Option to prevent high party level difference

src/main/java/net/Indyuce/mmocore/gui/social/party/EditablePartyView.java

@@ -172,6 +172,13 @@ public class EditablePartyView extends EditableInventory {
                         return;
                     }
 
+                    if (Math.abs(targetData.getLevel() - party.getLevel()) > MMOCore.plugin.configManager.maxPartyLevelDifference) {
+                        MMOCore.plugin.configManager.getSimpleMessage("high-level-difference", "player", target.getName()).send(player);
+                        player.playSound(player.getLocation(), Sound.ENTITY_VILLAGER_NO, 1, 1);
+                        open();
+                        return;
+                    }
+
                     party.sendInvite(playerData, targetData);
                     MMOCore.plugin.configManager.getSimpleMessage("sent-party-invite", "player", target.getName()).send(player);
                     player.playSound(player.getLocation(), Sound.ENTITY_EXPERIENCE_ORB_PICKUP, 1, 1);

src/main/java/net/Indyuce/mmocore/manager/ConfigManager.java

@@ -99,7 +99,6 @@ public class ConfigManager {
         globalSkillCooldown = MMOCore.plugin.getConfig().getLong("global-skill-cooldown") * 50;
         noSkillBoundPlaceholder = getSimpleMessage("no-skill-placeholder").message();
         lootChestsChanceWeight = MMOCore.plugin.getConfig().getDouble("chance-stat-weight.loot-chests");
-        attributesAsClassInfo = MMOCore.plugin.getConfig().getBoolean("attributes-as-class-info");
 
         staminaFull = getColorOrDefault("stamina-whole", ChatColor.GREEN);
         staminaHalf = getColorOrDefault("stamina-half", ChatColor.DARK_GREEN);

src/main/java/net/Indyuce/mmocore/party/provided/Party.java

@@ -9,6 +9,7 @@ import net.Indyuce.mmocore.gui.social.party.EditablePartyView.PartyViewInventory
 import net.Indyuce.mmocore.manager.InventoryManager;
 import net.Indyuce.mmocore.party.AbstractParty;
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 import java.util.function.Consumer;
@@ -25,13 +26,21 @@ public class Party implements AbstractParty {
     /**
      * Owner has to change when previous owner leaves party
      */
+    @NotNull
     private PlayerData owner;
 
+    /**
+     * If the difference between a player level and the party
+     * level is too high then players cannot join the party.
+     */
+    private final int partyLevel;
+
     private final MMOCorePartyModule module;
 
     public Party(MMOCorePartyModule module, PlayerData owner) {
         this.owner = owner;
         this.module = module;
+        this.partyLevel = owner.getLevel();
 
         addMember(owner);
     }
@@ -59,6 +68,10 @@ public class Party implements AbstractParty {
         return online;
     }
 
+    public int getLevel() {
+        return partyLevel;
+    }
+
     @Override
     public int countMembers() {
         return members.size();

src/main/resources/config.yml

@@ -143,10 +143,21 @@ party:
   # to talk in the party chat.
   chat-prefix: '@'
 
-  # The max players that can be in
-  # any given party. Between 2-8.
+  # The max amount of players in a party
+  # Has to be higher than 2
   max-players: 8
 
+  # If the difference between a player's level and the
+  # initial party owner's level is higher that this
+  # value, then that player can't join the party.
+  #
+  # This prevents low level players from joining
+  # high level players and earning tons of EXP.
+  #
+  # Set to the max level possible if you want to disable
+  # that feature.
+  max-level-difference: 3
+
 # Redirects vanilla experience obtained to MMOCore
 # class experience. You can define the % of the vanilla
 # experience that is being transfered as MMOCore exp.

src/main/resources/default/messages.yml

@@ -118,6 +118,7 @@ party-joined-other: '&6{player}&e joined your party!'
 transfer-party-ownership: '&eYou were transfered the party ownership.'
 kick-from-party: '&eYou successfully kicked &6{player}&e.'
 party-invite-cooldown: '&cPlease wait {cooldown} before inviting {player}.'
+high-level-difference: '&cYou cannot invite {player} as the level difference is too high.'
 
 # Guilds
 guild-chat: '&a[{tag}] {player}: {message}'