Clean up chunk coordinators and queue coordinators (#3208)

Core/src/main/java/com/plotsquared/core/queue/ChunkCoordinator.java

@@ -25,24 +25,7 @@
  */
 package com.plotsquared.core.queue;
 
-import com.plotsquared.core.util.task.PlotSquaredTask;
-
-public abstract class ChunkCoordinator implements PlotSquaredTask {
-
-    private boolean cancelled = false;
-
-    @Override
-    public abstract void runTask();
-
-    @Override
-    public boolean isCancelled() {
-        return cancelled;
-    }
-
-    @Override
-    public void cancel() {
-        this.cancelled = true;
-    }
+public abstract class ChunkCoordinator implements Runnable {
 
     /**
      * Starts the chunk coordinator. This will usually (implementation-specific-permitting) mark chunks to be loaded in batches,
@@ -51,6 +34,11 @@ public abstract class ChunkCoordinator implements PlotSquaredTask {
      */
     public abstract void start();
 
+    /**
+     * Cancel the chunk coordinator.
+     */
+    public abstract void cancel();
+
     /**
      * Get the amount of remaining chunks (at the time of the method call)
      *

Core/src/main/java/com/plotsquared/core/queue/GlobalBlockQueue.java

@@ -29,18 +29,12 @@ import com.plotsquared.core.PlotSquared;
 import com.sk89q.worldedit.world.World;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.ConcurrentLinkedDeque;
-
 public class GlobalBlockQueue {
 
-    private final ConcurrentLinkedDeque<QueueCoordinator> activeQueues;
     private QueueProvider provider;
 
     public GlobalBlockQueue(@NonNull QueueProvider provider) {
         this.provider = provider;
-        this.activeQueues = new ConcurrentLinkedDeque<>();
     }
 
     /**
@@ -64,33 +58,4 @@ public class GlobalBlockQueue {
         this.provider = provider;
     }
 
-    /**
-     * Place an instance of {@link QueueCoordinator} into a list incase access is needed
-     * and then start it.
-     *
-     * @param queue {@link QueueCoordinator} instance to start.
-     * @return true if added to queue, false otherwise
-     */
-    public boolean enqueue(@NonNull QueueCoordinator queue) {
-        boolean success = false;
-        if (queue.size() > 0 && !activeQueues.contains(queue)) {
-            success = activeQueues.add(queue);
-            queue.start();
-        }
-        return success;
-    }
-
-    public void dequeue(@NonNull QueueCoordinator queue) {
-        queue.cancel();
-        activeQueues.remove(queue);
-    }
-
-    public @NonNull List<QueueCoordinator> getActiveQueues() {
-        return new ArrayList<>(activeQueues);
-    }
-
-    public boolean isDone() {
-        return activeQueues.size() == 0;
-    }
-
 }

Core/src/main/java/com/plotsquared/core/queue/QueueCoordinator.java

@@ -39,6 +39,9 @@ import com.sk89q.worldedit.world.World;
 import com.sk89q.worldedit.world.biome.BiomeType;
 import com.sk89q.worldedit.world.block.BaseBlock;
 import com.sk89q.worldedit.world.block.BlockState;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
@@ -51,6 +54,7 @@ public abstract class QueueCoordinator {
     private boolean forceSync = false;
     @Nullable
     private Object chunkObject;
+    private final AtomicBoolean enqueued = new AtomicBoolean();
 
     @Inject
     private GlobalBlockQueue blockQueue;
@@ -319,12 +323,17 @@ public abstract class QueueCoordinator {
     }
 
     /**
-     * Enqueue the queue with the {@link GlobalBlockQueue}
+     * Enqueue the queue to start it
      *
      * @return success or not
      */
     public boolean enqueue() {
-        return blockQueue.enqueue(this);
+        boolean success = false;
+        if (enqueued.compareAndSet(false, true)) {
+            success = true;
+            start();
+        }
+        return success;
     }
 
     /**
@@ -333,7 +342,7 @@ public abstract class QueueCoordinator {
     public abstract void start();
 
     /**
-     * Cancel the queue. Not yet implemented.
+     * Cancel the queue
      */
     public abstract void cancel();
 

Core/src/main/java/com/plotsquared/core/queue/subscriber/DefaultProgressSubscriber.java

@@ -107,11 +107,7 @@ public class DefaultProgressSubscriber implements ProgressSubscriber {
     @Override
     public void notifyProgress(@NonNull ChunkCoordinator coordinator, double progress) {
         this.progress.set(progress);
-        if (coordinator.isCancelled() || progress >= 1) {
-            if (task != null) {
-                task.cancel();
-            }
-        } else if (started.compareAndSet(false, true)) {
+        if (started.compareAndSet(false, true)) {
             TaskManager.getPlatformImplementation().taskLater(() -> task = TaskManager
                     .getPlatformImplementation()
                     .taskRepeat(() -> {