Designing classes in python

I am designing a class which produces information like cpu usage,disk usage,Mem usage,...... for 3 systems,lets say data centers which has many workstations and work stations has many PCs.So the CPU usage and the other parameters are required for all the 3 levels(Datacenters, Workstations, Pcs). Please suggest is the bel开发者_StackOverflowow class design correct or how it is to be designed

EDIT

class Datacenters:
 def __init__(self,name,location,cpu,mem):
  self.name=name
  self.location=location
  self.cpu=cpu
  self.mem=mem

 def  getparam(self):
  return self.name,self.location ,self.cpu,self.mem

 def  getname(self):
  return self.name

class WS(Datacenters):
 def __init__(self,name,location,cpu,mem,obj):
  #datacentername = Datacenters.__init__(self) #To which data center it is associated
  obj.getname() #To which data center it is associated

  self.name=name
  self.location=location
  self.cpu=cpu
  self.mem=mem

def  getparam(self,obj):
  return self.name,self.location ,self.cpu,self.mem,obj.getname()

def  getpcname(self):
  return self.name

class Pcs(WS):
 def __init__(self,name,location,cpu,mem,obj):
  obj.getpcname() #To which WS it is  associated
  self.name=name
  self.location=location
  self.cpu=cpu
  self.mem=mem

 def  getparam(self,obj):
  return self.name,self.location ,self.cpu,self.mem,obj.getpcname()


a = Datacenters("dc1","Bl1",20,30)
print a.getparam()
b = WS("WS1","Bl1",20,30,a)
print b.getparam(a)
c = Pcs("PC1","Bl1",20,30,b)
print c.getparam(b)

---

Much of your code is pointless. I removed the lines that isn't needed:

class Datacenter:
    def __init__(self,name,location,cpu,mem):
        self.name=name
        self.location=location
        self.cpu=cpu
        self.mem=mem

class Workstation:
    def __init__(self,name,location,cpu,mem,datacenter):
        self.name=name
        self.location=location
        self.cpu=cpu
        self.mem=mem
        self.datacenter=datacenter

class Computer:
    def __init__(self,name,location,cpu,mem,workstation):
        # This line does nothing:
        self.name=name
        self.location=location
        self.cpu=cpu
        self.mem=mem
        self.workstation=workstation

You don't need to write accessor methods in Python. Just access the attributes directly. Also, the line obj.getname() did nothing.

And of course, as pointed out by others here, since when does a Datacenter have a CPU? And doesn't a Computer have the same location as a Workstation? Then it doesn't need the location. Probably your code should look like this:

class Datacenter:
    def __init__(self,name,location):
        self.name=name
        self.location=location

class Workstation:
    def __init__(self,name,location,datacenter):
        self.name=name
        self.location=location
        self.datacenter=datacenter

class Computer:
    def __init__(self,name,cpu,mem,workstation):
        # This line does nothing:
        self.name=name
        self.cpu=cpu
        self.mem=mem
        self.workstation=workstation

   def location(self):
       return self.workstation.location

   def datacenter(self):
       return self.workstation.datacenter

---

Some suggestions:

• Use 4-spaces indentation
• Use properties instead of getters, provide single properties, not a single one for all parameters (because parameters might be added later or by subclassing). In order to use properties, derive the base class from object (new style classes)
• Use singular class names, "Datacenter" instead of "Datacenters", because a single instance doesn't represent multiple datacenters, right?
• Don't call parameters "obj"
• So, a datacenter has a CPU? And a workstation is a datacenter, and gets a datacenter as an argument? Whaaat?

These points were mostly about coding style. I can't really help you with your use case - hope you get the point that your class hierarchy is totally screwed?!

---

What does this even mean?

   class WS(Datacentres):
      name
      location
      cpu
      mem

Your design sounds wrong anyway. If a Datacenter has workstations, why would workstation inheit from datacenter? A workstation isn't a datacenter.

http://en.wikipedia.org/wiki/Has-a

---

You shouldn't use inheritance here in that way, since Pcs is not WS and WS is not Datacentres.

You can make a class UnitInfo which has all that fields (name, cpu...) and use the instances of that class in DataCentres, WS, Pcs, because there is "has" relationship here (and not "is").

Or, make a class called Unit (or Units, I don't understand why you use plural forms), and inherit from that class. Unit "has" "name, "cpu-usage" and so on. "Pc" is a Unit. Maybe Unit is not the appropriate name for that class though.