Merge pull request mouredev#5694 from nlarrea/py-29

#29 - python

Author: Roswell468

Roadmap/29 - SOLID ISP/python/nlarrea.py

@@ -0,0 +1,189 @@
+"""
+ * EJERCICIO:
+ * Explora el "Principio SOLID de Segregación de Interfaces (Interface Segregation Principle, ISP)" 
+ * y crea un ejemplo simple donde se muestre su funcionamiento de forma correcta e incorrecta.
+ *
+ * DIFICULTAD EXTRA (opcional):
+ * Crea un gestor de impresoras.
+ * Requisitos:
+ * 1. Algunas impresoras sólo imprimen en blanco y negro.
+ * 2. Otras sólo a color.
+ * 3. Otras son multifunción, pueden imprimir, escanear y enviar fax.
+ * Instrucciones:
+ * 1. Implementa el sistema, con los diferentes tipos de impresoras y funciones.
+ * 2. Aplica el ISP a la implementación.
+ * 3. Desarrolla un código que compruebe que se cumple el principio.
+"""
+
+# To use interfaces
+from abc import ABC, abstractmethod
+
+
+# Incorrect
+
+
+class WorkerInterface(ABC):
+
+    @abstractmethod
+    def work(self):
+        pass
+
+    @abstractmethod
+    def eat(self):
+        pass
+
+
+class Human(WorkerInterface):
+    def work(self):
+        print("Working")
+
+    def eat(self):
+        print("Eating")
+
+
+class Robot(WorkerInterface):
+    def work(self):
+        print("Working")
+
+    def eat(self):
+        pass  # Robots don't eat
+
+
+""" What is wrong?
+- Interface has two methods, but one of its children classes doesn't use it.
+"""
+
+
+# Correct
+
+
+class WorkInterface(ABC):
+
+    @abstractmethod
+    def work(self):
+        pass
+
+
+class EatInterface(ABC):
+
+    @abstractmethod
+    def eat(self):
+        pass
+
+
+class Human(WorkInterface, EatInterface):
+    def work(self):
+        print("Working")
+
+    def eat(self):
+        print("Eating")
+
+
+class Robot(WorkInterface):
+    def work(self):
+        print("Working")
+
+
+human = Human()
+human.work()
+human.eat()
+
+robot = Robot()
+robot.work()
+
+"""
+Use only interfaces that are always necessary for the children. If one of the
+children doesn't use one of the methods, it's better to split the interface and
+add only the ones that are going to be implemented.
+"""
+
+
+"""
+ * DIFICULTAD EXTRA (opcional):
+ * Crea un gestor de impresoras.
+ * Requisitos:
+ * 1. Algunas impresoras sólo imprimen en blanco y negro.
+ * 2. Otras sólo a color.
+ * 3. Otras son multifunción, pueden imprimir, escanear y enviar fax.
+ * Instrucciones:
+ * 1. Implementa el sistema, con los diferentes tipos de impresoras y funciones.
+ * 2. Aplica el ISP a la implementación.
+ * 3. Desarrolla un código que compruebe que se cumple el principio.
+"""
+
+# Define interfaces
+
+
+class PrinterInterface(ABC):
+
+    @abstractmethod
+    def print(self, document: str):
+        pass
+
+
+class ColorPrinterInterface(ABC):
+
+    @abstractmethod
+    def print_color(self, document: str):
+        pass
+
+
+class ScannerInterface(ABC):
+
+    @abstractmethod
+    def scan(self, document: str) -> str:
+        pass
+
+
+class FaxInterface(ABC):
+
+    @abstractmethod
+    def send_fax(self, document):
+        pass
+
+
+# Create classes
+
+
+class Printer(PrinterInterface):
+    def print(self, document: str):
+        print(f"Printing (black & white): {document}")
+
+
+class ColorPrinter(ColorPrinterInterface):
+    def print_color(self, document: str):
+        print(f"Printing (color): {document}")
+
+
+class MultifunctionPrinter(
+    PrinterInterface, ColorPrinterInterface, ScannerInterface, FaxInterface
+):
+    def print(self, document: str):
+        print(f"Printing (black & white): {document}")
+
+    def print_color(self, document: str):
+        print(f"Printing (color): {document}")
+
+    def scan(self, document: str) -> str:
+        print(f"Scanning document: {document}")
+        return "scanned" + document
+
+    def send_fax(self, document):
+        print(f"Sending through fax: {document}")
+
+
+# Testing the classes
+
+DOCUMENT = "my-document.txt"
+
+printer = Printer()
+printer.print(DOCUMENT)
+
+color_printer = ColorPrinter()
+color_printer.print_color(DOCUMENT)
+
+multifunction_printer = MultifunctionPrinter()
+multifunction_printer.print(DOCUMENT)
+multifunction_printer.print_color(DOCUMENT)
+multifunction_printer.scan(DOCUMENT)
+multifunction_printer.send_fax(DOCUMENT)