missing methods or __getattr__ problem

Uwe C. Schroeder uwe at oss4u.com
Wed Oct 2 20:14:06 CEST 2002


 
Hi, 
 
I'm a little stuck here and my brain turns in circles. 
Here's what I'm trying to accomplish and I'm sure there is a very 
simple solution to this problem: 
 
The caller calles a method xx.callme(objecttype, parameters) 
The called object keeps a list of class instances where the 
paricularly wanted object can be found via the "objecttype" 
parameter. However the called object itself doesn't have the called 
attribute. What I'm looking for is a way to transparently call a 
method as if it was part of the called object. So the called object 
has to do the following: 
1. figure out if the called attribute is a member of itself 
2. if not 1. take the first parameter and look up the object in 
which the wanted method resides 
3. call the (hopefully found) method and return the results. 
 
 
Using __getattr__ makes no sense since I need the parameters not 
only the name. Using __call__ and have __getattr__ redirect to 
__call__ won't work either since __call__ then has the paramters, 
but not the method name. 
How to do this ? 
 
Here's some code example: 
called object: 
 
OBJ_PROGRAM = 5999 
 
class bng: 
 
    def __init__(self): 
        # Objects is a class that keeps the references 
        # to instances of other objects containing 
        # the methods to call. It's much like a dict 
        self.obj=Objects(self.dbc)         
         
    def somefunction(self,bla): 
        pass 
 
    # This would be OK if I made a wrapper method for 
    # each method to be called 
    def getAllPrograms(self): 
        ob=self.obj.get(OBJ_PROGRAM)  
        return ob.getAll() 
 
 
caller: 
 
b=bng() 
print bng.getAllPrograms()  # works fine 
print bng.getAll(OBJ_PROGRAM) # how to do this ? 
 
Point is, that the final app will have hundreds of methods 
to be called. The calls come in via XML-RPC and are all mapped to 
the bng class instance. If I set up a wrapper for each method to be 
called the bng class will be HUGE and hard to maintain. 
 
Any help is appreciated. 
 
UC 
 
 



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