Prevent save task overlaps (#1588)

src/main/java/world/bentobox/bentobox/BentoBox.java

@@ -203,8 +203,16 @@ public class BentoBox extends JavaPlugin {
 
             // Save islands & players data every X minutes
             Bukkit.getScheduler().runTaskTimer(instance, () -> {
-                playersManager.saveAll(true);
-                islandsManager.saveAll(true);
+                if (!playersManager.isSaveTaskRunning()) {
+                    playersManager.saveAll(true);
+                } else {
+                    getLogger().warning("Tried to start a player data save task while the previous auto save was still running!");
+                }
+                if (!islandsManager.isSaveTaskRunning()) {
+                    islandsManager.saveAll(true);
+                } else {
+                    getLogger().warning("Tried to start a island data save task while the previous auto save was still running!");
+                }
             }, getSettings().getDatabaseBackupPeriod() * 20 * 60L, getSettings().getDatabaseBackupPeriod() * 20 * 60L);
 
             // Make sure all flag listeners are registered.

src/main/java/world/bentobox/bentobox/managers/IslandsManager.java

@@ -88,6 +88,8 @@ public class IslandsManager {
     @NonNull
     private List<String> deletedIslands;
 
+    private boolean isSaveTaskRunning;
+
     /**
      * Islands Manager
      * @param plugin - plugin
@@ -1209,6 +1211,10 @@ public class IslandsManager {
         });
     }
 
+    public boolean isSaveTaskRunning() {
+        return isSaveTaskRunning;
+    }
+
     /**
      * Save the all the islands to the database
      */
@@ -1232,6 +1238,8 @@ public class IslandsManager {
             return;
         }
 
+
+        isSaveTaskRunning = true;
         Queue<Island> queue = new LinkedList<>(islandCache.getIslands());
         new BukkitRunnable() {
             @Override
@@ -1239,6 +1247,7 @@ public class IslandsManager {
                 for (int i = 0; i < plugin.getSettings().getMaxSavedIslandsPerTick(); i++) {
                     Island island = queue.poll();
                     if (island == null) {
+                        isSaveTaskRunning = false;
                         cancel();
                         return;
                     }

src/main/java/world/bentobox/bentobox/managers/PlayersManager.java

@@ -25,6 +25,8 @@ public class PlayersManager {
     private Map<UUID, Players> playerCache;
     private Set<UUID> inTeleport;
 
+    private boolean isSaveTaskRunning;
+
     /**
      * Provides a memory cache of online player information
      * This is the one-stop-shop of player info
@@ -59,6 +61,10 @@ public class PlayersManager {
         handler.loadObjects().forEach(p -> playerCache.put(p.getPlayerUUID(), p));
     }
 
+    public boolean isSaveTaskRunning() {
+        return isSaveTaskRunning;
+    }
+
     /**
      * Save all players
      */
@@ -82,6 +88,7 @@ public class PlayersManager {
             return;
         }
 
+        isSaveTaskRunning = true;
         Queue<Players> queue = new LinkedList<>(playerCache.values());
         new BukkitRunnable() {
             @Override
@@ -89,6 +96,7 @@ public class PlayersManager {
                 for (int i = 0; i < plugin.getSettings().getMaxSavedPlayersPerTick(); i++) {
                     Players player = queue.poll();
                     if (player == null) {
+                        isSaveTaskRunning = false;
                         cancel();
                         return;
                     }