我可以这样做：class SuperClass(object):
def __init__(self):
if type(self) == SuperClass:
raise Exception(" must be subclassed.")
# assert(type(self) == SuperClass)
class SubClass(SuperClass):
def __init__(self):
SuperClass.__init__(self)
subC = SubClassOne()
supC = SuperClass() # This line should throw an exception
运行时(引发异常！)以下内容：[ 18:32 jon@hozbox ~/so/python ]$ ./preventing-direct-instantiation.py
Traceback (most recent call last):
File "./preventing-direct-instantiation.py", line 15, in
supC = SuperClass()
File "./preventing-direct-instantiation.py", line 7, in __init__
raise Exception(" must be subclassed.")
Exception: must be subclassed.
编辑(来自评论)：[ 20:13 jon@hozbox ~/SO/python ]$ cat preventing-direct-instantiation.py
#!/usr/bin/python
class SuperClass(object):
def __init__(self):
if type(self) == SuperClass:
raise Exception(" must be subclassed.")
class SubClassOne(SuperClass):
def __init__(self):
SuperClass.__init__(self)
class SubSubClass(SubClassOne):
def __init__(self):
SubClassOne.__init__(self)
class SubClassTwo(SubClassOne, SuperClass):
def __init__(self):
SubClassOne.__init__(self)
SuperClass.__init__(self)
subC = SubClassOne()
try:
supC = SuperClass()
except Exception, e:
print "FAILED: supC = SuperClass() - %s" % e
else:
print "SUCCESS: supC = SuperClass()"
try:
subSubC = SubSubClass()
except Exception, e:
print "FAILED: subSubC = SubSubClass() - %s" % e
else:
print "SUCCESS: subSubC = SubSubClass()"
try:
subC2 = SubClassTwo()
except Exception, e:
print "FAILED: subC2 = SubClassTwo() - %s" % e
else:
print "SUCCESS: subC2 = SubClassTwo()"
印刷品：[ 20:12 jon@hozbox ~/SO/python ]$ ./preventing-direct-instantiation.py
FAILED: supC = SuperClass() - must be subclassed.
SUCCESS: subSubC = SubSubClass()
SUCCESS: subC2 = SubClassTwo()