        +String id
        +String flowId
        +String name
        +FieldType type
        +bool required
        +validate(value: any) bool
    }

    Flow "1" --* "many" Task : contains
    Flow --> StatusModel : uses
    Flow "1" --> "many" FieldTemplate : defines