Python 版 Instance Activator

之前写一个Python 版本的DbRowFactory(链接),   在初始化DbRowFactory时候, 除了要传cursor外, 还需要传一个RowClass类, 还有一个RowClass类的模块名, 用起来不爽, 改造了一下. 这个事情的一个副产品Python 版 Intance Activator, 代码如下:   

最新的代码和DbRowFactory都放在codeplex上了.

#! /usr/bin/env python
#coding=utf-8

import inspect
import sys

__author__ = 'Harry Liu, <harrychinese@gmail.com>'
__date__ = '16 Feb 2012'
__version__="0001"

##reference doc
#
#http://stackoverflow.com/questions/4513192/python-dynamic-class-names
#http://stackoverflow.com/questions/1796180/python-get-list-of-al-classes-within-current-module

def createIntance(full_class_name,*args,**kwargs):
'''
instantiate class dynamically
[arguments]
full_class_name: full class name that you want to instantiate, included package and module name if has
*args: list style arguments in class constructor
*kwargs: dict style arguments in class constructor
[return]
an instance of this full_class_name
[example]
import pyObjectCreator
full_class_name="knightmade.logging.Logger"
logger=pyObjectCreator.create_intance(full_class_name,'logname')
'''
class_meta=getClassMeta(full_class_name)
if class_meta!=None:
obj=class_meta(*args,**kwargs)
else:
obj=None
return obj


def getClassMeta(full_class_name):
'''
get class meta object of full_class_name, then we can use this meta object to instantiate full_class_name
[arguments]
full_class_name: full class name that you want to instantiate, included package and module name if has
[return]
an instance of this full_class_name
[example]
import pyObjectCreator
full_class_name="knightmade.logging.Logger"
loggerMeta=pyObjectCreator.getClassMeta(full_class_name)
'''
namespace=full_class_name.strip().rsplit('.',1)
if len(namespace)==1:
class_name=namespace[0]
class_meta=_getClassMetFromCurrModule(class_name)
else:
module_name=namespace[0]
class_name=namespace[1]
class_meta=_getClassMetaFromOtherModule(class_name,module_name)
return class_meta


def _getClassMetFromCurrModule(class_name):
result=None
module_name="__main__"
for name, obj in inspect.getmembers(sys.modules[module_name]):
if inspect.isclass(obj):
if name==class_name:
result=obj
break
return result


def _getClassMetaFromOtherModule(class_name, module_name):
module_meta=__import__(module_name,globals(), locals(),[class_name])
if module_meta!=None:
class_meta=getattr(module_meta,class_name)
else:
class_meta=None
return class_meta