Why JavaFX stucks when running a process? - mysql

Question

I am building an application using JavaFX. Application does some CRUD operations with the MySQL Database. So currently, I have 2 functions.
User Registration.
Email Validation (Check if email already exists in the database).
User registration is called in a JFoenix Button event. When it clicked it is calling separate 3 functions in another class as follows,
public static int insertUser(User user) {
int status = 0;
try {
Connection con = DbConnection.getConnection();
PreparedStatement ps = con.prepareStatement("INSERT INTO users (name, password, email, country) VALUES (?, ?, ?, ?)");
ps.setString(1, user.getName());
ps.setString(2, user.getPassword());
ps.setString(3, user.getEmail());
ps.setString(4, user.getCountry());
status = ps.executeUpdate();
con.close();
}catch(Exception ex) {
ex.printStackTrace();
}
return status;
}
public static int updateTime(String email, String timestamp) {
int status = 0;
try {
Connection con = DbConnection.getConnection();
PreparedStatement ps = con.prepareStatement("UPDATE users SET timestamp = ? WHERE email = ?");
ps.setString(1, timestamp);
ps.setString(2, email);
status = ps.executeUpdate();
con.close();
}catch(Exception ex) {
ex.printStackTrace();
}
return status;
}
The problem is when I click the Button I see it is getting stuck while running that process. So I put that code inside the following,
Platform.runLater(() -> {
try {
} catch (Exception ex) {
Exceptions.printStackTrace(ex);
}
});
Now it is somewhat okay but I see it is getting a little stuck after clicking (Ripple effect is not working well and also the mouse hover effect is not working as usual).
And Email Validation is done when the user types an email in the text field and the key released event is triggered and it is checking for the database result. The code for checking email is as follows,
public static boolean emailAvailability(String email) {
boolean status = false;
try {
Connection con = DbConnection.getConnection();
PreparedStatement ps = con.prepareStatement("SELECT email FROM users WHERE email = ?");
ps.setString(1, email);
ResultSet rs = ps.executeQuery();
status = rs.next();
con.close();
}catch(Exception ex) {
ex.printStackTrace();
}
return status;
}
In the key event also it is getting stuck more. Can't type a character for some milliseconds.
I don't see any issue with my code because I have done this many times with Java Swing and all are perfectly working fine in Swing. And if a button is getting stuck with the running process I just put those codes inside the following and it works perfect,
new Thread(new Runnable() {
public void run() {
}
}).start();
I am not going to or trying to compare Java Swing and JavaFX But I need to know why JavaFX is behaving like this? What should I do to avoid this and run the program smoothly with the CSS effects if it is a huge process or not? Really appreciate it if anybody can help me. Thanks in advance.
UPDATE
Here is my signUp code. Executes when button clicks,
private void signUp(ActionEvent event) {
if (name.getText.equals("") && name.getText().isEmpty()) {
if (!name.getStyleClass().contains("error-class")) {
name.getStyleClass().add("error-class");
nameImageValidation.setImage(new Image("danger.png"));
nameImageValidation.setVisible(true);
}
} else {
name.getStyleClass().removeIf(style -> style.equals("error-class"));
nameImageValidation.setVisible(false);
}
if (password.getText.equals("") && password.getText().isEmpty()) {
if (!password.getStyleClass().contains("error-class")) {
password.getStyleClass().add("error-class");
passwordImageValidation.setImage(new Image("danger.png"));
passwordImageValidation.setVisible(false);
}
} else {
password.getStyleClass().removeIf(style -> style.equals("error-class"));
passwordImageValidation.setVisible(false);
}
if (email.getText.equals("") && email.getText().isEmpty()) {
if (!email.getStyleClass().contains("error-class")) {
email.getStyleClass().add("error-class");
emailImageValidation.setImage(new Image("danger.png"));
emailImageValidation.setVisible(false);
}
} else {
email.getStyleClass().removeIf(style -> style.equals("error-class"));
emailImageValidation.setVisible(false);
}
if (country.getText.equals("") && country.getText().isEmpty()) {
if (!country.getStyleClass().contains("error-class")) {
country.getStyleClass().add("error-class");
countryImageValidation.setImage(new Image("danger.png"));
countryImageValidation.setVisible(false);
}
} else {
country.getStyleClass().removeIf(style -> style.equals("error-class"));
countryImageValidation.setVisible(false);
}
if(emailValidation() && passwordValidation() && fieldsValidation()) {
User user = new User(name.getText(), email.getText(), password.getText(), country.getText());
int insertStatus = UserController.insertUser(user);
Timestamp timestamp = new Timestamp(System.currentTimeMillis());
if (insertStatus > 0) {
int updateStatus = UserController.updateTime(email.getText(), timestamp.toString());
if(updateStatus > 0) {
// Go to Login Page
} else {
showAlert(); // Error Message
}
} else {
showAlert(); // Error Message
}
} else {
showAlert(); // Error Message
}
}
Here the validateEmail code. Executes when user typing the email. Triggered when Key Released and when performing this after type a character have to wait some time and then appear next character and go...
private void validateEmail(KeyEvent event) {
boolean status = UserController.emailAvailability(email.getText());
if (!status) {
email.getStyleClass().removeIf(style -> style.equals("success-class"));
emailImageValidation.setImage(new Image("safe.png"));
emailImageValidation.setVisible(true);
} else {
email.getStyleClass().removeIf(style -> style.equals("error-class"));
emailImageValidation.setImage(new Image("danger.png"));
emailImageValidation.setVisible(true);
}
}

Answer 1

When you trigger a function from the GUI, execution happens in the main thread. Now, these calls are blocking, which means that until they return, the main thread can't update the GUI.
There are generally two ways to solve this:
Async functions, that yield (allows other code to run) until the resource they are waiting for become available
Threads, which means running part of the program in parrallel, which most likely will require you to think about locks etc.
I suggest you look into these two things, as they are quite central to making good apps that are connected to other services and IO