Lab: 8.0.15

Objective:

• Understand the concept and importance of interfaces in Java development.
• Learn how to define and implement interfaces in Java.
• Explore practical applications of interfaces in real-world Java projects.
• Identify common pitfalls and best practices when working with interfaces.
• Gain hands-on experience with a complete Java example that demonstrates interfaces.

Prerequisites:

• Basic understanding of Java programming.
• Familiarity with creating classes and objects in Java.
• Understanding of inheritance in Java.
• Knowledge of abstract classes and methods.

What You'll Achieve:

• Develop a solid understanding of interfaces and their role in Java.
• Implement practical examples that can be applied in real-world scenarios.
• Enhance your skills in object-oriented design, polymorphism, and loose coupling.

Assignment Details

In this assignment, you will create a simple smart home system using interfaces. Follow these steps:

1. Create an interface called Device:
   • Declare methods: turnOn(), turnOff(), getStatus().
2. Create an interface called VoiceControlled:
   • Declare a method: voiceControl(String command).
3. Create a class SmartLight that implements both Device and VoiceControlled:
   • Add a private boolean field isOn.
   • Implement all methods from both interfaces.
   • voiceControl should accept commands like "on" or "off".
4. Create a class SmartThermostat that implements Device:
   • Add private fields for temperature and isOn.
   • Implement all methods from the Device interface.
   • Add a method setTemperature(int temp).
5. Create a class SmartSpeaker that implements both Device and VoiceControlled:
   • Add private fields for volume and isOn.
   • Implement all methods from both interfaces.
   • voiceControl should accept commands like "volume up", "volume down", "on", or "off".
6. Create a SmartHomeController class with a main method:
   • Create an array of Device objects containing instances of SmartLight, SmartThermostat, and SmartSpeaker.
   • Implement a method controlDevice(Device device) that turns the device on or off and prints its status.
   • Implement a method voiceControl(VoiceControlled device, String command) that sends voice commands to compatible devices.
   • Demonstrate the use of these methods with different devices.

Example Output

Smart Home System:

Controlling devices:
Smart Light is ON
Smart Thermostat is ON
Smart Speaker is ON

Voice controlling compatible devices:
Smart Light responded to voice command: on
Smart Speaker responded to voice command: volume up

Smart Light status: ON
Smart Thermostat status: ON (Temperature: 22°C)
Smart Speaker status: ON (Volume: 6)

Starter Code

The SmartHomeController.java file contains the following starter code:

package academy.javapro.lab;

interface Device {
    void turnOn();
    void turnOff();
    String getStatus();
}

interface VoiceControlled {
    void voiceControl(String command);
}

class SmartLight implements Device, VoiceControlled {
    // Implement this class
}

class SmartThermostat implements Device {
    // Implement this class
}

class SmartSpeaker implements Device, VoiceControlled {
    // Implement this class
}

public class SmartHomeController {
    public static void controlDevice(Device device) {
        // Implement this method
    }

    public static void voiceControl(VoiceControlled device, String command) {
        // Implement this method
    }

    public static void main(String[] args) {
        // Create devices and demonstrate the smart home system
    }
}

Hints

• Remember that interfaces in Java can only declare abstract methods (prior to Java 8) and constants.
• A class can implement multiple interfaces, allowing for a form of multiple inheritance of behavior.
• Use the instanceof operator to check if a Device is also VoiceControlled before attempting to use voice commands.
• Consider using enums for device states or command types to make your code more robust.
• Think about how interfaces promote loose coupling in your smart home system design.

Submission Instructions

1. Fork the repository
2. Clone your fork
3. Navigate into the repository
4. Implement the required classes and methods
5. Test your implementation with various inputs
6. Git add, commit, and push to your fork
7. Submit a pull request
   • Set the title of the pull request to your first name and last name
   • In the comment, briefly explain your implementation approach and any challenges you faced

Remember, the goal is to learn and have fun! Don't hesitate to ask for help if you get stuck.