Java OOD and code duplication

Question

I started creating a basic roleplaying game, and now I work on the basics. I have a code duplication for creating new characters and for existed character, which is a very bad things. I'll explain my problem - At the beginning a player can choose a Character Class (like fighter) by calling using CharacterCreator . I have a Character class that describes all the information regarding the character. I also have an abstract class named CharacterClass that describes specific attributes and other stuff of character classes (like Fighter, not java class). CharacterClass has some subclasses (like Fighter , Mage etc.). The code works, but has a bad design.

How can I get rid of the code duplication of Character and CharacterClass ? Should I change the design?

public class Game {
    public static void main(String[] args) {
        Character hero =  CharacterCreator.CharacterCreator();
    }
}


public class CharacterCreator {

    public static Character CharacterCreator() {
        System.out.println("Choose a character: ");
        System.out.println("1. Fighter");
        System.out.println("2. Rogue");
        System.out.println("3. Mage");
        System.out.println("4. Cleric");


        Scanner sc = new Scanner(System.in);
        int scan = sc.nextInt();
        String choice = getCharacterClass(scan);

        System.out.println("Choose Name:");
        Scanner nameIn = new Scanner(System.in);
        String name = nameIn.next();

        CharacterClass chosenClass = null;
        Character hero = null;

        switch (choice){
        case "Fighter":
            chosenClass = new Fighter();
            break;
        case "Rogue":
            chosenClass = new Rogue();
            break;
        case "Mage":
            chosenClass = new Mage();
            break;
        case "Cleric":
            chosenClass = new Cleric();
            break;
        }

        try {
            hero = new Character(name, chosenClass);
            System.out.println("A hero has been created");
            hero.displayCharacter();
        } catch (Exception e){
            System.out.println("There was a problem assigning a character class");
        }

        return hero;

    }

    public static String getCharacterClass(int scan){

        String classIn;

        switch (scan) {
        case 1:
            classIn = "Fighter";
            break;
        case 2:
            classIn = "Rogue";
            break;
        case 3:
            classIn = "Mage";
            break;
        case 4:
            classIn = "Cleric";
            break;
        default:
            System.out.println("Enter again");
            classIn = "def";
        }

        return classIn;
    }
}

public class Character {

    private String name;
    private String characterClass;
    private int level;
    private int hp;
    private int currentHp;
    private int armorClass;

    private long xp;
    /*private int BAB; /*Base attack bonus*/

    private int strength;
    private int constitution;
    private int dexterity;
    private int intelligence;
    private int wisdom;
    private int charisma;

    Character(String name, CharacterClass chosenClass){

        this.name = name;
        this.characterClass = chosenClass.getCharacterClass();
        level =  chosenClass.getLevel() ;
        hp = ( chosenClass.getHp() + getModifier( chosenClass.getConstitution() )  );
        currentHp = hp;
        setArmorClass(10 + getModifier( + chosenClass.getDexterity()));
        strength = chosenClass.getStrength();
        constitution = chosenClass.getConstitution();
        dexterity = chosenClass.getDexterity();
        intelligence = chosenClass.getIntelligence();
        wisdom = chosenClass.getWisdom();
        charisma = chosenClass.getCharisma();
        xp = 0;


    }

    void displayCharacter() throws IOException {
        System.out.print("\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n");
        System.out.println("Name: " + getName());
        System.out.println("Class: " + getCharacterClass());
        System.out.println("Level: " + getLevel());
        System.out.println("HP: " + getHp());
        System.out.println("Armor Class: " + getArmorClass());

        System.out.println("***************");
        System.out.println("Attributes: ");
        System.out.println("Strength: " + getStrength());
        System.out.println("Constitution: " + getConstitution());
        System.out.println("Dexterity: " + getDexterity());
        System.out.println("Intelligence: " + getIntelligence());
        System.out.println("Wisdom: " + getWisdom());
        System.out.println("Charisma: " + getCharisma());
        System.out.println("***************");
        System.out.println("XP: " + getXp());

    }

    public int getModifier(int number){
        int mod = (int)((number -10)/2);
        return mod;
    }

    public String getName() { return name; }
    public String getCharacterClass() { return characterClass; }
    public int getLevel() { return level; }
    public int getHp() { return  hp; }
    public int getCurrentHp() { return  currentHp; }
    public int getArmorClass() { return  armorClass; }
    public int getStrength(){ return strength; }
    public int getConstitution(){ return constitution; }
    public int getDexterity(){ return dexterity; }
    public int getIntelligence(){ return intelligence; }
    public int getWisdom(){ return wisdom; }
    public int getCharisma(){ return charisma;}
    public long getXp(){ return xp;}


    protected void setLevel(int lvl){ level = lvl; }
    protected void setHp(int hitPoints){ hp = hitPoints; }
    protected void setCurrentHp(int curHp){ currentHp = curHp; }
    protected void setArmorClass(int ac){ armorClass = ac; }
    protected void setStrength(int str){ strength = str; }
    protected void setConstitution(int con){ constitution = con; }
    protected void setDexterity( int dex) { dexterity = dex; }
    protected void setIntelligence(int intel){ intelligence = intel; }
    protected void setWisdom(int wis){ wisdom = wis; }
    protected void setCharisma(int cha){charisma = cha; }



}

abstract class CharacterClass {

    private String characterClass;
    private int level;
    private int hp;

    private int strength;
    private int constitution;
    private int dexterity;
    private int intelligence;
    private int wisdom;
    private int charisma;

    protected CharacterClass(){

        setCharacterClass("Character Class");
        setLevel(1);
        setHp(10);
        setStrength(10);
        setConstitution(10);
        setDexterity(10);
        setIntelligence(10);
        setWisdom(10);
        setCharisma(10);
    }

    public String getCharacterClass() { return characterClass; }
    public int getLevel() { return level; }
    public int getHp() { return  hp; }
    public int getStrength(){ return strength; }
    public int getConstitution(){ return constitution; }
    public int getDexterity(){ return dexterity; }
    public int getIntelligence(){ return intelligence; }
    public int getWisdom(){ return wisdom; }
    public int getCharisma(){ return charisma; }

    protected void setCharacterClass(String characterClass){ this.characterClass = characterClass; }
    protected void setLevel(int lvl){ level = lvl; }
    protected void setHp(int hitPoints){ hp = hitPoints; }
    protected void setStrength(int str){ strength = str; }
    protected void setConstitution(int con){ constitution = con; }
    protected void setDexterity( int dex) { dexterity = dex; }
    protected void setIntelligence(int intel){ intelligence = intel; }
    protected void setWisdom(int wis){ wisdom = wis; }
    protected void setCharisma(int cha){charisma = cha; }

}


class Fighter extends CharacterClass {

    Fighter(){
        setCharacterClass("Fighter");
        setLevel(1);
        setHp(10);
        setStrength(14);
        setConstitution(16);
        setDexterity(14);
        setIntelligence(10);
        setWisdom(10);
        setCharisma(10);
    }
}

Answer 1

suggestions:

1. CharacterCreator.CharacterCreator(). Method should be verb and describe action, ie createCharacter
2. look ad design pattern Factory. Your Creator is 'Factory'. The method 'createCharacter' should take parameter characterType. That means, that getting info from System.in should be done in class who invoke that method.
3. Add enum for characterClass with mapping to numbers (look to inner map in enum).

Answer 2

Whilst this is not a direct solution to your problem, this should help you in the long run. When it comes to games, especially RPG genre, where you have lots of objects which seem to be similar yet different, inheritance isn't best foundation for design. On top of the example you have, one will also have problems when designing consumable items / weapons / gear / NPC, etc. This means you end up with having duplicate code in many classes simply because using abstract class would mean all subclasses have same behavior, but this is not true.

A better approach in this case is to avoid inheritance and use ECS . This means everything is a type of Entity. In order to add some "functionality" to an entity you would use Component types. For example, items don't have HP property, but say when dropped on the ground, they can be attacked and destroyed. Meaning we need to add a dynamic property to it. We can do that as follows:

entityItem.addComponent(new HPComponent(50));

This will allow other systems like Attack/Damage to "see" that the entity has HP component and can be attacked.

This is just a tiny example of ECS and there's lots more to it. I'd suggest reading more about it, as this will make game development design (for most games) significantly smoother.