Implement login/logout events for /magnet

src/dev/w1zzrd/invtweaks/command/MagnetCommandExecutor.java

@@ -241,7 +241,15 @@ public class MagnetCommandExecutor implements CommandExecutor {
         divIndex = (divIndex + 1) % subdivide;
     }
 
+    public void onMagnetLogout(final UUID magnet) {
+        if (magnetData.removeLogoutOnline(magnet))
+            updateMagnetismTask(true);
+    }
 
+    public void onMagnetLogin(final UUID magnet) {
+        if (magnetData.addLoginOnline(magnet))
+            updateMagnetismTask(false);
+    }
 
     public void onDisable() {
         data.storeData("magnets", magnetData);

src/dev/w1zzrd/invtweaks/listener/MagnetismListener.java

@@ -0,0 +1,41 @@
+package dev.w1zzrd.invtweaks.listener;
+
+import dev.w1zzrd.invtweaks.command.MagnetCommandExecutor;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerJoinEvent;
+import org.bukkit.event.player.PlayerKickEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+
+public class MagnetismListener implements Listener {
+
+    private final MagnetCommandExecutor magnetCommandExecutor;
+
+    public MagnetismListener(final MagnetCommandExecutor magnetCommandExecutor) {
+        this.magnetCommandExecutor = magnetCommandExecutor;
+    }
+
+    @EventHandler
+    public void onPlayerJoinEvent(final PlayerJoinEvent event) {
+        magnetCommandExecutor.onMagnetLogin(event.getPlayer().getUniqueId());
+    }
+
+    @EventHandler
+    public void onPlayerDisconnectEvent(final PlayerQuitEvent event) {
+        onLeave(event.getPlayer());
+    }
+
+    @EventHandler
+    public void onPlayerKickedEvent(final PlayerKickEvent event) {
+        onLeave(event.getPlayer());
+    }
+
+    private void onLeave(final Player player) {
+        magnetCommandExecutor.onMagnetLogout(player.getUniqueId());
+    }
+
+    private boolean shouldNotifyExecutor(final Player player) {
+        return magnetCommandExecutor.isMagnet(player);
+    }
+}