carsalessystem.java

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	public void componentHidden(ComponentEvent ev) {}

	public void componentMoved(ComponentEvent ev) {}

	/**
	 * receives events when JFrame is resized and ensures the application doesn't get resized
	 * below a minimum size which could cause display problems in the application
	 *
	 * @param ev ComponentEvent object
	 */
	public void componentResized(ComponentEvent ev)
	{
		if (this == ev.getComponent())
		{
			Dimension size = getSize();

			if (size.height < 530)
				size.height = 530;
			if (size.width < 675)
				size.width = 675;

			setSize(size);
		}
	}

	public void componentShown(ComponentEvent ev) {}

	/**
	 * Converts a range string such as "50-100" or "20+" to a double array with minimum and maximum
	 * bounds
	 *
	 * @param s a string containing a valid range. "200", "100-200", "20+" are all examples
	 * of valid ranges
	 * @return array of 2 elements. First element indicating minimum bounds, second element
	 * indicating maximum bounds. A value of -1 for minimum and maximum bounds indicates an error
	 * in converting the parameter to a proper range. A value of -1 for the maximum bounds and
	 * a value > 0 for the minimum bounds indicates the maximum bounds is infinity in theory.
	 * If both bounds are greater than 0, this indicates a valid range a to b, where a and b
	 * can be equal.
	 */
	public static double[] convertToRange(String s)
	{
		String[] parts = s.trim().split("-");
		double[] bounds = new double[2];

		try
		{
			// if true the range is either of the form 'm+' or 'm'
			if (parts.length == 1)
			{
				String c = s.substring(s.length() - 1);

				// if in the form "m+"
				if (c.equals("+"))
				{
					// get lower bounds from the string
					bounds[0] = Double.parseDouble(s.substring(0, s.length() - 1));
					// no upper maximum specified, infinite
					bounds[1] = -1;
				}
				// if true the number is of the form 'm'
				else
				{
					// upper bounds == lower bounds. The range is actually just a single number
					bounds[0] = Double.parseDouble(s);
					bounds[1] = bounds[0];
				}
			}
			// if true, in the form "m-n"
			else if(parts.length == 2)
			{
				bounds[0] = Double.parseDouble(parts[0]);
				bounds[1] = Double.parseDouble(parts[1]);
				if (bounds[0] > bounds[1])
				{
					//incorrect bounds, example, 10-5
					bounds[0] = -1;
					bounds[1] = -1;
				}
			}
		}
		catch (NumberFormatException exp)
		{
			//incorrect bounds format
			bounds[0] = -1;
			bounds[1] = -1;
		}

		return bounds;
	}

	/**
	 * gets the entire list of cars from CarsCollection
	 *
	 * @return array of cars containing individual details
	 */
	public Car[] getAllCars()
	{
		return carCollection.getAllCars();
	}


	/**
	 * checks if the cars have been updated since last program launch
	 *
	 * @return boolean indicating whether the cars have been updated
	 */
	public boolean getCarsUpdated()
	{
		return carsUpdated;
	}

	/**
	 * Retrieves statistics about the car collection
	 *
	 * @param type can be either CARS_COUNT, MANUFACTURERS_COUNT, AVERAGE_PRICE, AVERAGE_DISTANCE or
	 * AVERAGE_AGE
	 * @return a value with the queried statistic returned
	 */
	public double getStatistics(int type)
	{
		double result = 0;

		if (type == CARS_COUNT)
		{
			result	= carCollection.carsCount();
		}
		else if (type == MANUFACTURERS_COUNT)
		{
			result = carCollection.manufacturerCount();
		}
		else if (type == AVERAGE_PRICE)
		{
			result = carCollection.getAveragePrice();
		}
		else if (type == AVERAGE_DISTANCE)
		{
			result = carCollection.getAverageDistance();
		}
		else if (type == AVERAGE_AGE)
		{
			result = carCollection.getAverageAge();
		}

		return result;
	}

	/**
	 * initialize the CarSalesSystem.
	 *
	 * @param args name of binary file to use is the only argument needed
	 */
	public static void main(String[] args)
	{
		CarSalesSystem carSales = new CarSalesSystem("cars.dat");
		carSales.setVisible(true);
	}

	/**
	 * search by age, using the CarsCollection
	 *
	 * @param minAge minimum age of car
	 * @param maxAge maimum age of car
	 * @return array of cars that match the search criteria
	 */
	public Car[] search(int minAge, int maxAge)
	{
		return carCollection.search(minAge, maxAge);
	}

	/**
	 * Search by age using the CarsCollection
	 *
	 * @param minPrice minimum price of car
	 * @param maxPrice maximum price of car
	 * @param minDistance minimum distance travelled by car
	 * @param maxDistance maximum distance travelled by car
	 * @return array of cars that match the search criteria
	 */
	public Car[] search(int minPrice, int maxPrice, double minDistance, double maxDistance)
	{
		return carCollection.search(minPrice, maxPrice,  minDistance, maxDistance);
	}

	/**
	 * call this method to alert the Car Sales System that a car has been added, and also send
	 * messages to all registered car update listeners
	 */
	public void setCarsUpdated()
	{
		carsUpdated = true;

		for (int i = 0; i < registeredListeners.size(); i++)
		{
			Class[] paramType = {CarUpdateEvent.class};
			Object[] param = {new CarUpdateEvent(this)};

			try
			{
				//get a reference to the method which we want to invoke to the listener
				java.lang.reflect.Method callingMethod = registeredListeners.get(i).getClass().getMethod("carsUpdated", paramType);
				//invoke the method with our parameters
				callingMethod.invoke(registeredListeners.get(i), param);
			}
			catch (NoSuchMethodException exp)
			{
				System.out.println("Warning, 'public carsUpdated(CarEvent)' method does not exist in " + registeredListeners.get(i).getClass().getName() + ". You will not receive any car update events");
			}
			catch (IllegalAccessException exp)
			{
				System.out.println("Warning, the 'public carUpdated(CarEvent)' method couldn't be called for unknown reasons, You will not receive any car update events");
			}
			catch (Exception exp){}
		}
	}

	/**
	 * the selected tab in the JTabbedPane has been changed, so change the title bar text
	 *
	 * @param ev ChangeEvent object
	 */
	public void stateChanged(ChangeEvent ev)
	{
		if (ev.getSource() == theTab)
			statusLabel.setText("Current panel: " + theTab.getTitleAt(theTab.getSelectedIndex()));
	}

	/**
	 * converts a vector to a car array
	 *
	 * @param v vector containing array of Car objects only
	 * @return Car array containing car objects from the vector
	 */
	public static Car[] vectorToCar(Vector v)
	{
		Car[] ret = new Car[v.size()];

		for (int i = 0; i < v.size(); i++)
		{
			ret[i] = (Car)v.elementAt(i);
		}

		return ret;
	}

	class WindowCloser extends WindowAdapter
	{
		/**
		 * calls the car sales system's main closing event
		 *
		 * @param ev WindowEvent object
		 */
		public void windowClosing(WindowEvent ev)
		{
			closing();
		}
	}
}