工厂方法实施

Question

我正在浏览SO中的“工厂方法”页面，并且遇到了这个link。 和this comment。这个例子看起来像一个变种，并认为以其原始方式实现：将实例化推迟到子类...

这是我的尝试。以下代码是否实现链接中指定示例的Factory模式？请验证并建议是否必须进行重新分解。

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

我想说，没关系，虽然在我看来过于复杂。你并不需要ScheduleTypeFactoryImpl课程。然后，您可以将UseScheduleTypeFactory类更改为ScheduleTypeFactory。

我在想什么是这样的：

公共类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; 
} 

}

，你可能想包括一个 '默认' 的情况。