Remove the chunk from the pending operation queue's when it is removed.

rvandoosselaer#24

src/main/java/com/rvandoosselaer/blocks/ChunkManager.java

@@ -189,6 +189,8 @@ public void removeChunk(Chunk chunk) {
         assertInitialized();
 
         if (chunk != null) {
+            cancelAllPendingOperations(chunk);
+
             cache.evict(chunk.getLocation());
         }
     }
@@ -575,6 +577,20 @@ private void performCacheMaintenance() {
         }
     }
 
+    /**
+     * Cancel all pending operations for this chunk. When invoked, the chunk will be remove from all queues.
+     *
+     * @param chunk to cancel operations for
+     */
+    private void cancelAllPendingOperations(Chunk chunk) {
+        if (log.isDebugEnabled()) {
+            log.debug("Stopping pending tasks for {}", chunk);
+        }
+        loadingQueue.remove(chunk.getLocation());
+        generatorQueue.remove(chunk.getLocation());
+        meshQueue.remove(chunk);
+    }
+
     /**
      * Helper method to add an element to a queue, making sure we don't add the same element multiple times.
      *