GWT Place Class 增强可行性

Question

我正在进行思想实验，研究增强地点课程的可行性。假设 Google 会向我们提供这样的增强功能，那么对 Place 类的以下增强功能会有帮助吗？

假设 Place 类被增强为具有该方法

setActivity(Activity act)

然后，我们将能够这样做：

public class StartActivity extends AbstractActivity implements Presenter {

    private ClientFactory clientFactory;
    private String name;

    public StartActivity(StartPlace place, ClientFactory clientFactory) {
        this.clientFactory = clientFactory;
        this.name = place.getName();
        place.setActivity(this);
    }
}

这样 ActivityMapper 就会变得如此简单......

public class DenLapehActivityMapper
implements ActivityMapper{
    @Override
    public Activity getActivity(Place place){
            return place.getActivity();
    }
}

但是，我的思想实验，权衡了当前的情况，使我不得不做这些

abstract public class DenLapehPlace
extends  Place{
    private Activity activity;

    public Activity getActivity(){
        return activity;
    }

    public void setActivity(Activity activity){
        this.activity = activity;
    }
}

public class DenLapehActivityMapper
implements ActivityMapper{
    @Override
    public Activity getActivity(Place place){
        if (place instanceof DenLapehPlace)
            return ((DenLapehPlace)place).getActivity();

        return null;
    }
}

或者更糟糕的是，遵循示例/教程...

public class DenLapehActivityMapper
implements ActivityMapper{
    @Override
    public Activity getActivity(Place place){

        if (place instanceof AyamDenLapehPlace)
            return KurungAyamActivity;
        if (place instanceof ItekDenLapehPlace)
            return KurungItekActivity;
        if (place instanceof KabauDenLapehPlace)
            return KurungKabauActivity;
        if (place instanceof KancilDenLapehPlace)
            return KurungKancilActivity;        
        etc, etc, etc ...

        return null;
    }
}

如果您是 GWT 开发团队，是否会有任何技术动机（或消极动机）来进行此更改？如果您是 GWT 开发团队，那就更好了。你为什么不做出这个改变？

Answer 1

原因很简单，因为预计单个给定地点会有许多活动。

请参阅 http://blog.ltgt.net/gwt-21-activities/ 和http://blog.ltgt.net/gwt-21-activities-nesting-yagni/