Erlang Pollution Server OTP

Simple project wirtten in Erlang. It contains four modules:

• pollution
• gen_server
• server_supervisor
• pollution_value_collector_gen_statem

Module pollution:

It contains functionalities useful while storing data from weather stations.

Module gen_server:

It contains pollution server functionality.

Module server_supervisor

It restarts gen_server module or pollution_value_collector_gen_statem module if they crash.

pollution_value_collector_gen_statem:

A module that implements a state machine, allowing to insert many Measurements to a selected station. If proper order of operations is not preserved, the module crashes and is being restarted by server_supervisor.

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gen_server available functions:

1. addStation

addStation(Name, Coordinates)

Function is adding station with Name and Coordinates.

• Name must be distinctive
• Coordinates must be disctinctive

2. addValue

addValue(StationIdentifier, MeasurementDate, MeasurementType, MeasurementValue)

Function is adding Measurement build by MeasurementDate, MeasurementType and MeasurementValue. StationIdentifier is a Name or a Coordinate of a station.

3. removeValue

removeValue(StationIdentifier, MeasurementDate, MeasurementType)

Deletes Measurement from station with StationIdentifier with MeasurementDate and MeasurementType.

4. getOneValue

getOneValue(StationIdentifier, MeasurementDate, MeasurementType)

Gets a value of the Measurement that has MeasurementDate and MeasurementType from station with StationIdentifier.

5. getStationMean

getStationMean(StationIdentifier, MeasurementType)

Gets mean value of the Measurements that has MeasurementType from station with StationIdentifier.

6. getDailyMean

getDailyMean(Date, Type)

Gets mean value of the Measurements that has Date and Type

7. getHourlyMean

getHourlyMean(StationIdentifier, Hour, Type)

Gets mean value of the Measurements that has Hour and Type from StationIdentifier

8. getLastMeasurement

getLastMeasurement(StationIdentifier, Type)

Gets last value of the Measurements that has Type from StationIdentifier

9. getMeasureMaxValue

getMeasureMaxValue(StationIdentifier, Type)

Gets biggest value of the Measurements that has Type from StationIdentifier

pollution_value_collector_gen_statem available functions:

1. set_station

set_station(Name, Coordinates)

Begins the operation, can not be used after add_value. Creates new Station with Name and Coordinates or finds Station with Name if Station with given Name exists.

2. add_value

add_value(Date, Type, Value)

Adds new Measurement to Measurement table. Can not be used as the first operation and can't be used after using store_data.

3. store_data

store_data()

Saves all Measurements saved in Measurement table. Can not be used as the first operation and can not be used after store_data.