Initializer.java

import java.io.*;
import java.util.*;

public class Initializer {
    
    // Read the config file and create routers
    public static List<Router> loadRouters(String filename) {
        List<Router> routers = new ArrayList<>();
        
        try {
            // Open the file
            BufferedReader reader = new BufferedReader(new FileReader(filename));
            
            // Read first line: number of routers
            String line = reader.readLine();
            int numRouters = Integer.parseInt(line.trim());
            
            System.out.println(" Loading " + numRouters + " routers...\n");
            
            // Read each router line
            for (int i = 0; i < numRouters; i++) {
                line = reader.readLine();
                if (line == null) break;
                
                // Parse: "R1: (R2, 140), (R4, 180)"
                String[] parts = line.split(":");
                String routerName = parts[0].trim();
                
                // Create the router
                Router router = new Router(routerName);
                
                // Parse neighbors: "(R2, 140), (R4, 180)"
                if (parts.length > 1) {
                    String neighborsStr = parts[1].trim();
                    String[] neighborPairs = neighborsStr.split("\\),");
                    
                    for (String pair : neighborPairs) {
                        // Remove parentheses and spaces
                        pair = pair.replace("(", "").replace(")", "").trim();
                        String[] neighborInfo = pair.split(",");
                        
                        if (neighborInfo.length == 2) {
                            String neighborName = neighborInfo[0].trim();
                            int cost = Integer.parseInt(neighborInfo[1].trim());
                            router.addNeighbor(neighborName, cost);
                        }
                    }
                }
                
                routers.add(router);
                System.out.println(" Created " + routerName);
            }
            
            reader.close();
            
            // Give each router the list of ALL routers
            List<String> allRouterNames = new ArrayList<>();
            for (Router r : routers) {
                allRouterNames.add(r.getName());
            }
            for (Router r : routers) {
                r.setAllRouters(allRouterNames);
            }
            
            System.out.println("\n All routers loaded successfully!\n");
            
        } catch (Exception e) {
            System.out.println(" Error reading file: " + e.getMessage());
            e.printStackTrace();
        }
        
        return routers;
    }
}