Add BukkitTask#isCancelled

src/main/java/org/bukkit/craftbukkit/scheduler/CraftFuture.java

@@ -28,10 +28,6 @@ class CraftFuture<T> extends CraftTask implements Future<T> {
         return true;
     }
 
-    public boolean isCancelled() {
-        return getPeriod() == -2l;
-    }
-
     public boolean isDone() {
         final long period = this.getPeriod();
         return period != -1l && period != -3l;

src/main/java/org/bukkit/craftbukkit/scheduler/CraftTask.java

@@ -81,6 +81,11 @@ class CraftTask implements BukkitTask, Runnable {
         return task.getClass();
     }
 
+    @Override
+    public boolean isCancelled() {
+        return (period == -2l);
+    }
+
     public void cancel() {
         Bukkit.getScheduler().cancelTask(id);
     }