Write a Java Program to implement Adapter pattern for Enumeration iterator

 The Adapter Pattern is useful for making two incompatible interfaces compatible by creating a wrapper class (adapter) that allows one interface to be used as another. In this case, the problem requires creating an adapter to allow an Enumeration to be used as an Iterator.

Here's a well-organized Java program that implements the Adapter pattern, providing a class that adapts an Enumeration to an Iterator.

Solution Code

import java.util.Enumeration;
import java.util.Iterator;
import java.util.Vector;

// Adapter class to make Enumeration behave like an Iterator
class EnumerationIteratorAdapter<T> implements Iterator<T> {
    private Enumeration<T> enumeration;

    // Constructor that takes an Enumeration to adapt
    public EnumerationIteratorAdapter(Enumeration<T> enumeration) {
        this.enumeration = enumeration;
    }

    // hasNext() method of Iterator, adapted from Enumeration's hasMoreElements()
    @Override
    public boolean hasNext() {
        return enumeration.hasMoreElements();
    }

    // next() method of Iterator, adapted from Enumeration's nextElement()
    @Override
    public T next() {
        return enumeration.nextElement();
    }

    // Optional remove() method for Iterator; since Enumeration does not support removal, we throw an exception
    @Override
    public void remove() {
        throw new UnsupportedOperationException("Remove not supported.");
    }
}

public class AdapterPatternDemo {
    public static void main(String[] args) {
        // Creating an Enumeration using a Vector
        Vector<String> vector = new Vector<>();
        vector.add("Item1");
        vector.add("Item2");
        vector.add("Item3");
        Enumeration<String> enumeration = vector.elements();

        // Using the EnumerationIteratorAdapter to adapt the Enumeration to an Iterator
        Iterator<String> iterator = new EnumerationIteratorAdapter<>(enumeration);

        // Now we can use the Iterator methods (hasNext, next) on the Enumeration
        System.out.println("Iterating using the adapted Iterator:");
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }
    }
}

Explanation

• EnumerationIteratorAdapter: This adapter class implements Iterator and takes an Enumeration in the constructor. It provides hasNext() and next() methods by delegating to the hasMoreElements() and nextElement() methods of Enumeration.
• remove(): The Iterator interface requires a remove() method, but since Enumeration does not support removing elements, this method throws an UnsupportedOperationException.
• Main Demo: In main(), we create a Vector and obtain an Enumeration from it. We then wrap this Enumeration with EnumerationIteratorAdapter to use it as an Iterator.

Output

The program will print:

Iterating using the adapted Iterator:
Item1
Item2
Item3










Write a program to connect with the available Wi-Fi using Arduino.

To connect an Arduino to an available Wi-Fi network, you would typically use an Arduino-compatible Wi-Fi module, like the ESP8266 or ESP32. Here’s how you can use an ESP8266 module with Arduino to connect to Wi-Fi.
Requirements
Arduino IDE installed.
ESP8266/ESP32 board connected to your computer.
Wi-Fi credentials (SSID and password) of the network you want to connect to.
Steps to Program an ESP8266 or ESP32 to Connect to Wi-Fi
Install ESP8266/ESP32 Support in Arduino IDE (if not done yet):
Go to File > Preferences in the Arduino IDE.
In the Additional Board Manager URLs field, add:
For ESP8266: http://arduino.esp8266.com/stable/package_esp8266com_index.json
For ESP32: https://dl.espressif.com/dl/package_esp32_index.json
Go to Tools > Board > Boards Manager. Search for ESP8266 or ESP32 and install it.
Select the Correct Board and Port:
Go to Tools > Board and choose ESP8266 or ESP32 depending on your device.
Select the correct COM port in Tools > Port.
Example Code to Connect to Wi-Fi
Here is an example Arduino code that connects the ESP8266 or ESP32 to a Wi-Fi network:

#include <ESP8266WiFi.h> // For ESP8266
// #include <WiFi.h> // For ESP32 - uncomment if using ESP32 instead

// Replace with your network credentials
const char* ssid = "your_SSID";          // Your Wi-Fi SSID
const char* password = "your_PASSWORD";  // Your Wi-Fi Password

void setup() {
  Serial.begin(115200);         // Start Serial Communication at 115200 baud
  WiFi.begin(ssid, password);   // Connect to Wi-Fi
  
  Serial.print("Connecting to Wi-Fi");

  // Wait for connection
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  // Once connected
  Serial.println("\nConnected to Wi-Fi");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP()); // Print the IP address
}

void loop() {
  // Your code here; after connecting, the device can communicate over Wi-Fi
}
Code Explanation
Library Inclusion:
Use ESP8266WiFi.h for ESP8266 or WiFi.h for ESP32 to manage Wi-Fi functions.
Wi-Fi Credentials:
Enter your Wi-Fi SSID and password in the ssid and password variables.
Connecting to Wi-Fi:
The WiFi.begin(ssid, password); command initiates the connection to the specified Wi-Fi.
The while (WiFi.status() != WL_CONNECTED) loop continuously checks the connection status, waiting until the module connects.
Displaying IP Address:
Once connected, WiFi.localIP() retrieves and prints the module’s IP address to the Serial Monitor.
Testing
Upload the Code: Upload the code to your ESP8266 or ESP32.
Open Serial Monitor: Set the baud rate to 115200 in the Serial Monitor to see the connection status.
View IP Address: Once connected, you should see the IP address printed in the Serial Monitor.
This program demonstrates a basic connection to a Wi-Fi network, which can be used as a foundation for Internet of Things (IoT) applications involving data transfer, sensor readings, or communication with web servers.