Main Goal
My goal is to create a chat app for my company (they are all software developers). I first make a console version and if it is working fine, I will make a GUI version. The program will run on an exchange drive, so using networking features is not neccessary.
Project description
The software will consist of three programs. One is for managing the users: create a new one, delete a user, and so on. The second program is for displaying messages. The third program is for write messages. Later when I make a GUI version, all programs get united to one.
Current status
I have finished the user management program. If you want to test it on your local machine, you have to create a ".save" folder in the same directory your class files are. Otherwise the program crashes.
My Question
Is the code acceptable in matters of readability and code quality? Is there something to improve in matters of english grammar and writing?
(I dont want to implement high security features, because in my company we trust each other. Maybe I will write an Obfuscator class, that obfuscate the strings before they get stored on the disk, or something like that. But if you also have some hints in matters of security for me that are not to hard to implement, you can let me know.)
User.java
import java.io.Serializable;
public class User implements Serializable {
private String name;
private String password;
public User(String name, String password) {
setName(name);
setPassword(password);
}
public String getName() {
return new String(name);
}
public void setName(String name) {
this.name = name;
}
public void setPassword(String password) {
this.password = password;
}
public boolean checkPassword(String password) {
return this.password.equals(password);
}
}
UserManager.java
import java.util.List;
import java.util.ArrayList;
import java.io.File;
import java.io.Serializable;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.IOException;
public class UserManager implements Serializable {
private static final File SAVE_FILE = new File(".save/users");
private List<User> users;
public UserManager() {
if (SAVE_FILE.exists()) {
loadUsers();
} else {
users = new ArrayList<>();
saveUsers();
}
}
private void saveUsers() {
try (FileOutputStream fos = new FileOutputStream(SAVE_FILE);
ObjectOutputStream oos = new ObjectOutputStream(fos)) {
oos.writeObject(users);
} catch (IOException e) {
e.printStackTrace();
}
}
@SuppressWarnings("unchecked")
private void loadUsers() {
try (FileInputStream fis = new FileInputStream(SAVE_FILE);
ObjectInputStream ois = new ObjectInputStream(fis)) {
users = (ArrayList<User>) ois.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public User retainUser(String name, String password) {
for (User user : users) {
if (user.getName().equals(name) && user.checkPassword(password)) {
return user;
}
}
return null;
}
// returns a success message or an error message
public String createUser(String name, String password) {
if (name.isEmpty()) {
return "Name can't be empty.";
}
if (password.isEmpty()) {
return "Password can't be empty";
}
// check if name already exits
for (User user : users) {
if (user.getName().equals(name)) {
return "A user with that name already exists.";
}
}
User user = new User(name, password);
users.add(user);
saveUsers();
return "The new user was created successfully.";
}
public List<String> retainUserNames() {
List<String> userNames = new ArrayList<>();
for (User user : users) {
userNames.add(user.getName());
}
return userNames;
}
// returns true if delete request was successful
public boolean deleteUser(String name, String password) {
for (User user : users) {
if (user.getName().equals(name) && user.checkPassword(password)) {
users.remove(user);
saveUsers();
return true;
}
}
return false;
}
}
UserManagementProgram.java
import java.util.List;
import java.util.Scanner;
public class UserManagementProgram {
public static void main(String[] args) {
UserManagementProgram ump = new UserManagementProgram();
ump.mainLoop();
}
private Scanner scanner;
private UserManager userManager;
public UserManagementProgram() {
scanner = new Scanner(System.in);
userManager = new UserManager();
}
public void mainLoop() {
while (true) {
System.out.println("[1] Show all users");
System.out.println("[2] Create user");
System.out.println("[3] Delete user");
System.out.println("[4] Close");
System.out.print("Input: ");
String input = scanner.nextLine();
System.out.println();
switch (input) {
case "1":
printUsers();
break;
case "2":
createUser();
break;
case "3":
deleteUser();
break;
case "4":
return;
}
System.out.println();
}
}
private void printUsers() {
List<String> userNames = userManager.retainUserNames();
for (String name : userNames) {
System.out.println(name);
}
}
private void createUser() {
System.out.print("Name: ");
String name = scanner.nextLine();
System.out.print("Password: ");
String password = scanner.nextLine();
System.out.println(userManager.createUser(name, password));
}
private void deleteUser() {
System.out.print("Name: ");
String name = scanner.nextLine();
System.out.print("Password: ");
String password = scanner.nextLine();
if (userManager.deleteUser(name, password)) {
System.out.println("Success.");
} else {
System.out.println("Either name or password are incorrect.");
}
}
}
