Potential packet fix

api/src/main/java/net/jitse/npclib/api/NPC.java

@@ -20,15 +20,13 @@ import java.util.UUID;
 public interface NPC {
 
     /**
-     *
      * @param player
      * @return unique hologram for that user
      */
     Hologram getPlayerHologram(Player player);
 
     /**
-     *
-     * @param uniqueLines The text that the targetPlayer will see
+     * @param uniqueLines  The text that the targetPlayer will see
      * @param targetPlayer The target player
      * @return object instance
      * @author Gatt
@@ -36,17 +34,15 @@ public interface NPC {
     NPC setPlayerLines(List<String> uniqueLines, Player targetPlayer);
 
     /**
-     *
-     * @param uniqueLines The text that the targetPlayer will see
+     * @param uniqueLines  The text that the targetPlayer will see
      * @param targetPlayer The target player
-     * @param update whether or not to send the update packets
+     * @param update       whether or not to send the update packets
      * @return object instance
      * @author Gatt
      */
     NPC setPlayerLines(List<String> uniqueLines, Player targetPlayer, boolean update);
 
     /**
-     *
      * @param targetPlayer The target player
      * @return the lines that the targetPlayer will see, if null; default lines.
      */
@@ -91,6 +87,13 @@ public interface NPC {
      */
     NPC create();
 
+    /**
+     * Check whether the NPCs packets have already been generated.
+     *
+     * @return Whether NPC#create has been called yet.
+     */
+    boolean isCreated();
+
     /**
      * Get the ID of the NPC.
      *

api/src/main/java/net/jitse/npclib/internal/NPCBase.java

@@ -41,6 +41,7 @@ public abstract class NPCBase implements NPC, NPCPacketHandler {
     protected UUID uuid = new UUID(new Random().nextLong(), 0);
     protected String name = uuid.toString().replace("-", "").substring(0, 10);
     protected GameProfile gameProfile = new GameProfile(uuid, name);
+    protected boolean created = false;
 
     protected NPCLib instance;
     protected List<String> text;
@@ -177,7 +178,7 @@ public abstract class NPCBase implements NPC, NPCPacketHandler {
 
     @Override
     public boolean isShown(Player player) {
-        if (player == null) return false;
+        Objects.requireNonNull(player, "Player object cannot be null");
         return shown.contains(player.getUniqueId()) && !autoHidden.contains(player.getUniqueId());
     }
 
@@ -190,9 +191,15 @@ public abstract class NPCBase implements NPC, NPCPacketHandler {
     @Override
     public NPC create() {
         createPackets();
+        this.created = true;
         return this;
     }
 
+    @Override
+    public boolean isCreated() {
+        return created;
+    }
+
     public void onLogout(Player player) {
         getAutoHidden().remove(player.getUniqueId());
         getShown().remove(player.getUniqueId()); // Don't need to use NPC#hide since the entity is not registered in the NMS server.

api/src/main/java/net/jitse/npclib/listeners/PacketListener.java

@@ -49,7 +49,7 @@ public class PacketListener {
     }
 
     private boolean handleInteractPacket(Player player, Object packet) {
-        if (!packetPlayInUseEntityClazz.isInstance(packet))
+        if (!packetPlayInUseEntityClazz.isInstance(packet) || player == null)
             return true; // We aren't handling the packet.
 
         NPCBase npc = null;
@@ -62,7 +62,7 @@ public class PacketListener {
         // ~ Kneesnap, 9 / 20 / 2019.
 
         for (NPCBase testNPC : NPCManager.getAllNPCs()) {
-            if (testNPC.isShown(player) && testNPC.getEntityId() == packetEntityId) {
+            if (testNPC.isCreated() && testNPC.isShown(player) && testNPC.getEntityId() == packetEntityId) {
                 npc = testNPC;
                 break;
             }

nms/v1_16_R1/src/main/java/net/jitse/npclib/nms/v1_16_R1/NPC_v1_16_R1.java

@@ -36,17 +36,17 @@ public class NPC_v1_16_R1 extends NPCBase {
     public NPC_v1_16_R1(NPCLib instance, List<String> lines) {
         super(instance, lines);
     }
+
     @Override
     public Hologram getPlayerHologram(Player player) {
         Hologram holo = super.getPlayerHologram(player);
-        if (holo == null){
+        if (holo == null) {
             holo = new Hologram(MinecraftVersion.V1_16_R1, location.clone().add(0, 0.5, 0), getPlayerLines(player));
         }
         super.textDisplayHolograms.put(player.getUniqueId(), holo);
         return holo;
     }
 
-
     @Override
     public void createPackets() {
         Bukkit.getOnlinePlayers().forEach(this::createPackets);