oop/assignment5/Question3/Vehicle.java

/*
 * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
 * Date: 2022-04-24
 * Description: This is the abstract Vehicle class.
 */

public abstract class Vehicle implements Movable {
	private int speedLimit;
	private int speed;

	/**
	 * Constructor.
	 *
	 * @param speedLimit the speed limit of the vehicle
	 * @param speed      the speed of the vehicle
	 * @throws BadSpeedSetting if speedLimit or speed is negative. Or if the speed
	 *                         is greater than speed limit.
	 */
	public Vehicle(int speedLimit, int speed) throws BadSpeedSetting {
		if (speedLimit < 0 || speed < 0) {
			throw new BadSpeedSetting("Speed cannot be negative!");
		}
		if (speed > speedLimit) {
			throw new BadSpeedSetting("Speed cannot be greater than speed limit!");
		}
		this.speedLimit = speedLimit;
		this.speed = speed;
	}

	/**
	 * Getter of speed.
	 *
	 * @return the speed of the vehicle
	 */
	public int getSpeed() {
		return speed;
	}

	/**
	 * Accelerate the vehicle.
	 *
	 * @param amount the amount of acceleration.
	 * @throws ExceedSpeedLimit if the speed is greater than speed limit after
	 *                          increased.
	 * @thorws NotEnoughSpeed if the speed is less than 0 after decreased.
	 * @return the new speed of the vehicle
	 */
	public int accelerate(int amount) throws ExceedSpeedLimit, NotEnoughSpeed {
		int newSpeed = speed + amount;
		if (newSpeed > speedLimit) {
			throw new ExceedSpeedLimit(
					String.format("Current speed is %d. Accelerate %d will exceed the speed limit!",
							speed, amount));
		}
		if (newSpeed < 0) {
			throw new NotEnoughSpeed(
					String.format("Current speed is %d, not enough speed to decelerate!", speed));
		}
		speed = newSpeed;
		return speed;
	}

	/**
	 * Whether the vehicle can fly or not.
	 *
	 * @return whether the vehicle can fly.
	 */
	public abstract boolean canFly();

	/**
	 * Test.
	 */
	public static void testVehicle() {
		try {
			Vehicle car;
			try {
				car = new Vehicle(-10, -20) {
					@Override
					public boolean canFly() {
						return false;
					}
				};
			} catch (BadSpeedSetting e) {
				System.out.println(e.getMessage().equals("Speed cannot be negative!"));
			}
			try {
				car = new Vehicle(0, 50) {
					@Override
					public boolean canFly() {
						return false;
					}
				};
			} catch (BadSpeedSetting e) {
				System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
			}
			car = new Vehicle(100, 50) {
				@Override
				public boolean canFly() {
					return false;
				}
			};
			System.out.println(car.getSpeed() == 50);
			System.out.println(car.canFly() == false);
			System.out.println(car.accelerate(10) == 60);
			System.out.println(car.accelerate(10) == 70);
			System.out.println(car.accelerate(10) == 80);
			System.out.println(car.accelerate(10) == 90);
			System.out.println(car.accelerate(10) == 100);
			try {
				System.out.println(car.accelerate(10) == 110);
				System.out.println("Error: ExceedSpeedLimit should be thrown!");
			} catch (ExceedSpeedLimit e) {
				System.out.println(e.getMessage().equals(
						"Current speed is 100. Accelerate 10 will exceed the speed limit!"));
			}
			System.out.println(car.accelerate(-50) == 50);
			System.out.println(car.accelerate(-50) == 0);
			try {
				System.out.println(car.accelerate(-50) == -50);
				System.out.println("Error: NotEnoughSpeed should be thrown!");
			} catch (NotEnoughSpeed e) {
				System.out.println(e.getMessage()
						.equals("Current speed is 0, not enough speed to decelerate!"));
			}

			Vehicle plane;
			try {
				plane = new Vehicle(-10, -20) {
					@Override
					public boolean canFly() {
						return true;
					}
				};
			} catch (BadSpeedSetting e) {
				System.out.println(e.getMessage().equals("Speed cannot be negative!"));
			}
			try {
				plane = new Vehicle(0, 50) {
					@Override
					public boolean canFly() {
						return true;
					}
				};
			} catch (BadSpeedSetting e) {
				System.out.println(e.getMessage().equals("Speed cannot be greater than speed limit!"));
			}
			plane = new Vehicle(100, 50) {
				@Override
				public boolean canFly() {
					return true;
				}
			};
			System.out.println(plane.getSpeed() == 50);
			System.out.println(plane.canFly() == true);
			System.out.println(plane.accelerate(10) == 60);
			System.out.println(plane.accelerate(10) == 70);
			System.out.println(plane.accelerate(10) == 80);
			System.out.println(plane.accelerate(10) == 90);
			System.out.println(plane.accelerate(10) == 100);
			try {
				System.out.println(plane.accelerate(10) == 110);
				System.out.println("Error: ExceedSpeedLimit should be thrown!");
			} catch (ExceedSpeedLimit e) {
				System.out.println(e.getMessage().equals(
						"Current speed is 100. Accelerate 10 will exceed the speed limit!"));
			}
			System.out.println(plane.accelerate(-50) == 50);
			System.out.println(plane.accelerate(-50) == 0);
			try {
				System.out.println(plane.accelerate(-50) == -50);
				System.out.println("Error: NotEnoughSpeed should be thrown!");
			} catch (NotEnoughSpeed e) {
				System.out.println(e.getMessage()
						.equals("Current speed is 0, not enough speed to decelerate!"));
			}
		} catch (Exception e) {
			System.out.println("Error: Uncatched exception!");
		}
	}
}