As we continue our smart home system project, this unit will focus on two design patterns: the Command pattern and the Decorator pattern. These patterns will help us create a flexible and expandable system for automation and lighting control.

1. Basic Setup:

   • Abstract Device: Define an abstract class Device and derive specific device classes (Light, Fan) from it.
   • Factory Method: Implement factory classes to generate instances of these devices.

2. Command Pattern:

   • Purpose: Encapsulates a request as an object, allowing for parameterization, queuing, logging of requests, and support for undoable operations.
   • Components:
     • Define a ICommand interface and concrete command classes (LightOnCommand, LightOffCommand).
     • Implement a RemoteControl class to execute commands.

3. Decorator Pattern:

   • Purpose: Adds additional functionalities dynamically to existing objects without altering their structure.
   • Components:
     • Define a decorator class (ColoredLight) to add color functionalities to a Light device.

Let’s move forward and start implementing these patterns.

Before diving into the design patterns, we need to define the devices we'll be working with. We'll start by defining an abstract class Device. Then, create specific device classes Light and Fan that inherit from Device.

Next, implement a factory class to generate instances of these devices.

Now, we'll use the Command pattern to create flexible automation commands. For that, let's define a ICommand interface and the concrete command classes.

Let's also implement the remote control to execute commands.

Now, let's use the RemoteControl class in the Main program.

Next, we'll apply the Decorator pattern to enhance our lighting system. We'll define a decorator class ColoredLight to add color functionalities to a Light device.

Finally, we can use the decorator to add functionalities to devices.

By using the Command and Decorator design patterns, we have crafted a smart home system that is modular and flexible. These patterns enable you to extend functionality and dynamically add features without modifying the core structure.

Now it's your turn—get hands-on by implementing these patterns yourself. Let's bring your smart home system to life!