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Java
OOP GUIDE / WORK
RANGEDWEAPON CLASS
Topics
- Inheritance
- Using protected instead of
private
- Overriding methods
- Object arrays
TASK –
PART 1 – CONSIDER THE WEAPON CLASS
Start
by copying the following Weapon class to your IDE. Note that there is another exercise where
you can create this class if you are interested in doing so.
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public class
Weapon
{
private String
name;
private int lowDamage;
private int highDamage;
private int damageBonus;
public Weapon(String name, int ld, int hd, int db)
{
this.name = name;
lowDamage = ld;
highDamage = hd;
damageBonus = db;
}
public String
getName()
{
return name;
}
public int getLowDamage()
{
return lowDamage;
}
public int getHighDamage()
{
return highDamage;
}
public int getDamageBonus()
{
return damageBonus;
}
public int getDamageAmount()
{
int dif = highDamage - lowDamage;
int dmg = lowDamage + (int)(Math.random() *
(dif + 1)) + damageBonus;
return dmg;
}
public String
toString()
{
return getDescriptiveName() + "(" + lowDamage + "-" + highDamage + ")
+ " + damageBonus;
}
public void enchantWeapon()
{
damageBonus++;
}
public void curseWeapon()
{
damageBonus--;
}
public String
getDescriptiveName()
{
if (damageBonus <= -2)
return "Cursed
" + name;
else if (damageBonus >= 2)
return name + "
of Power";
else
return name;
}
}
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TASK –
PART 2 – PROBLEM WITH THE WEAPON CLASS
Our Weapon
class works well for almost any kind of video game weapon with one exception
– ranged weapons such as Bows and Slingshots.
Ranged weapons do damage that is based on the weapon itself as well as
on the projectile that it will use.
For example, a bow with an arrow will do less damage than a bow with a silver
arrow! (At least, this is what I’ve
learned from Zelda!)
So we want to
create a RangedWeapon class that will use
Projectile class objects. Let’s start
with the Projectile class.
TASK –
PART 3 – A PROJECTILE CLASS
You
will create a Projectile class with the following specifications:
- It has two private instance
variables
- String name (to contain the projectile name
such as “arrow”)
- int damageIncrease (the amount of damage the
projectile adds to the base weapon’s damage)
- It has a constructor with two
parameters, one for each instance variable.
- It has the following instance
methods:
o A get method for name.
o A get method for damageIncrease.
o A toString method of the form Arrow(+1)
where Arrow is the name and 1 is the value of damageIncrease.
Note:
To keep things simple, Projectiles will not have a descriptive name. So a Silver Arrow that does +3 damage increase
is still just named a silver arrow.
TASK –
PART 4 – A RANGEDWEAPON CLASS (USING INHERITANCE)
You
will now create a RangedWeapon class with the
following specifications:
- It will extend the Weapon class.
- It will need to have access to
the Weapon class’ instance variables so you need to change all of them
from private to protected.
- It contains only one instance
variable (instance object):
- Projectile proj
(the projectile that the ranged weapon will be using)
- It has a constructor with 5
parameters, four of which are to be passed to the super constructor and
one for the projectile.
- It has another constructor with 6
parameters, four of which are to be passed to the super
constructor. The other two are a
String and a damageIncrease value that can be
used to construct our own Projectile object.
- It has the following instance
methods:
- getProjectileName (returns the name of the
projectile)
- getProjectileDamageIncrease (return the projectile’s damage
increase)
- setProjectile(Projectile p) (sets a new type
of projectile)
- setProjectile(String pname,
int pdi) (creates a Projectile object and
sets it as the instance variable)
- It also has the following methods
that override methods from Weapon (use @Override):
- getName (returns a combination of the
Weapon’s name and Projectile name (Example: Bow & Arrow)
- getDescriptiveName (returns the Weapon’s
descriptive name and the Projectiles’ name (Example: Bow of Power &
Arrow)
- getLowDamage (returns the Weapon’s lowDamage added to the Projectile’s damage
increase)
- getHighDamage (returns the Weapon’s highDamage added to the Projectile’s damage increase.
- getDamageAmount (returns a random value between
getLowDamage() and getHighDamage()
added up with the damageBonus of the Weapon.
- toString (returns a String such as Sling of Power & Stone (4-6) + 2).
TASK –
PART 5 – TESTING OUR CLASSES
In a tester
class, create the following objects:
- Create a sword weapon that does 3-5 damage (zero
bonus damage).
- Output the sword to screen.
- Enchant the sword weapon twice.
- Output the sword to screen.
- Create a dart projectile that does +1 damage
increase.
- Output the dart to screen.
- Create a seed projectile that does 0 damage
increase. (Only to be used when
desperate.)
- Output the seed to screen.
- Create a blowpipe ranged weapon. The blowpipe itself does 2-3 damage
with no bonus damage. Set its projectile
type to a dart.
- Output the blowpipe to screen.
- Enchant the blowpipe twice.
- Output the blowpipe to screen.
- Let’s pretend you ran out of darts. Change the blowpipe’s projectile type
to seed.
- Output the blowpipe to screen.
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