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inherited and associated / composite objects
Applying OO design techniques and best practise example from a Well House Consultants training course
More on Applying OO design techniques and best practise [link]

This example is described in the following article(s):
   • Inheritance, Composition and Associated objects - when to use which - Python example - [link]

Source code: t6 Module: Y116

# We have TABLES of various sorts in a room
# Associated with each table we have a waitress and multiple customers

# We're running a restuarant, seating guests, etc!

class person (object):
        def getname(this):
                return this.name

class customer(person):
        def __init__(this,name,partysize):
                this.name = name
                this.partysize = partysize
        def getsize(this):
                return this.partysize

class waitress(person):
        def __init__(this,name,capacity):
                this.name = name
                this.capacity = capacity
                this.ccc = 0 # current customer count / not yet used

# ---------------------------------------------------

class table(object):
        def __init__(current,material,w,h,wt):
                current.w = w
                current.h = h
                current.place = 925
        def getbums(current):
                side = int(current.w/current.place)
                wide = int(current.h/current.place)
                return 2 * (side + wide)
        def setplace(current,p):
                current.place = p
        def getdoggie(current):
                if current.w < current.h:
                        return current.w/2
                return current.h/2
        def sng(current,material,wt):
                current.wt = wt
                current.m = material
                current.parties = []
        def getwaitstaff(self):
                return self.wt.getname()
        def seatguests(self,pname):
                so_far = self.getseated() # already at table
                adding = pname.getsize() # wanting to join
                holds = self.getbums() # capacity of table

                if holds >= so_far + adding:
                        return True

                return None

        def getseated(self):
                so_far = 0
                for pty in self.parties:
                        so_far += pty.getsize()
                return so_far

class recttable(table):

class squaretable(table):
        def __init__(current,material,w,wt):
                current.w = w
                current.h = w
                current.place = 925

class roundtable(table):
        def __init__(current,material,w,wt):
                current.w = w
                current.h = w
                current.place = 800
        def getbums(current):
                side = int(current.w * 3.14159265 / current.place)
                return side

# ----------------------------------------------

if __name__ == "__main__":

        lead = waitress("Heather",12)
        assist = waitress("Poppy",10)

        cafe = [recttable("Cherry",2100,980,lead),
                squaretable("oak",5000,assist) ]

        for tab in cafe:
                ps1 = tab.getbums()
                dog = tab.getdoggie()
                order = tab.getwaitstaff()
                print "We can seat",ps1,"and doggie distance is",dog,"order from",order

        if cafe[0].seatguests(customer("Alex",4)):
                print "We have seated Alex"

        if cafe[0].seatguests(customer("Simon",3)):
                print "We have seated Simon"

        for tab in cafe:
                ps1 = tab.getbums()
                ps2 = tab.getseated()
                order = tab.getwaitstaff()
                print "We have",ps2,"at a table for",ps1,"looked after by",order

# ------------------------------------------------------

""" Sample Output

munchkin:opy grahamellis$ python tabby
We can seat 6 and doggie distance is 490 order from Heather
We can seat 2 and doggie distance is 375 order from Poppy
We can seat 5 and doggie distance is 750 order from Heather
We can seat 20 and doggie distance is 2500 order from Poppy
We have seated Alex
We have 4 at a table for 6 looked after by Heather
We have 0 at a table for 2 looked after by Poppy
We have 0 at a table for 5 looked after by Heather
We have 0 at a table for 20 looked after by Poppy
munchkin:opy grahamellis$


Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Python
 * Python Programming
 * Intermediate Python
Also available on on site courses for larger groups

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Other Examples
This example comes from our "Applying OO design techniques and best practise" training module. You'll find a description of the topic and some other closely related examples on the "Applying OO design techniques and best practise" module index page.

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