Class Diagram – Weather Station
In object-oriented design, a class diagram represents the static structure of a system by showing its classes, their attributes, methods, and the relationships between the classes. Below is a breakdown of the key components for a Weather Station system.
1. Class: WeatherStation
Attributes:
- stationId: String
- location: String
- installationDate: Date
Methods:
- collectData(): void
- generateReport(): Report
- sendAlert(): void
Responsibilities:
- Central class that coordinates all sensor readings
- Interfaces with external users and systems
- Triggers alerts based on sensor data thresholds
2. Class: Sensor
Attributes:
- sensorId: String
- type: String (e.g., temperature, humidity, wind)
- unit: String
- lastCalibrated: Date
Methods:
- readData(): float
- calibrate(): void
- getStatus(): String
Responsibilities:
- Abstract class (or base class) for all sensor types
- Provides methods to read and calibrate data
3. Subclasses of Sensor:
These inherit from the Sensor class and implement specialized behavior.
a. TemperatureSensor
-
Additional Methods: getTemperatureInCelsius()
b. HumiditySensor
-
Additional Methods: getHumidityPercentage()
c. WindSpeedSensor
-
Additional Methods: getWindSpeedInKmPerHour()
d. RainfallSensor
-
Additional Methods: getRainfallInMM()
4. Class: DataLogger
Attributes:
- logId: String
- timestamp: Date
- data: Map<String, Float>
Methods:
- logData(sensorType: String, value: float): void
- retrieveLogs(startDate: Date, endDate: Date): List<DataLogger>
Responsibilities:
- Stores the historical weather data
- Provides access to past readings for reporting and analysis
5. Class: Report
Attributes:
- reportId: String
- generatedOn: Date
- reportType: String (Daily, Weekly, Monthly)
Methods:
- displayReport(): void
- exportToCSV(): File
Responsibilities:
- Generates and formats weather data reports
- Supports multiple formats (table, chart, file)
6. Class: AlertSystem
Attributes:
- alertId: String
- thresholdMap: Map<String, Float>
- recipients: List<String>
Methods:
- checkForAlert(data: Map<String, Float>): void
- notifyUsers(message: String): void
Responsibilities:
- Monitors weather data for abnormal values
- Sends alerts to users or external systems
7. Class: User
Attributes:
- userId: String
- name: String
- email: String
- role: String (Administrator, Observer)
Methods:
- login(): Boolean
- viewData(): void
- requestReport(): Report
Responsibilities:
- Represents a person interacting with the system
- Role determines access level and features
8. Class: MaintenanceTechnician (inherits User)
Additional Methods:
- performCalibration(sensorId: String): void
- replaceSensor(sensorId: String): void
Responsibilities:
- Extends the User class with additional capabilities
- Can perform technical maintenance tasks
Relationships Overview:
- WeatherStation “has a” Sensor → One-to-many association
- Sensor “is a” superclass of specialized sensors → Inheritance
- WeatherStation “uses” DataLogger and Report → Dependency/association
- AlertSystem “uses” WeatherStation data → Association
- User “interacts with” WeatherStation → Association
- MaintenanceTechnician “extends” User → Inheritance
Explanation for Students:
- A class diagram represents how different parts of the Weather Station system are organized and how they communicate.
- Inheritance is used to create a hierarchy among sensor types, reducing duplication.
- The WeatherStation class acts as the central hub, coordinating with sensors, logs, users, and alert systems.
- Modularity and separation of concerns are maintained by assigning distinct roles to each class (e.g., reporting, logging, alerts).
