Python 设计模式 - 抽象工厂

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抽象工厂模式也称为工厂的工厂。这种设计模式属于创意设计模式类别。它提供了创建对象的最佳方法之一。

它包含一个接口，负责创建Factory相关的对象。

抽象工厂模式如何实现？

以下程序有助于实现抽象工厂模式。

class Window:
   __toolkit = ""
   __purpose = ""

   def __init__(self, toolkit, purpose):
      self.__toolkit = toolkit
      self.__purpose = purpose
   
   def getToolkit(self):
      return self.__toolkit
   
   def getType(self):
      return self.__purpose

class GtkToolboxWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "ToolboxWindow")

class GtkLayersWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "LayersWindow")

class GtkMainWindow(Window):
   def __init__(self):
      Window.__init__(self, "Gtk", "MainWindow")

class QtToolboxWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "ToolboxWindow")

class QtLayersWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "LayersWindow")

class QtMainWindow(Window):
   def __init__(self):
      Window.__init__(self, "Qt", "MainWindow")

# Abstract factory class
class UIFactory:
   def getToolboxWindow(self): pass
   def getLayersWindow(self): pass
   def getMainWindow(self): pass

class GtkUIFactory(UIFactory):
   def getToolboxWindow(self):
      return GtkToolboxWindow()
   def getLayersWindow(self):
      return GtkLayersWindow()
   def getMainWindow(self):
      return GtkMainWindow()

class QtUIFactory(UIFactory):
   def getToolboxWindow(self):
      return QtToolboxWindow()
   def getLayersWindow(self):
      return QtLayersWindow()
   def getMainWindow(self):
      return QtMainWindow()

if __name__ == "__main__":
   gnome = True
   kde = not gnome
   
   if gnome:
      ui = GtkUIFactory()
   elif kde:
      ui = QtUIFactory()
   
   toolbox = ui.getToolboxWindow()
   layers = ui.getLayersWindow()
   main = ui.getMainWindow()
   
   print "%s:%s" % (toolbox.getToolkit(), toolbox.getType())
   print "%s:%s" % (layers.getToolkit(), layers.getType())
   print "%s:%s" % (main.getToolkit(), main.getType())

输出

上述程序生成以下输出 -

解释

在上面的程序中，抽象工厂为每个窗口创建对象。它调用每个方法，该方法按预期执行输出。