My problem is about properties and the virtuality of the methods. I would like to create a property whose get and set methods
are virtual. I had the same problems in Delphi before and the solution was the same. I created a private _get method and a public
get method. The former one will call the latter. The same stands for _set and set. Here is an example below:
class C1(object):
def namechanged(self):
"""Called after the name of the component has been changed."""
pass
def getname(self):
"""Returns the name of the component.
You can override this method to provide generated component names."""
return self._name
def setname(self,name):
"""Set the name of the component.
You can override this method to programatically control component name changes.
"""
self._name = name
self.namechanged()
def _getname(self):
"""Internal method, do not use"""
return self.getname()
def _setname(self,name):
"""Internal method, do not use"""
self.setname(name)
name = property(_getname,_setname,"Name")
class C2(C1):
def getname(self):
return "lala"class C3(C1):
def _getname(self):
return "lala"
name = property(_getname,None,"Name")
c1 = C1() c2 = C2() c3 = C3()
c1.name = 'Test1' c2.name = 'Test2' c3.name = 'Test3' print c1.name # This will print 'Test1' print c2.name # This will print 'lala' print c3.name # This will print 'lala' print C3.name is C1.name # False
I cannot override C2._getname instead, because c2.name would print 'Test2" instead of lala. Clearly, the property stores a reference to the get and set methods and it is not possible to have it use the new methods. Creating a new property is the worst - need to duplicate code and also C3.name is C1.name returns False. :-) It is not a big problem because I found the solution just I wonder if there is a better way to "virtualize" property get/set functions.
-- _________________________________________________________________ Laszlo Nagy web: http://designasign.biz IT Consultant mail: [EMAIL PROTECTED]
Python forever!
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