Remove BossBar from the Player class, BossBar#addViewer should be used instead

src/main/java/net/minestom/server/advancements/AdvancementTab.java

@@ -18,6 +18,8 @@ public class AdvancementTab implements Viewable {
 
     private Set<Player> viewers = new HashSet<>();
 
+    private AdvancementRoot root;
+
     // Advancement -> its parent
     private Map<Advancement, Advancement> advancementMap = new HashMap<>();
 
@@ -27,13 +29,24 @@ public class AdvancementTab implements Viewable {
     // will never change (since the root identifier is always the same)
     protected ByteBuf removeBuffer;
 
-    protected AdvancementTab(String rootIdentifier, Advancement root) {
+    protected AdvancementTab(String rootIdentifier, AdvancementRoot root) {
+        this.root = root;
+
         cacheAdvancement(rootIdentifier, root, null);
 
         final AdvancementsPacket removePacket = AdvancementUtils.getRemovePacket(new String[]{rootIdentifier});
         this.removeBuffer = PacketUtils.writePacket(removePacket);
     }
 
+    /**
+     * Get the root advancement of this tab
+     *
+     * @return the root advancement
+     */
+    public AdvancementRoot getRoot() {
+        return root;
+    }
+
     /**
      * Create and add an advancement into this tab
      *

src/main/java/net/minestom/server/bossbar/BossBar.java

@@ -34,17 +34,19 @@ public class BossBar implements Viewable {
 
     @Override
     public boolean addViewer(Player player) {
-        boolean result = this.viewers.add(player);
-        player.refreshAddBossbar(this);
-        addToPlayer(player);
+        final boolean result = this.viewers.add(player);
+        if (result) {
+            addToPlayer(player);
+        }
         return result;
     }
 
     @Override
     public boolean removeViewer(Player player) {
-        boolean result = this.viewers.remove(player);
-        player.refreshRemoveBossbar(this);
-        removeToPlayer(player);
+        final boolean result = this.viewers.remove(player);
+        if (result) {
+            removeToPlayer(player);
+        }
         return result;
     }
 
@@ -139,7 +141,6 @@ public class BossBar implements Viewable {
         bossBarPacket.uuid = uuid;
         bossBarPacket.action = BossBarPacket.Action.REMOVE;
         sendPacketToViewers(bossBarPacket);
-        getViewers().forEach(player -> player.refreshRemoveBossbar(this));
     }
 
     private void addToPlayer(Player player) {

src/main/java/net/minestom/server/entity/Player.java

@@ -2,7 +2,6 @@ package net.minestom.server.entity;
 
 import net.minestom.server.MinecraftServer;
 import net.minestom.server.attribute.Attribute;
-import net.minestom.server.bossbar.BossBar;
 import net.minestom.server.chat.ChatParser;
 import net.minestom.server.chat.ColoredText;
 import net.minestom.server.chat.RichMessage;
@@ -108,7 +107,6 @@ public class Player extends LivingEntity implements CommandSender {
     private byte targetLastStage;
     private int blockBreakTime;
 
-    private Set<BossBar> bossBars = new CopyOnWriteArraySet<>();
     private Team team;
     private BelowNameScoreboard belowNameScoreboard;
 
@@ -490,7 +488,6 @@ public class Player extends LivingEntity implements CommandSender {
     public void remove() {
         super.remove();
         this.packets.clear();
-        clearBossBars();
         if (getOpenInventory() != null)
             getOpenInventory().removeViewer(this);
         this.viewableEntities.forEach(entity -> entity.removeViewer(this));
@@ -1411,13 +1408,6 @@ public class Player extends LivingEntity implements CommandSender {
         return targetCustomBlock;
     }
 
-    /**
-     * @return an unmodifiable {@link Set} containing all the current player viewable boss bars
-     */
-    public Set<BossBar> getBossBars() {
-        return Collections.unmodifiableSet(bossBars);
-    }
-
     /**
      * Get the player open inventory
      *
@@ -1527,13 +1517,6 @@ public class Player extends LivingEntity implements CommandSender {
         return Collections.unmodifiableSet(viewableChunks);
     }
 
-    /**
-     * Remove all the boss bars that the player has
-     */
-    public void clearBossBars() {
-        this.bossBars.forEach(bossBar -> bossBar.removeViewer(this));
-    }
-
     /**
      * Send a {@link UpdateViewPositionPacket}  to the player
      *
@@ -1891,26 +1874,6 @@ public class Player extends LivingEntity implements CommandSender {
         }
     }
 
-    /**
-     * Used internally to add Bossbar in the {@link #getBossBars()} set
-     * You probably want to use {@link BossBar#addViewer(Player)}
-     *
-     * @param bossBar the bossbar to add internally
-     */
-    public void refreshAddBossbar(BossBar bossBar) {
-        this.bossBars.add(bossBar);
-    }
-
-    /**
-     * Used internally to remove Bossbar from the {@link #getBossBars()} set
-     * You probably want to use {@link BossBar#removeViewer(Player)}
-     *
-     * @param bossBar the bossbar to remove internally
-     */
-    public void refreshRemoveBossbar(BossBar bossBar) {
-        this.bossBars.remove(bossBar);
-    }
-
     public void refreshVehicleSteer(float sideways, float forward, boolean jump, boolean unmount) {
         this.vehicleInformation.refresh(sideways, forward, jump, unmount);
     }