工廠方法實施

Question

我正在瀏覽SO中的「工廠方法」頁面，並且遇到了這個link。 和this comment。這個例子看起來像一個變種，並認爲以其原始方式實現：將實例化推遲到子類...

這是我的嘗試。以下代碼是否實現鏈接中指定示例的Factory模式？請驗證並建議是否必須進行重新分解。

public class ScheduleTypeFactoryImpl implements ScheduleTypeFactory { 

    @Override 
    public IScheduleItem createLinearScheduleItem() { 
      return new LinearScheduleItem(); 
    } 

    @Override 
    public IScheduleItem createVODScheduleItem() { 
    return new VODScheduleItem(); 
    } 

} 

public class UseScheduleTypeFactory { 

    public enum ScheduleTypeEnum { 
     CableOnDemandScheduleTypeID, 
      BroadbandScheduleTypeID, 
      LinearCableScheduleTypeID, 
      MobileLinearScheduleTypeID 
    } 

    public static IScheduleItem getScheduleItem(ScheduleTypeEnum scheduleType) { 
     IScheduleItem scheduleItem = null; 
     ScheduleTypeFactory scheduleTypeFactory = new ScheduleTypeFactoryImpl(); 
     switch (scheduleType) { 
     case CableOnDemandScheduleTypeID: 
      scheduleItem = scheduleTypeFactory.createVODScheduleItem(); 
      break; 

     case BroadbandScheduleTypeID: 
      scheduleItem = scheduleTypeFactory.createVODScheduleItem(); 
      break; 

     case LinearCableScheduleTypeID: 
      scheduleItem = scheduleTypeFactory.createLinearScheduleItem(); 
      break; 

     case MobileLinearScheduleTypeID: 
      scheduleItem = scheduleTypeFactory.createLinearScheduleItem(); 
      break; 
     default: 
      break; 
     } 
     return scheduleItem; 
    } 
} 

Answer 1

我想說，沒關係，雖然在我看來過於複雜。你並不需要ScheduleTypeFactoryImpl課程。然後，您可以將UseScheduleTypeFactory類更改爲ScheduleTypeFactory。

我在想什麼是這樣的：

公共類ScheduleTypeFactory {

public enum ScheduleTypeEnum { 
    CableOnDemandScheduleTypeID, 
     BroadbandScheduleTypeID, 
     LinearCableScheduleTypeID, 
     MobileLinearScheduleTypeID 
} 

public static IScheduleItem getScheduleItem(ScheduleTypeEnum scheduleType) { 
    IScheduleItem scheduleItem = null; 
    switch (scheduleType) { 
    case CableOnDemandScheduleTypeID: 
     scheduleItem = new VODScheduleItem(); 
     break; 

    case BroadbandScheduleTypeID: 
     scheduleItem = new VODScheduleItem(); 
     break; 

    case LinearCableScheduleTypeID: 
     scheduleItem = new LinearScheduleItem(); 
     break; 
    case MobileLinearScheduleTypeID: 
     scheduleItem = new LinearScheduleItem(); 
     break; 
    default: 
     break; 
    } 
    return scheduleItem; 
} 

}

，你可能想包括一個 '默認' 的情況。