[SOLVED] PlayerLoginEvent Error

Please read the error below.

Code:

09:38:13 [INFO] [EmergencyDowntime] padeius was kicked due to Downtime.
09:38:13 [SEVERE] Could not pass event PlayerLoginEvent to Essentials
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
    at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:30)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
    at net.minecraft.server.ServerConfigurationManager.attemptLogin(ServerConfigurationManager.java:227)
    at net.minecraft.server.NetLoginHandler.b(NetLoginHandler.java:102)
    at net.minecraft.server.NetLoginHandler.a(NetLoginHandler.java:41)
    at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:61)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:558)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:450)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
    at com.earth2me.essentials.EssentialsPlayerListener.onPlayerLogin(EssentialsPlayerListener.java:209)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:616)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
    ... 10 more
09:38:13 [INFO] Disconnecting padeius [/174.134.72.10:51952]: Server needs downtime! Check back in a few!

Here is my listener code.

Code:

@EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerLoginEvent event)
  {
    if (downtimekickall)
    {
      Player player = event.getPlayer();
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player.getName() + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      Player player = event.getPlayer();
      if (!player.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {
          event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player.getName() + " was kicked due to Downtime.");
      }
      else
      {
        player.sendMessage(plugin.getConfig().getString("OPWarning"));
      }
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

Please try and give me an understanding of what went wrong.

 

dakoslug
I don't know why Essentials is involved in this but I guess the reason why it's throwing the error is that you are cancelling the event of the login and when Essentials is trying to get the name of the player that joined, it gives it a nullpointer. If that is the case, you can fix it by changing the priority of this event to highest.

 

But shouldn't it remain on Lowest..because my plugin does this;
When the server needs downtime and another player joins, it checks if the player is OP...if the player is not OP..it should kick them.

I think I believe i saw a thread saying the lowest priority plugin gets the last say after all the other plugins already did. Is this the case?]

NVM: It's seems i got this backwards. Just to clarify...HIGHEST priority means the plugin that has teh final say?

 

dakoslug
Yes, that is usually the case. However, looking at the source code of Essentials, I found that it runs a delayed task after the player joins. This may be the cause of the issue. I still recommend you change priority to high.

 

OK I'm now confused... quote from Dinnerbone

He also says after Highest, nothing should change the outcome of the event. Because Monitor shouldn't change the outcome it should only...well monitor the event.
So then highest gets the last say?

 

dakoslug
You know, actually, the cause of the problem is not even a matter of priority. The thing is that in a PlayerLoginEvent, players who join are registered as really joining the server. What you are doing right now is kicking them AFTER they join the server, which will cause all sorts of issues. Use PlayerPreLogin event to resolve this.

Code:

@EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerPreLoginEvent event)
  {
    if (downtimekickall)
    {
      String player = event.getPlayer().getName();
      Player p = Bukkit.getPlayer(player);
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player.getName() + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      String player = event.getPlayer().getName();
      if (!p.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {
          event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player.getName() + " was kicked due to Downtime.");
      }
      else
      {
        p.sendMessage(plugin.getConfig().getString("OPWarning"));
      }
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

 

Do you mean

Code:

public void  onPlayerLogin(PlayerPreLoginEvent event)

and i'm getting errors on line 21,23,27,28,31 and 35. All related to the string player..it starts with getPlayer().
Btw I appreciate your help.

 

dakoslug
Yes, there aren't Player variables in PlayerPreLoginEvent. You have to get the player's name and store it as a string. I've updated the code above as reference.

 

Is this code good..?

Code:

package me.dakoslug.EmergencyDowntime;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerPreLoginEvent;
 
public class EmergencyDowntimeplayerListener implements Listener
{
  public static boolean downtimefull = false;
  public static boolean downtimekickall = false;
  public static boolean downtimebuild =  false;
  public static EmergencyDowntime plugin;
  @EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerPreLoginEvent event)
  {
    if (downtimekickall)
    {
      String player = event.getName();
      Player p = Bukkit.getPlayer(player);
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      String player = event.getName();
      Player p = Bukkit.getPlayer(player);
      if (!p.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {
          event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
      }
      else
      {
        p.sendMessage(plugin.getConfig().getString("OPWarning"));
      }
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

Does it work as intended?

 

dakoslug
Yes, it works before the JoinEvent activates so the error should be removed.

 

Thanks for everything

 

dakoslug
Np. Try it out and please post the results below.

 

It was a user reported problem.Could I re-test the issue by making a new server with essentials? Or is there some config option that created the error?

 

dakoslug
I'm pretty sure that the problem lies in the conflict with essentials itself unless the essentials feature was togglable. Try creating a test server with just essentials.

 

I used the old version of the plugin(the one that had an error) , with essentials and it produced no errors...Hmmm

Nvm..it does recreate the error with the old version and essentials..
But with the new version, the plugin won't kick the player at all...why?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

dakoslug
Use your server in online mode. Offline mode won't trigger the event for some reason.

 

r0306

Did exactly what you said, but now it spits an error after putting it online mode. And it still doesnt kick the player.

 

dakoslug
Cast string to player instead.

Code:

package me.dakoslug.EmergencyDowntime;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerPreLoginEvent;
 
public class EmergencyDowntimeplayerListener implements Listener
{
  public static boolean downtimefull = false;
  public static boolean downtimekickall = false;
  public static boolean downtimebuild =  false;
  public static EmergencyDowntime plugin;
  @EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerPreLoginEvent event)
  {
    if (downtimekickall)
    {
      String player = event.getName();
      Player p = (Player) player;
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      String player = event.getName();
      Player p = (Player) player;
      if (!p.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {
          event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
      }
      else
      {
        p.sendMessage(plugin.getConfig().getString("OPWarning"));
      }
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

 

r0306
Errors: Can not cast string from player

(if that was pseudo code..im still learning java..so I need to be hand held a little)

 

dakoslug
Ok. It turns out you can't directly cast from string to player. However, you can cast an offline player to a player.

Code:

package me.dakoslug.EmergencyDowntime;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerPreLoginEvent;
 
public class EmergencyDowntimeplayerListener implements Listener
{
  public static boolean downtimefull = false;
  public static boolean downtimekickall = false;
  public static boolean downtimebuild =  false;
  public static EmergencyDowntime plugin;
  @EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerPreLoginEvent event)
  {
    if (downtimekickall)
    {
      String player = event.getName();
      Player p = (Player) Bukkit.getOfflinePlayer(player);
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      String player = event.getName();
      Player p = (Player) player;
      if (!p.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {
          event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
      }
      else
      {
        p.sendMessage(plugin.getConfig().getString("OPWarning"));
      }
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

 

r0306

This time only line 30 says Can not cast string from player
NVM..repasted the code
Player p = (Player) Bukkit.getOfflinePlayer(player);

Error again:

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

dakoslug
Arrgh lol. Okay so it's impossible to check for permissions in this event because we can't get the player instance from the event. Can you remove these lines for now just for the sake of testing to see if the error is resolved?

Code:

      Player p = (Player) Bukkit.getOfflinePlayer(player);
      if (!p.hasPermission("emergencydowntime.exempt")) // ! Operator means instead of  == true its  == false
      {

      }
        p.sendMessage(plugin.getConfig().getString("OPWarning"));

 

Error remains :/ I guess it's not permissions of an offline player.

 

dakoslug
Change your code to this:

Code:

package me.dakoslug.EmergencyDowntime;
import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockPlaceEvent;
import org.bukkit.event.player.PlayerLoginEvent;
import org.bukkit.event.player.PlayerPreLoginEvent;
 
public class EmergencyDowntimeplayerListener implements Listener
{
  public static boolean downtimefull = false;
  public static boolean downtimekickall = false;
  public static boolean downtimebuild =  false;
  public static EmergencyDowntime plugin;
  @EventHandler(priority = EventPriority.LOWEST)
  public void  onPlayerLogin(PlayerPreLoginEvent event)
  {
    if (downtimekickall)
    {
      String player = event.getName();
      event.disallow(null, plugin.getConfig().getString("Kickmessage"));
      plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
    }
    if (downtimefull)
    {
      String player = event.getName();
        event.disallow(null, plugin.getConfig().getString("Kickmessage"));
        plugin.log.info("[EmergencyDowntime] " + player + " was kicked due to Downtime.");
    }
  }
  @SuppressWarnings("static-access")
public EmergencyDowntimeplayerListener(EmergencyDowntime plugin)
  {
      this.plugin = plugin;
  }
}

 

r0306

Yeah! That worked..but theres no way to get permission check ?? :c

 

dakoslug
Well, I looked everywhere for a permissions check for OfflinePlayer or String but I guess the only way to do so would be to read the permissions file directly or to create your own config file to define who can/can't join. (However, you can use .isOp() check for OfflinePlayer).

 

Then..is there a way to make the original code back in the first post work without the error?
isOP() hmm.
And how could I define the people allowed, which are the people who have the permission into a list which i can call on?

 

dakoslug
Hmm. I don't think there is a way to do that. However, on your enable method, you can call up a list of registered players and sync them with your list in config.

 

Right then when they are online, see if they have the permissions. Wow this is MUCH MORE complex that it was supposed to be..woww...theres no way to keep it simple eh?

 

dakoslug
I'm not really aware of any other handlers that are triggered before the player joins the server. Since not many plugins use this handler, I find that using it prevents conflicts from occurring.