public synchronized boolean cancel() {
    if (this.taskFuture != null && this.taskFuture.cancel(true)) {
      this.taskStateTracker.onTaskRunCompletion(this);
      this.completeShutdown();
      return true;
    } else {
      return false;
    }
  }
public synchronized boolean cancel ( ) { if ( this . taskFuture != null && this . taskFuture . cancel ( true ) ) { this . taskStateTracker . onTaskRunCompletion ( this ) ; this . completeShutdown ( ) ; return true ; } else { return false ; } }
return true if the task is successfully cancelled.
@return