Understanding the failedLogin() Method with Sequence Diagram

When a login attempt fails, the failedLogin() method is triggered to log the event. Let’s break it down step-by-step so even a fresher can understand:

Method Overview

public void failedLogin(RealmModel realm, UserModel user, ClientConnection clientConnection) {
    try {
        FailedLogin event = new FailedLogin(realm.getId(), user.getId(), clientConnection.getRemoteAddr());
        this.queue.offer(event);
        event.latch.await(5L, TimeUnit.SECONDS);
    } catch (InterruptedException var5) {
        // Interrupted while waiting
    }
    logger.trace("sent failure event");
}

Step-by-Step Explanation:

1. Trigger on Failed Login – Whenever a user enters the wrong credentials, this method is called.

2. Create a Failed Login Event – The FailedLogin object stores details such as:

   • realmId – The security domain in which the login failed.

   • userId – The user who failed to log in.

   • remoteAddress – The IP address from where the attempt was made.

3. Add to Event Queue – This event is placed into a queue for asynchronous processing.

4. Wait for Processing – The method waits up to 5 seconds for the event to be processed by a consumer.

5. Log the Event – It logs that the failure event was sent.

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Sequence Diagram

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Why Use This Approach?

• Asynchronous Processing – Avoids blocking the main login flow.

• Event-Driven – Other parts of the system can react to failed login events (e.g., account lockouts, alerts).

• Scalable – Handles many failed login events without slowing down the authentication server.