import java.util.HashMap;

import java.util.Map;

import java.util.function.Supplier;

public class ApiGuard {

private final Map<String, Object> apiHandlers;

public ApiGuard() {

this.apiHandlers = new HashMap<>();

}

public void registerHandler(String endpoint, Supplier<Object> handler) {

apiHandlers.put(endpoint, handler);

}

public Object execute(String endpoint) {

// Check if the endpoint has a registered handler

if (apiHandlers.containsKey(endpoint)) {

try {

// Execute the handler

return apiHandlers.get(endpoint).get();

} catch (Exception e) {

// Fallback logic in case of handler execution failure

System.err.println("Error executing endpoint " + endpoint + ": " + e.getMessage());

return fallback(); // Return a default value or handle the error

}

} else {

// Endpoint not found, return a default value or handle the error

System.err.println("Endpoint " + endpoint + " not found.");

return fallback();

}

}

// Define the fallback logic

private Object fallback() {

// Replace with your desired fallback behavior

System.out.println("Using fallback logic.");

return "Fallback Value";

}

public static void main(String[] args) {

ApiGuard guard = new ApiGuard();

// Register API handlers

guard.registerHandler("/users", () -> "User data");

guard.registerHandler("/products", () -> "Product catalog");

// Execute API endpoints

System.out.println(guard.execute("/users")); // Output: User data

System.out.println(guard.execute("/products")); // Output: Product catalog

System.out.println(guard.execute("/nonexistent")); // Output: Endpoint not found, then Fallback Value

}

}