To design a class model to represent a simple air traffic controller scenario. Itz not necessary to consider any specific implementation details
Air traffic control system: which organises and regulates the process of landing aircraft at an airport. The system has a holding pattern, where aircraft 1st appear when they intend to land. From the holding pattern, aircraft can be instructed to move to the final approach corridor, where they will then land. A number of instructions can be issued to aircraft:
· promote from holding pattern to final approach · demote from final approach to holding pattern · emergency promote to front of file approach · (from file approach) Abort landing, return to back of final approach · redirect to other airport
Time is stimulated through a 'time ticks' in which moves are made. Only one instruction may be issued to each aircraft per time 'tick'. Instructions are carried out immediately.
The holding pattern and final; approach corridor can only support a certain number of aircraft before the flight lanes become overcrowded and collisions are certain. Furthermore, each aircraft has FINITE AMOUNT OF FUEL-THEY MUST HAVE ENOUGH FUEL TO MOVE FROMONE STAGE OF the traffic control system to the other to land safely, otherwise they will crash. There is also an upper limit placed on the amount of fuel a plane can carry before they can safely land.
An Aircraft
for the purpose of traffic control, an aircraft can be considered to require only a flight number (QF123) and a fuel amount. Other attributes may be added as u see fit.
The holding pattern: is an area where the aircraft waiting to land can circle until there number is called for final approach. There is no specific rule for where an aircraft may join the holding pattern, however under normal circumstances they may only be promoted to final approach at a particular position.
In emergency situation, it should be possible to specify which plane to take out of the holding pattern. Eg: if a plane is low on fuel, it should be possible to issue a special instruction to allow it to be taken out of the queue.
The final approach corridor: A simple queue where under normal conditions, aircraft enter at the tail and are taken off the head for landing on the runaway. However, under emergency circumstances, an aircraft may be added to the head of the final approach corridor for immediate landing.
"Gaps" can appear in the approach corridor if no plane has been instructed to occupy a place. Conversely, if 2 aircraft are instructed to enter the approach corridor from the same end in the one time tick, a collision will occur.
When an aircraft reaches the end of the final approach corridor, it can be assumed that it will attempt a landing on the runaway.
Fuel, weather, emergency, and disasters: Under normal circumstanced, each aircraft will use one unit of fuel per time tick. However, changing weather conditions may influence fuel consumption and allowable behaviour. For example:
*if there is windshear, aircraft on final approach may use more fuel than normal *if there is snow, the runaway will close and all planes must be either moved to the holding pattern or diverted to other airports. *certain weather conditions may also increase the risk of accidents while landing.
HINTS: *make use of status variables to hold information like whether an aircraft has already been issued an instruction this time tick ,and what the weather, runaway status etc. are. *use an exception to model game-ending disasters(such as plane crashes) *separate your "controller" class from the user interface of the program. In the design document, there is no need for a driver class to be shown *Design ur data structure classes(holding pattern and final approach) to work as simple data holders. Have a separate "controller" class which is the one that takes instruction and manipulates the structures in the appropriate manner, while ensuring rules are followed and status information is updated.
i just dont kno what classes to use and what attributes and methods to use from the information provided...
i kno u can have a class called Aircraft which have attributes such as int fuel account and int flight number and methods getFuelAccount() and getFlightNumber() ....is that correct am i going in the right direction..i just dont kno what other classes to use
Classes represent things and methods represent actions that those things can perform. For the purposes of this question, you need first to identify the 'things'. These will be your classes:
Air traffic control system: which organises and regulates the process of landing aircraft at an airport. The system has a holding pattern, where aircraft 1st appear when they intend to land. From the holding pattern, aircraft can be instructed to move to the final approach corridor, where they will then land. A number of instructions can be issued to aircraft:
You may be able to identify more. Chances are you will find too many but that is not a problem because you can always cross them off if you don't need them. Better that than not to spot them in the first place.
Having identified a number of classes you need to identify the actions carried out by those objects, for instance (helpfully the question states a number of the actions for you):
· promote from holding pattern to final approach · demote from final approach to holding pattern · emergency promote to front of file approach · (from file approach) Abort landing, return to back of final approach · redirect to other airport
There may be more. These will be your methods. The final part is to associate which things are responsible for carrying out which actions. From this you can derive your method definitions. As well as the Aircraft object you identified you may also find you need a HoldingPattern object which might have an addAircraft method that takes an Aircraft and checks that the maximum number of Aircraft permitted in the HoldingPattern has not been exceeded. It may also have a promote method and some others.
Get a pencil and paper and identify the possible things that might happen to an Aircraft. This too will help identify objects, what they can do and how they interact.
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