Exercise (source) for Python Design Patterns

Author: MilovanTomasevic

src/2_exercises/1_CreationalPatterns/1_Builder/exercise_builder.py

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+class CodeBuilder:
+    def __init__(self, root_name):javascript:void(0)
+        # todo
+
+    def add_field(self, type, name):
+        # todo
+
+    def __str__(self):
+        # todo

src/2_exercises/1_CreationalPatterns/2_Factories/exercise_factories.py

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+class Person:
+    def __init__(self, id, name):
+        self.id = id
+        self.name = name
+
+class PersonFactory:
+    def create_person(self, name):
+        # todo

src/2_exercises/1_CreationalPatterns/3_Prototype/exercise_prototype.py

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+class Point:
+    def __init__(self, x=0, y=0):
+        self.x = x
+        self.y = y
+
+class Line:
+    def __init__(self, start=Point(), end=Point()):
+        self.start = start
+        self.end = end
+
+    def deep_copy(self):
+        # TODO

src/2_exercises/1_CreationalPatterns/4_Singleton/exercise_singleton.py

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+def is_singleton(factory):
+    # todo: call factory() and return true or false
+    # depending on whether the factory makes a
+    # singleton or not

src/2_exercises/2_StructuralPatterns/1_Adapter/exercise_adapter.py

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+class Square:
+    def __init__(self, side=0):
+        self.side = side
+
+def calculate_area(rc):
+    return rc.width * rc.height
+
+class SquareToRectangleAdapter:
+    def __init__(self, square):
+        # TODO

src/2_exercises/2_StructuralPatterns/2_Bridge/exercise_bridge.py

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+# class Shape:
+#     def __init__(self):
+#         self.name = None
+#
+#
+# class Triangle(Shape):
+#     def __init__(self):
+#         super().__init__()
+#         self.name = 'Triangle'
+#
+#
+# class Square(Shape):
+#     def __init__(self):
+#         super().__init__()
+#         self.name = 'Square'
+#
+#
+# class VectorSquare(Square):
+#     def __str__(self):
+#         return f'Drawing {self.name} as lines'
+#
+#
+# class RasterSquare(Square):
+#     def __str__(self):
+#         return f'Drawing {self.name} as pixels'
+
+# imagine VectorTriangle and RasterTriangle are here too
+
+class Renderer(ABC):
+    @property
+    def what_to_render_as(self):
+        return None
+        
+# TODO: reimplement Shape, Square, Triangle and Renderer/VectorRenderer/RasterRenderer

src/2_exercises/2_StructuralPatterns/3_Composite/exercise_composite.py

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+class SingleValue:
+    def __init__(self, value):
+        self.value = value
+
+class ManyValues(list):
+    pass

src/2_exercises/2_StructuralPatterns/4_Decorator/exercise_decorator.py

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+class Circle:
+  def __init__(self, radius):
+    self.radius = radius
+
+  def resize(self, factor):
+    self.radius *= factor
+
+  def __str__(self):
+    # todo
+
+class Square:
+  def __init__(self, side):
+    self.side = side
+
+  def __str__(self):
+    # todo
+
+
+class ColoredShape:
+  def __init__(self, shape, color):
+    self.color = color
+    self.shape = shape
+
+  def resize(self, factor):
+    # todo
+    # note that a Square doesn't have resize()
+
+  def __str__(self):
+    # todo

src/2_exercises/2_StructuralPatterns/5_Facade/exercise_fa‡ade.py

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+from random import randint
+
+class Generator:
+  def generate(self, count):
+    return [randint(1,9) for x in range(count)]
+
+class Splitter:
+  def split(self, array):
+    result = []
+
+    row_count = len(array)
+    col_count = len(array[0])
+
+    for r in range(row_count):
+      the_row = []
+      for c in range(col_count):
+        the_row.append(array[r][c])
+      result.append(the_row)
+
+    for c in range(col_count):
+      the_col = []
+      for r in range(row_count):
+        the_col.append(array[r][c])
+      result.append(the_col)
+
+    diag1 = []
+    diag2 = []
+
+    for c in range(col_count):
+      for r in range(row_count):
+        if c == r:
+          diag1.append(array[r][c])
+        r2 = row_count - r - 1
+        if c == r2:
+          diag2.append(array[r][c])
+
+    result.append(diag1)
+    result.append(diag2)
+
+    return result
+
+class Verifier:
+  def verify(self, arrays):
+    first = sum(arrays[0])
+
+    for i in range(1, len(arrays)):
+      if sum(arrays[i]) != first:
+        return False
+
+    return True
+
+class MagicSquareGenerator:
+  def generate(self, size):
+    # todo - return a magic square of the given size

src/2_exercises/2_StructuralPatterns/6_Flyweight/exercise_flyweight.py

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+class Sentence:
+    def __init__(self, plain_text):
+        # todo