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Car driver want to have a way to know what is the best price gas station in their surrounding while travelling in order to save money or what is the nearest one for getting fuel as quick as possible in case of need.
For meeting this need the EZgas mobile application will be developed. In this application there is a GoogleMaps interface that shows all the gas station in a default radius (that can be set to a different value by the user) with the relative price for the different kind of fuel.
Everytime the fuel price of a gas station change, an employee has to update the application with the new price. There could also be application without prices.
Stakeholders
Stakeholder name
Description
Car Driver
Has the interest in purchasing fuel at the lowest price possible
Gas Station
Has the interest to 'advertise' itself as a competitive alternative
GPS system
Locates the driver
GoogleMaps
Show what is in the surrounding
DataBase
Record all current prices for fuel
Context Diagram and interfaces
Context Diagram
Interfaces
Actor
Logical Interface
Physical Interface
Car Driver
GUI
Screen
Gas Station
GUI
Screen
GoogleMaps
GoogleMaps API
Internet
GPS system
GPS API
Geolocation system
DataBase
SQL
Interntet
Stories and personas
Mr. Smith is driving to go to the sea. He has enough fuel to complete most of it's long trip, so it is possible for him to skip some gas station an waiting for the cheapest one. Hence he starts its EZgas application by tapping on the icon. He has no need to sets the parameters (gas and radius), nor to login as "car driver" role, since is not the first time he use the app. By a quick look to the screen he discover that the third station, as the bird fly, in the defined radius is the most convenient, so he decide to skip the first two along its route.
Mark is a freshman just hired in a big company after completing its studies as computer engineer. Being the first days he is a little nervous, so lately he forget to have a look to the fuel level indicator of is car. He is in a hurry but it's fuel is not at all sufficient to reach his new office. So he tap on the EZgas icon and set the radius parameter to the same value of the remaining kilometers he can travel, without caring about the price. Luckily, EZgas discover an appropriate station, and Mark won't be late.
Harry is the manager of a gas station. It's duty, among others, it's to update everymorining the price of the gas station he works for in the EZgas application. In order to do this he open the EZgas app, select the profile "gas station owner", and type the price in the apposite window of his gas station.
Functional and non functional requirements
Functional Requirements
ID
Description
FR0
Log the user
FR0.0
Log the user in the role of "car driver"
FR0.1
Log the user in the role of "gas station owner"
FR0.2
Remember the user for the next time
FR0.3
Log out the use
FR1
Display the gas stations and relative price whithin a certain radius that sell the desired kind of fuel
FR1.1
Display the gas stations and relative price outside the radius if none is within it
FR2
Display the stations (with prices) according to the coloring rules while car driver is moving
FR2.1
Compute the nearest station
FR2.2
Compute the cheapest station
FR3
Compute and Display the best path toward the gas station selected by the user
FR4
Keep prices up to date
FR4.1
Record and updates price when gas stations manager enter it in the application
coloring rules for gas stations
green : the chepest
blue : the nearest
grey : station with no price indication
yellow : all other stations
Non Functional Requirements
ID
Type
Description
Refers to
NFR1
Usability
Application should be used with no training by any car driver
All FR
NFR2
Performance
All functions should complete in < 0.5 sec
All FR
NFR3
Portability
The application runs on Android (from KitKat on) and iOS (from 12 on)
All FR
Use case diagram and use cases
Use case diagram
Use Cases
Use case 1, UC1 - FR0.0 Log the user and acquires parameters - FR0.2 Remember the user for the next time
Actors Involved
Car Driver
Precondition
The user has installed the EZgas app
Post condition
The user role and eventually parameters are initialized, the user role is in the cache memory of the application
Nominal Scenario
The app request the type of role, the user select "car driver", the app request radius and kind of fuel (step that the user can skip). The app save in its portion of cache memory user's data
Variants
No internet connection available, process stalled
Use case 2, UC2 - FR0.0 Log the user in role of "gas station owner" - FR0.2 Remember the user for the next time
Actors Involved
Gas station manager
Precondition
The user has installed the EZgas app
Post condition
The user role and parameters are initialized, the user role is in the cache memory of the application
Nominal Scenario
The app request the type of role, the user select "gas station owner", the app request to select among the existing gas station. An out of band verification is performed. The app save in its portion of cache memory user's data
Variants
No internet connection available -> process stalled, No confirmation OOB -> process pending
Use case 3, UC3 - FR0.3 Log out the user
Actors Involved
Car Driver/Gas station manager
Precondition
The user has installed the EZgas app and logged in any role
Post condition
The user is logged out
Nominal Scenario
The user tap on the log out button
Variants
No internet connection available -> process stalled
Use case 4, UC4 - FR1,FR1.1 Display gas stations and prices
Actors Involved
Car Driver, GPS, GoogleMaps
Precondition
The user has installed the EZgas app, the user has tapped on the app icon
Post condition
Station(s) and price(s) are displayed
Nominal Scenario
The search for the station withing the given radius through the joint use of the GPS and GoogleMaps API and then display results
Variants
No station in the radius->search for the nearest station outside the radius , No internet connection available, process stalled
Use case 5, UC5 - FR2.2 Compute the cheapest station
Actors Involved
Car Driver, GPS, GoogleMaps
Precondition
The user has installed the EZgas app, the user has tapped on the app icon
Post condition
Station(s) and price(s) are displayed
Nominal Scenario
The search for the station within the given radius through the joint use of the GPS and GoogleMaps API, then sort just the one with price in ascending order, finally returns the cheapest one
Variants
No station in the radius->search for the nearest station outside the radius, All stations lack the price indication->return the nearest with a proper warning message, No internet connection available, process stalled
Use case 6, UC6 - FR2.1 Compute the nearest station
Actors Involved
Car Driver, GPS, GoogleMaps
Precondition
The user has installed the EZgas app, the user has tapped on the app icon
Post condition
Station(s) and price(s) are displayed
Nominal Scenario
The search for the station within the given radius through the joint use of the GPS and GoogleMaps API, then sort them in ascending order of distance, finally returns the nearest one
Variants
No station in the radius->search for the nearest station outside the radius, No internet connection available, process stalled
Use case 7, UC7 - FR2 Display the station (with prices) according to the coloring rules while car driving is moving
Actors Involved
Car Driver, GPS, GoogleMaps
Precondition
The user has installed the EZgas app, the computation for the cheapest has been done, the computation for the nearest has been done
Post condition
Station(s) and price(s) are displayed colored
Nominal Scenario
After the app return the cheapest and nearest station indication it also colors it in green and blue respectively, others (with price) in yellow and the remaining (without price) in grey. Each time a new station enter in the radius the computation is performed again and the result updated and displayed
Variants
No internet connection -> process stalled
Use case 8, UC8 - FR3 Compute and Display the best path toward the gas station selected by the user
Actors Involved
Car Driver, GPS, GoogleMaps
Precondition
The user has installed the EZgas app, the co tapped the EZgap app icon, Stations have been displayed (an user can also choose a station before searching for nearest or cheapest)
Post condition
Best path/route with indications are displayed
Nominal Scenario
The user tap on a gas station icon and the system compute the best path from its position to the station, taking into account current traffic conditions
Variants
No internet connection -> process stall
Use case 9, UC9 - FR4 Keep prices up to date, FR4.1 Record and updates price when gas stations manager enter it in the application
Actors Involved
Gas station Manager
Precondition
The manager has installed the EZgas app, it's role has been verified, the manager has tapped on the EZgas app icon
Post condition
Gas station price updated
Nominal Scenario
The manager enter the daily price for fuel
Variants
No internet connection -> process stall
Relevant scenarios
Scenario 1 - UC2
Scenario ID: SC1
Corresponds to UC2
Description
Log the user in role of "gas station owner"
Precondition
The user has installed the EZgas app and tapped on the corresponding icon
Postcondition
Account created
Step#
Step description
1
The app request the type of role
2
The user select "gas station owner"
3
The app request to select among the existing gas station
4
The app display a TextForm for the city to search in
5
The user enter the city and get result displayed in a map formato
6
The user select the gas station he is the manager of
7
The app ask the user, displaying another TextForm, an "official email" of the gas station for sending a OOB confirmation code
8
The user enter the email address
9
The user receive the code by email
10
The app show a PasswordForm where to put the received secret code
11
The user enter the code
12a
If the code is corret the user is logged as "gas station" user
12b
If the code is not correct the app ask to enter in again up to a maximum of 5 times, then it close itself
Scenario 2 - UC5
Scenario ID: SC2
Corresponds to UC5
Description
Compute the cheapest station
Precondition
The user has installed the EZgas app, the user has tapped on the app icon
Postcondition
The cheapest station is displayed in green
Step#
Step description
1
The app search for all the gas station within the user defined radius or in the default radius if the latter is not defined
2
The app discard for its computation all the station without prices or that doesn't sell the fuel type defined by the car driver
3b
If all stations are priceless the procedure ends here and no station is colored
3
The app get all the prices for the type of fuel of interest and sort them in ascending order
4
The app colors in green the icon of the cheapest gas station
5
Each time a new station enter in the radius the computation is performed again
Scenario 3 - UC6
Scenario ID: SC3
Corresponds to UC6
Description
Compute the nearest station
Precondition
The user has installed the EZgas app, the user has tapped on the app icon
Postcondition
The nearest station is displayed in blue
Step#
Step description
1
The app search for all the gas station within the user defined radius or in the default radius if the latter is not defined
2
The app discard for its computation all the station that doesn't sell the fuel type defined by the car driver
3b
If all stations are doesn't sell that fuel type the procedure end here and no station is colored
3
The app compute the distance towards all of the filtered stations and sort them in ascending order
4
The app colors in blue the icon of the nearest gas station
5
Each time a new station enter in the radius the computation is performed again
Scenario 4 - UC9
Scenario ID: SC4
Corresponds to UC9
Description
Record and updates price when gas stations manager enter it in the application
Precondition
The gas station manager has installed the EZgas app, he has tapped on the app icon and entered is profile
Postcondition
The price is updated
Step#
Step description
1
The user tap on the UpdatePrice Button
2
The app shows a TextForm in wich to insert the new price
3
The manager enter the new price
4
The EZgas application update its database
5
The new price is displayed on the maps of all users
Glossary
System Design
GPS system is in the hardware device in wich the app runs
The Database is kept and managed internally by the application
