chore: modify some methods

src/main/java/minevalley/core/api/gui/InventoryGui.java

@@ -19,9 +19,9 @@
 public interface InventoryGui {
 
     /**
-     * Gets a copy of the underlying inventory of this GUI.
+     * Gets the underlying inventory of this GUI.
      *
-     * @return a copy of the underlying inventory of this GUI
+     * @return the underlying inventory of this GUI
      */
     @Nonnull
     @Contract(pure = true)
@@ -180,14 +180,14 @@ default InventoryGui setItem(@Nonnegative int slot, @Nonnull InterfaceItem item,
     InventoryGui onClickSlot(@Nonnegative int slot, @Nonnull BiConsumer<OnlineUser, InventoryClickEvent> onClick) throws IllegalArgumentException;
 
     /**
-     * Adds a callback to be called when this GUI is closed.
+     * Removes the callback for the specified slot.
      *
-     * @param callback the callback to call
+     * @param slot the slot to remove the callback for
      * @return this GUI
+     * @throws IllegalArgumentException if the slot is out of bounds
      */
     @Nonnull
-    @Contract("_ -> this")
-    InventoryGui onClose(@Nullable Consumer<OnlineUser> callback);
+    InventoryGui removeSlotCallback(@Nonnegative int slot) throws IllegalArgumentException;
 
     /**
      * Adds a callback to be called when this GUI is closed.
@@ -197,7 +197,7 @@ default InventoryGui setItem(@Nonnegative int slot, @Nonnull InterfaceItem item,
      */
     @Nonnull
     @Contract("_ -> this")
-    InventoryGui onClose(@Nullable BiConsumer<OnlineUser, Inventory> callback);
+    InventoryGui onClose(@Nullable Consumer<OnlineUser> callback);
 
     /**
      * Adds a callback to be called when the close button is clicked.
@@ -235,17 +235,14 @@ default InventoryGui setItem(@Nonnegative int slot, @Nonnull InterfaceItem item,
 
     /**
      * Updates the title of this GUI.
-     * This will send a packet to all viewers to update the title.
-     * <p>
-     * <b>Note:</b> calling this method only updates the title for users that already opened this GUI. If you want to update the title for upcoming users, set the {@code updateInventory} parameter to true.
      *
-     * @param title           the new title
-     * @param updateInventory whether to update the inventory
+     * @param title the new title
      * @return this GUI
      * @throws IllegalArgumentException if the title is null
      */
+    @Nonnull
     @Contract(pure = true)
-    InventoryGui updateTitle(@Nonnull Component title, boolean updateInventory) throws IllegalArgumentException;
+    InventoryGui updateTitle(@Nonnull Component title) throws IllegalArgumentException;
 
     /**
      * Opens this GUI for the specified player.

src/main/java/minevalley/core/api/gui/MultiPageGui.java

@@ -79,6 +79,7 @@ MultiPageGui setPageDependantItem(@Nonnegative int slot, @Nonnull Function<Integ
      * @return the inventory of the specified page
      * @throws IllegalArgumentException if the page is out of bounds
      */
+    @Nonnull
     Inventory getInventory(@Nonnegative int page) throws IllegalArgumentException;
 
     /**
@@ -111,8 +112,7 @@ MultiPageGui setPageDependantItem(@Nonnegative int slot, @Nonnull Function<Integ
      * @return a copy of the underlying inventory of this GUI
      */
     @Override
-    @Nonnull
-    default Inventory getInventory() {
+    default @Nonnull Inventory getInventory() {
         return getInventory(0);
     }
 
@@ -124,8 +124,8 @@ default Inventory getInventory() {
      * @return nothing
      */
     @Override
-    @Contract("_, _ -> fail")
-    default InventoryGui updateTitle(@Nonnull Component title, boolean updateInventory) {
+    @Contract("_ -> fail")
+    default @Nonnull InventoryGui updateTitle(@Nonnull Component title) {
         throw new UnsupportedOperationException("This GUI does not support updating the title.");
     }