Add method to check if inv has enough space to fit given items (#36)

src/main/java/pro/cloudnode/smp/bankaccounts/BankAccounts.java

@@ -10,6 +10,9 @@
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.PluginCommand;
 import org.bukkit.event.Listener;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryHolder;
+import org.bukkit.inventory.ItemStack;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -323,6 +326,32 @@ public static Optional<String> checkForUpdates() {
         return Optional.empty();
     }
 
+    /**
+     * Check if an inventory can fit items
+     *
+     * @param inventory The inventory that you want to hold the items
+     * @param items The items to check if they can fit in the inventory
+     * @return A HashMap containing items that didn't fit.
+     */
+    public static @NotNull HashMap<@NotNull Integer, @NotNull ItemStack> canFit(final @NotNull Inventory inventory, final @NotNull ItemStack... items) {
+        final @NotNull Inventory inv = getInstance().getServer().createInventory(null, inventory.getSize());
+        inv.setContents(inventory.getContents());
+        final @NotNull HashMap<@NotNull Integer, @NotNull ItemStack> didNotFit = inv.addItem(items);
+        inv.close();
+        return didNotFit;
+    }
+
+    /**
+     * Check if entity's inventory can fit items
+     *
+     * @param entity The entity that you want to hold the items
+     * @param items The items to check if they can fit in the inventory
+     * @return A HashMap containing items that didn't fit.
+     */
+    public static @NotNull HashMap<@NotNull Integer, @NotNull ItemStack> canFit(final @NotNull InventoryHolder entity, final @NotNull ItemStack... items) {
+        return canFit(entity.getInventory(), items);
+    }
+
     public static final class Key {
         public final static @NotNull NamespacedKey INSTRUMENT_ACCOUNT = namespacedKey("instrument-account");
         public final static @NotNull NamespacedKey POS_OWNER_GUI = namespacedKey("pos-owner-gui");