Made builder pattern much simpler by removing unnecessary classes.

This follows the motto "a class with only one method that actually
does anything should be a function", with the result that using
the director function requires one line of code instead of 5.

Author: spookylukey

creational/builder.py

@@ -10,10 +10,10 @@
 from its actual representation (generally for abstraction).
 
 *What does this example do?
-This particular example uses a Director to abtract the
+This particular example uses a director function to abtract the
 construction of a building. The user specifies a Builder (House or
 Flat) and the director specifies the methods in the order necessary
-creating a different building dependding on the specified
+creating a different building depending on the specified
 specification (through the Builder class).
 
 @author: Diogenes Augusto Fernandes Herminio <[email protected]>
@@ -29,19 +29,11 @@
 """
 
 
-# Director
-class Director(object):
-
-    def __init__(self):
-        self.builder = None
-
-    def construct_building(self):
-        self.builder.new_building()
-        self.builder.build_floor()
-        self.builder.build_size()
-
-    def get_building(self):
-        return self.builder.building
+def construct_building(builder):
+    builder.new_building()
+    builder.build_floor()
+    builder.build_size()
+    return builder.building
 
 
 # Abstract Builder
@@ -93,14 +85,9 @@ def __repr__(self):
 
 # Client
 if __name__ == "__main__":
-    director = Director()
-    director.builder = BuilderHouse()
-    director.construct_building()
-    building = director.get_building()
+    building = construct_building(BuilderHouse())
     print(building)
-    director.builder = BuilderFlat()
-    director.construct_building()
-    building = director.get_building()
+    building = construct_building(BuilderFlat())
     print(building)
 
 ### OUTPUT ###

tests/test_builder.py

@@ -1,16 +1,13 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 import unittest
-from creational.builder import Director, BuilderHouse,  BuilderFlat
+from creational.builder import construct_building, BuilderHouse,  BuilderFlat
 
 
 class TestHouseBuilding(unittest.TestCase):
 
     def setUp(self):
-        self.director = Director()
-        self.director.builder = BuilderHouse()
-        self.director.construct_building()
-        self.building = self.director.get_building()
+        self.building = construct_building(BuilderHouse())
 
     def test_house_size(self):
         self.assertEqual(self.building.size, 'Big')
@@ -22,10 +19,7 @@ def test_num_floor_in_house(self):
 class TestFlatBuilding(unittest.TestCase):
 
     def setUp(self):
-        self.director = Director()
-        self.director.builder = BuilderFlat()
-        self.director.construct_building()
-        self.building = self.director.get_building()
+        self.building = construct_building(BuilderFlat())
 
     def test_house_size(self):
         self.assertEqual(self.building.size, 'Small')