{"id":5004,"date":"2024-06-10T21:05:40","date_gmt":"2024-06-10T19:05:40","guid":{"rendered":"https:\/\/oopm.org\/?page_id=5004"},"modified":"2025-01-14T12:43:42","modified_gmt":"2025-01-14T11:43:42","slug":"10-2a-abstract-flight","status":"publish","type":"page","link":"https:\/\/oopm.org\/?page_id=5004","title":{"rendered":"10.2 Flight example"},"content":{"rendered":"
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In this chapter we illustrate nested classes by an example in the domain of flights and flight routes.<\/p>\n\n\n\n

An airline company like SAS has a timetable with all their flight routes with flights, e.g. SK SK 1926 from Aarhus in Denmark to Oslo in Norway, and SK 1927 from Oslo to Aarhus.<\/p>\n\n\n\n

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A time table is used for two different purposes: as a basis for bookings, e.g. as in the chapter on travel bookings, and as a basis for a website that shows the status of flights at a specific airport, i.e. whether flights are on time, cancelled, delayed, have a new scheduled time of arrival, have arrived and at what time, etc.<\/p>\n\n\n\n

Time tables, flight routes and flights are obviously represented by objects. A timetable has an entry for each of the different flight routes, and in the model each entry is represented by an object of class FlightRoute<\/code>:<\/p>\n\n\n\n

timeTable: obj<\/strong> \n   entries: obj<\/strong> OrderedList(FlightRoute)<\/code><\/pre>\n\n\n\n
Each\u00a0FlightRoute<\/code>\u00a0object has attributes that represent the flight number of the flight route, the source and destination airports, the scheduled departure and arrival time, and scheduled flying time. The flights of a route is represented by a list of\u00a0Flight<\/code>\u00a0objects for each\u00a0FlightRoute<\/code>\u00a0object.<\/p>\n\n\n\n
class<\/strong> FlightRoute(flightNumber, origin, destination: var<\/strong> String): \n   scheduledDepartureTime: var<\/strong> TimeOfDay           \n   scheduledArrivalTime: var<\/strong> TimeOfDay \n   setTime(dt: var<\/strong> TimeOfDay, at: var<\/strong> TimeOfDay):\n<\/mark>      scheduledDepartureTime := dt\n      scheduledArrivalTime := at \n   \n   flights: obj<\/strong> OrderedList(Flight)<\/code><\/pre>\n\n\n\n
scheduledDepartureTime<\/code> and scheduledArrivalTime<\/code> are used for showing flight status, at airports or at the flight status website of the airline company. The type TimeOfDay<\/code> is defined in section