/tutorial/parking/parking.e

  1class PARKING
  2
  3creation {ANY}
  4	make
  5
  6feature {ANY}
  7	lower_level: INTEGER is
  8			-- The actual lowest level number.
  9		do
 10			Result := level_list.lower
 11		end
 12
 13	upper_level: INTEGER is
 14			-- The actual upper most level number.
 15		do
 16			Result := level_list.upper
 17		end
 18
 19	hour_price: REAL
 20			-- The day time price to pay per hour.
 21
 22	clock: DATE
 23			-- The parking `clock'.
 24
 25	occupied_slot_count: INTEGER is
 26			-- Total number of cars inside the parking.
 27		local
 28			i: INTEGER
 29		do
 30			from
 31				i := lower_level
 32			until
 33				i > upper_level
 34			loop
 35				Result := Result + level_occupied_slot_count(i)
 36				i := i + 1
 37			end
 38		end
 39
 40	level_occupied_slot_count (level_number: INTEGER): INTEGER is
 41			-- Total number of cars in the given `level_number'.
 42		require
 43			level_number.in_range(lower_level, upper_level)
 44		do
 45			Result := level_list.item(level_number).occupied_slot_count
 46		ensure
 47			Result >= 0
 48		end
 49
 50feature {ANY} -- Modifications:
 51	arrival: INTEGER is
 52			-- Arrival of a new car. The `Result' is the number of the new car or 0 when the parking is full.
 53		local
 54			i: INTEGER; car: CAR
 55		do
 56			from
 57				i := lower_level
 58			until
 59				i > upper_level or else not level_list.item(i).is_full
 60			loop
 61				i := i + 1
 62			end
 63			if i > upper_level or else level_list.item(i).is_full then
 64				Result := 0
 65			else
 66				last_car_number := last_car_number + 1
 67				create car.make(last_car_number, clock.twin)
 68				level_list.item(i).arrival(car)
 69				Result := last_car_number
 70			end
 71		ensure
 72			Result >= 0
 73		end
 74
 75	departure (car: INTEGER): REAL is
 76			-- Gives the price to pay or -1 when cannot be found in the parking.
 77		require
 78			car > 0
 79		local
 80			i: INTEGER; stop: BOOLEAN; c: like clock
 81		do
 82			from
 83				i := lower_level
 84				stop := level_list.count <= 0
 85				Result := -1
 86				c := clock.twin
 87			until
 88				stop
 89			loop
 90				Result := level_list.item(i).departure(car, c, hour_price)
 91				i := i + 1
 92				stop := Result >= 0 or i > upper_level
 93			end
 94		end
 95
 96	add_time (incr: INTEGER) is
 97		do
 98			clock.add_time(incr)
 99		end
100
101	set_hour_price (hp: REAL) is
102		require
103			hp >= 0
104		do
105			hour_price := hp
106		ensure
107			hour_price = hp
108		end
109
110feature {}
111	default_hour_price: REAL is 1.50
112
113	make (ll: like level_list) is
114		require
115			ll /= Void
116		do
117			sedb_breakpoint
118			create clock.make(0, 360)
119			hour_price := default_hour_price
120			level_list := ll
121		ensure
122			hour_price = default_hour_price
123			level_list = ll
124			last_car_number = 0
125		end
126
127	level_list: ARRAY[LEVEL]
128
129	last_car_number: INTEGER
130			-- Used to give different numbers for cars.
131
132invariant
133	valid_price: hour_price >= 0
134
135	clock /= Void
136
137	last_car_number >= 0
138
139	level_list /= Void
140
141end -- class PARKING