被观察者接口：

public interface IMonitorSubject {

    public void addListener(IMonitorListener listener);

    public void notifyListener(JobCtrl implJobCtrl);
}

观察者接口：

public interface IMonitorListener {
    public void statistical(JobCtrl implJobCtrl);
}

被观察者实现：

public class JobSubject implements IMonitorSubject {
    private final CopyOnWriteArraySet<IMonitorListener> monitorListener = new CopyOnWriteArraySet<>();

    @Override
    public void addListener(IMonitorListener listener) {
        monitorListener.add(listener);
    }

    @Override
    public void notifyListener(JobCtrl implJobCtrl) {
        for (IMonitorListener listener : monitorListener) {
            try {
                listener.statistical(implJobCtrl);
            } catch (Exception e) {
                Log.e("statistic jobs error.");
                Log.e(e);
            }
        }
    }
}

观察者实现：

public class JobListener implements IMonitorListener {
    private JobListener() {
    }

    static class SingletonHolder {
        static JobListener instance = new JobListener();
    }

    public static JobListener getInstance() {
        return SingletonHolder.instance;
    }

    @Override
    public void statistical(JobCtrl implJobCtrl) {
        //do some things.
    }
}

调用者：

public class JobMonitor{
    private IMonitorSubject subject = new JobSubject();
    private JobCtrl implJobCtrl= new JobCtrl();
    public JobMonitor(){
        subject.addListener(JobListener.getInstance());
    }

    @Override
    public static void main(String[] args) {
        Log.i("JobMonitorBuilder start[schedule]-----");
        subject.notifyListener(implJobCtrl);
        Log.i("JobMonitorBuilder end[schedule]-----");
        return null;
    }
}