设计模式（七）之观察者模式

public interface IMonitorSubject {

public void addListener(IMonitorListener listener);

public void notifyListener(JobCtrl implJobCtrl);
}

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

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);
}
}
}
}

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.
}
}

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;
}
}