Gamelogic - variable in another class

[UndersKore]

Hello everyone, I'm still kind of new to programming and I need some help on a project I just started..

How it works:
The 'game' class has three objects: inventory, items and miner
Inventory has 20 slot objects and items has an arraylist which contains item objects
gamelogic.png

Now..
I want the miner object to be able to check the amount of slots which are free in the inventory, but I'm not sure about how to do this
Should I pass the inventory object to each new miner object I create? Or is there another way to do this?
Right now the only arguments which are given to a new miner object are the rock it should mine and the amount of ores it has to mine, for example:
Miner miner = new Miner(Ore.COAL, 20); would mine 20 coal ores.

LONG STORY SHORT:
I need the best way to let the miner object get the 'slotsOccupied' variable from the inventory object

What I have so far:

Game

public class Game {
 
    private Items items;
    private Inventory inventory;
 
    public Game() {
        items = new Items();
        for (Rock rock : Rock.values())
            items.addItem(rock.toString(), rock.toString() + " ore", rock.getPrice());
        items.addItem("Pickaxe", "It's a pickaxe", 1000);
 
        inventory = new Inventory();
 
        mineStuff();
 
    }
 
    public void mineStuff() {
        Miner miner = new Miner(Rock.TIN, 20);
    }
 
}

Items

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
 
public class Items {
 
    List<Item> items = new ArrayList<Item>();
 
    public void addItem(String name, String description, int price) {
        items.add(new Item(items.size(), name, description, price));
    }
 
    public void deleteItem(int itemID) {
        items.remove(itemID);
    }
 
    public int getItemID(String name) {
        Iterator<Item> it = items.iterator();
        while (it.hasNext()) {
            Item item = it.next();
            if (item.getName().equalsIgnoreCase(name))
                return item.getItemID();
        }
        return -1;
    }
 
    public String getItemName(int itemID) {
        return items.get(itemID).getName();
    }
 
    public String getItemDescription(int itemID) {
        return items.get(itemID).getDescription();
    }
 
    public int getItemPrice(int itemID) {
        return items.get(itemID).getPrice();
    }
 
}

Item

public class Item {
 
    private int itemID;
    private String name;
    private String description;
    private int price;
 
    public Item(int itemID, String name, String description, int price) {
        this.itemID = itemID;
        this.name = name;
        this.description = description;
        this.price = price;
    }
 
    public int getItemID() {
        return itemID;
    }
 
    public String getName() {
        return name;
    }
 
    public String getDescription() {
        return description;
    }
 
    public int getPrice() {
        return price;
    }
 
}

Inventory

public class Inventory {
 
    public static final int MAX_SLOTS = 20;
    private int slotsOccupied = 0;
    private Slot[] inventory = new Slot[MAX_SLOTS];
 
    public boolean put(Item item, int amount) {
        if (slotsOccupied < MAX_SLOTS) {
            inventory[slotsOccupied++] = new Slot(item, amount);
            return true;
        } else {
            return false;
        }
    }
 
    public Item getItem(int slot) {
        return inventory[slot].getItem();
    }
 
    public int getSlotsOccupied() {
        return slotsOccupied;
    }
 
    @Override
    public String toString() {
        StringBuilder s = new StringBuilder();
        for (int i = 0; i < inventory.length; i++)
            s.append(inventory[i].getItem().getName() + " x " + inventory[i].getAmount() + "\n");
        return s.toString();
    }
}

Slot

public class Slot {
 
    private Item item;
    private int amount;
 
    public Slot(Item item, int amount) {
        this.item = item;
        this.amount = amount;
    }
 
    public void setAmount(int amount) {
        this.amount = amount;
    }
 
    public void setItem(Item item) {
        this.item = item;
    }
 
    public int getAmount() {
        return amount;
    }
 
    public Item getItem() {
        return item;
    }
}

Rock

enum Rock {
 
    TIN(1, 10),
    COPPER(1, 10),
    IRON(5, 15),
    COAL(30, 25),
    MITHRIL(45, 80),
    ADAMANT(60, 120),
    RUNE(85, 200);
 
    private int requiredLevel;
    private int price;
 
    private Rock(int requiredLevel, int price) {
        this.requiredLevel = requiredLevel;
        this.price = price;
    }
 
    public int getRequiredLevel() {
        return requiredLevel;
    }
 
    public int getPrice() {
        return price;
    }
 
    @Override
    public String toString() {
        return name().toLowerCase();
    }
}

Miner

public class Miner {
 
    private Rock rock;
    private int amount;
 
    public Miner(Rock rock, int amount) {
        if (amount < Inventory.MAX_SLOTS) { //here I need the slotsOccupied for!
            this.rock = rock;
            this.amount = amount;
        }
    }
 
   /* public void start() {
        try {
 
        } catch (InterruptedException ex) {
            System.out.println(ex.getMessage());
        }
    } */
 
}

If you have any questions, please ask!

Thank you for your time (:

[UndersKore]

I solved it myself, I hope it's a good way.. :p

Miner

public class Miner {
 
    private Inventory inventory;
    private Items items;
 
    public Miner(Inventory inventory, Items items) {
        this.inventory = inventory;
        this.items = items;
    }
 
    public boolean mine(Rock rock, int amount) {
        if (inventory.getSlotsOccupied() + amount > inventory.MAX_SLOTS)
            return false;
        startMining(rock, amount);
        return true;
    }
 
    public void startMining(Rock rock, int amount) {
        try {
            for (int i = 0; i < amount; i++) {
                Thread.sleep(1000);
                inventory.put(items.getItem(items.getItemID(rock.toString())), amount);
            }
        } catch (InterruptedException ex) {
            System.out.println(ex.getMessage());
        }
    }
 
}

Game

public class Game {
 
    private Items items;
    private Inventory inventory;
    private Miner miner;
 
    public Game() {
        items = new Items();
        for (Rock rock : Rock.values())
            items.addItem(rock.toString(), rock.toString() + " ore", rock.getPrice());
        items.addItem("Pickaxe", "It's a pickaxe", 1000);
 
        inventory = new Inventory();
 
        Miner miner = new Miner(inventory, items);
 
        mineStuff();
 
    }
 
    public void mineStuff() {
        miner.startMining(Rock.TIN, 15);
        miner.startMining(Rock.RUNE, 2);
        miner.startMining(Rock.COAL, 2);
    }
 
}

Items

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
 
public class Items {
 
    List<Item> items = new ArrayList<Item>();
 
    public void addItem(String name, String description, int price) {
        items.add(new Item(items.size(), name, description, price));
    }
 
    public void deleteItem(int itemID) {
        items.remove(itemID);
    }
 
    public int getItemID(String name) {
        Iterator<Item> it = items.iterator();
        while (it.hasNext()) {
            Item item = it.next();
            if (item.getName().equalsIgnoreCase(name))
                return item.getItemID();
        }
        return -1;
    }
 
    public String getItemName(int itemID) {
        return items.get(itemID).getName();
    }
 
    public String getItemDescription(int itemID) {
        return items.get(itemID).getDescription();
    }
 
    public int getItemPrice(int itemID) {
        return items.get(itemID).getPrice();
    }
 
    public Item getItem(int itemID) {
        return items.get(itemID);
    }
 
}