code: public boolean hasRunOnMachine(String trackerHost, String trackerName) {
      return this.activeTasks.values().contains(trackerName) || 
        hasFailedOnMachine(trackerHost);
    }
docs: Was this task ever scheduled to run on this machine?
  @param trackerHost The task tracker hostname
  @param trackerName The tracker name
  @return Was task scheduled on the tracker?