/**
 * Describing all glasses of water in the known world
 */
public class GlassOfWater 
{
	private final Material material;
	private final Weight weight;
	private int capacity;
	
	/**
	 * When creating a new glass of water you have to say what material, how
	 * much it weights and how much water it can hold.
	 * 
	 * Pretty much like "Simon says"
	 * 
	 * @param material the material of the glass
	 * @param weight its weight
	 * @param capacity how much water can it hold
	 */
	public GlassOfWater(Material material, Weight weight, int capacity) 
	{
		this.material = material;
		this.weight = weight;
		this.capacity = capacity;
	}

	/**
	 * @return true if you can smash it, is it made of glass?
	 */
	public boolean smash() {
	return this.material.equals(Material.GLASS);
	}
	
	/**
	 * @return true if you can lift it, is it light?
	 */
	public boolean lift() {
	return this.weight.equals(Weight.LIGHT);
	}
	
	/**
	 * Drink responsibly
	 *  
	 * @param amount how much do you want to drink
	 * @return what's left.
	 */
	public int drink(int amount){
	return this.capacity -= amount;
	}
}

/**
 * Let's prove our theory that you can indeed lift/smash and drink from a glass 
 * of water
 */
public class GlassOfWaterTest 
{
	@Test
	public void test() throws Exception 
	{
		/**
		 * Here is your glass of water object.
		 */
		GlassOfWater aGlassOfWater = new GlassOfWater(Material.PLASTIC, Weight.HEAVY, 330);
		
		/**
		 * Let's drink some, water level drops
		 */
		int remainingWater = aGlassOfWater.drink(330);
		
		Assert.assertFalse( aGlassOfWater.lift() );
		Assert.assertFalse( aGlassOfWater.smash() );
		Assert.assertEquals( 0, remainingWater );
	}
}