Java

OOP GUIDE / WORK

BOTTLE CLASS

Topics

• Advanced class design
• Advanced method design
• Encapsulation

TASK – PART 1 – BOTTLE CLASS

Design the Bottle class with the following specifications:

INSTANCE VARIABLES

• private String colour – The colour of the bottle.
• private int maxVolume – The volume of the bottle in mL.
• private int filledVolume – Amount of liquid in the bottle in mL.
• private String content – The type of liquid in the bottle. Possible examples include “” (when empty), “water”, “milk”, “pop & water”, “coffee & tea & water”.

CONSTRUCTOR

• One constructor that gets the colour and bottle’s volume. New bottles always start off empty.

METHODS – PART 1 – BASIC GET METHODS

• getColour – Returns the colour as a String
• getMaxVolume – Returns the bottle’s volume
• getFilledVolume – Returns the amount of liquid in the bottle
• getContent – Returns the type of liquid in the bottle. However, if the bottle is empty, it returns the String “nothing”.
  
  

METHODS – PART 2 – MORE METHODS

• getRemainingVolume() – Returns the amount of room left in the bottle (in mL).
• getPercentFull – Returns the percentage (as a decimal between 0.0 and 1.0) of the bottle that is full. So, 0.55 means that the bottle is 55% full.
• getPercentEmpty – Returns the percentage (as a decimal between 0.0 and 1.0) of the bottle that is empty.
• isEmpty() – Returns true if the bottle is empty and false otherwise.
• isFull() – Returns true if the bottle is full and false otherwise.
• contains(String liquid) – Returns true if the content of the bottle already includes liquid. You can make use of the String class’ contains method here for an easy solution.

METHODS – PART 3 – TOSTRING

• Returns a String representing the bottle. See below for two examples:

Green bottle (1000mL) contains water (20.0% full).

Blue bottle (500mL) contains nothing (0.0% full).

METHODS – PART 4 – MORE METHODS

• pourOut() – Sets the bottle to empty.
• pourOut(int vol) – Removes vol from the filledVolume. You need to consider what happens if the bottle is empty after this action. Also, if the value of vol is greater than filledVolume, simply empty the bottle and output:
  
  Error. The bottle doesn't have that much in it. Bottle emptied.
  
  

METHODS – PART 5 – ADDLIQUID() METHOD

• addLiquid(String newLiquid, int volumeToAdd) – If the bottle has room in it, it adds the newLiquid to it. If the bottle was already full, you should display the msg:

Overflow - bottle is already full.

If there is not enough room to place all the liquid in, you should fill the bottle and display:

Overflow. Bottle is now full.

Note: The content of the liquid starts off as “”. If you add “water” the content is then “water”. If you add “milk”, the content is then “water & milk”. If you add “water” again, the content remains “water & milk”. If you add “tea”, the content becomes “water & milk & tea”.

TASK – PART 2 – BOTTLE CLASS TESTER

Use the following BottleTester class to test your Bottle class:

public class BottleTester

{

public static void main(String[] args)

{

Bottle b = new Bottle(1000, "Green");

System.out.println(b);

b.addLiquid("water", 200);

System.out.println(b);

b.addLiquid("water", 300);

System.out.println(b);

b.addLiquid("milk", 200);

System.out.println(b);

b.addLiquid("milk", 100);

System.out.println(b);

b.pourOut(200);

System.out.println(b);

b.pourOut();

System.out.println(b);

}

}

It should output the following:

Green bottle (1000mL) contains nothing (0.0% full).

Green bottle (1000mL) contains water (20.0% full).

Green bottle (1000mL) contains water (50.0% full).

Green bottle (1000mL) contains water & milk (70.0% full).

Green bottle (1000mL) contains water & milk (80.0% full).

Green bottle (1000mL) contains water & milk (60.0% full).

Green bottle (1000mL) contains nothing (0.0% full).

TASK – PART 3 – BOTTLE CLASS TESTER 2

Use the following BottleTester2 class to test your Bottle class:

public class BottleTester2

{

public static void main(String[] args)

{

Bottle bot = new Bottle(500, "Red");

System.out.println(bot);

bot.addLiquid("coffee", 250);

System.out.println(bot);

bot.addLiquid("tea", 300);

System.out.println(bot);

bot.pourOut(400);

System.out.println(bot);

bot.addLiquid("pop", 400);

System.out.println(bot);

bot.addLiquid("juice", 100);

System.out.println(bot);

}

}

It should output the following:

Red bottle (500mL) contains nothing (0.0% full).

Red bottle (500mL) contains coffee (50.0% full).

Overflow. Bottle is now full.

Red bottle (500mL) contains coffee & tea (100.0% full).

Red bottle (500mL) contains coffee & tea (20.0% full).

Red bottle (500mL) contains coffee & tea & pop (100.0% full).

Overflow - bottle is already full.

Red bottle (500mL) contains coffee & tea & pop (100.0% full).