ParseFile.java

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

public class ParseFile {

    // Initializes the array list of ports by reading from the file config_peer.txt
    public static void loadConfigPeerFile() {
        try {
            File configPeerFile = new File("config_peer.txt");
            BufferedReader br = new BufferedReader(new FileReader(configPeerFile));

            String portStr;
            int id = 0;
            while ((portStr = br.readLine()) != null)
                TcpSocketController.availableTcpSockets.add(new TcpSocket(Integer.parseInt(portStr), id++));
        }
        catch (IOException e) {
            System.out.println("Error reading from config_peer.txt");
        }
    }

    /**
     * The static method that updates the config_peer.txt file with the available sockets
     * This will be called every time there is a modification to the list of available sockets
     */
    public static void writeConfigPeerFile() {
        try {
            FileWriter configPeerWriter = new FileWriter("config_peer.txt", false);
            for (TcpSocket socket : TcpSocketController.availableTcpSockets) {
                configPeerWriter.write(socket.getLocalPort() + "\n");
            }

            configPeerWriter.flush();
            configPeerWriter.close();
        }
        catch (IOException e) {
            System.out.println("Error writing to config_peer.txt");
        }
    }

    /**
     * The static method that updates the config_neighbors.txt file with the connected sockets
     * This will be called every time there is a modification to the list of connected sockets
     */
    public static void writeConfigNeighborsFile() {
        try {
            FileWriter configNeighborsWriter = new FileWriter("config_neighbors.txt", false);
            for (TcpSocket socket : TcpSocketController.connectedTcpSockets) {
                configNeighborsWriter.write(socket.getConnectionSocket().getRemoteSocketAddress().toString().substring(1) +  "\n");
            }

            configNeighborsWriter.flush();
            configNeighborsWriter.close();
        }
        catch (IOException e) {
            System.out.println("Error writing to config_neighbors.txt");
        }
    }

    /**
     * The static method that searches whether the indicated file exists
     * @param searchedName the name of the file in the form of string
     * @return true if the file is found in the shared folder
     */
    public static boolean fileFound(String searchedName) {
        final String filename = searchedName;
        File sharedDir = new File("shared");

        File[] searchResult = sharedDir.listFiles(new FilenameFilter() {
            public boolean accept(File file, String name) {
                return name.startsWith(filename);
            }
        });

        return searchResult.length > 0;
    }

    /**
     * The static method that returns the list of files with matched filenames
     * @param searchedName the name of the file in the form of string
     * @return the list of file names found in the shared folder
     */
    public static ArrayList<String> getExactNames(String searchedName) {
        final String filename = searchedName;
        File sharedDir = new File("shared");

        File[] searchResult = sharedDir.listFiles(new FilenameFilter() {
            public boolean accept(File file, String name) {
                return name.startsWith(filename);
            }
        });

        ArrayList<String> matches = new ArrayList<String>();
        for (File match : searchResult) {
            matches.add(match.getName());
        }

        return matches;
    }
}