Skip to main content

​
Overview

The Authentication component (Login.java) provides secure access control to the MatriculaUniPoo system. It validates user credentials against registration data and manages navigation between screens.

​
Component Architecture

​
Core Structure

The Login class maintains credential state and manages authentication flow:
Login.java
public class Login extends javax.swing.JFrame {
    private Registrar regis;
    private Matricula matri;
    private String regisDni;
    private String regisContra;

    public Login() {
        this("","");
        initComponents();
    }
    
    public Login(String regisDni, String regisContra) {
        this.regisDni = regisDni;
        this.regisContra = regisContra;
        this.matri = new Matricula();
        matri.setLog(this);
        initComponents();
    }
}
The component supports two constructors: a default empty constructor and one that receives credentials from the registration process.

​
User Interface Design

​
Dual Panel Layout

The login screen features a modern two-panel design: 
jPanel2.setBackground(new java.awt.Color(255, 255, 255));
jPanel2.setForeground(new java.awt.Color(0, 153, 255));

jLabel5.setIcon(new javax.swing.ImageIcon(
    "C:\\Users\\Anghelo\\Desktop\\CerebroLogin.png"
));
The left panel displays branding imagery while the right panel contains the login form.

​
Login Form Fields

1

Username Field

DNI (National ID) serves as the unique username
txtUsuario.setBackground(new java.awt.Color(0, 68, 68));
txtUsuario.setForeground(new java.awt.Color(255, 255, 255));
txtUsuario.setCaretColor(new java.awt.Color(255, 255, 255));
2

Password Field

Secure password field with masked input
pswContra.setBackground(new java.awt.Color(0, 68, 68));
pswContra.setForeground(new java.awt.Color(255, 255, 255));
pswContra.setCaretColor(new java.awt.Color(255, 255, 255));

​
Authentication Logic

​
Credential Validation

The login system performs exact matching of credentials:
Login.java:171-183
private void btnIniciarSesionActionPerformed(java.awt.event.ActionEvent evt) {
    String usuario = txtUsuario.getText();
    String contra = new String(pswContra.getPassword());
    
    if (usuario.equals(regisDni) && contra.equals(regisContra)) {
        JOptionPane.showMessageDialog(null, "INICIO EXITOSO");
        matri.setLog(this);
        matri.setVisible(true);
        matri.setLocationRelativeTo(null);
        this.setVisible(false);
    } else {
        JOptionPane.showMessageDialog(this, 
            "USUARIO O CONTRASEÑA INCORRECTA", 
            "Error", 
            JOptionPane.ERROR_MESSAGE);
    }
}
Both username (DNI) and password must match exactly for successful authentication. Partial matches are rejected.

​
Validation Flow

  1. Extract Credentials
    • Retrieve username from text field
    • Extract password from password field using getPassword()
  2. Compare Against Stored Values
    • Check if entered DNI matches regisDni
    • Verify password matches regisContra
  3. Success Path
    • Display success message dialog
    • Initialize Matricula (enrollment) component
    • Navigate to enrollment screen
    • Hide login window
  4. Failure Path
    • Show error dialog with descriptive message
    • Keep user on login screen
    • Allow retry without clearing fields

​
Security Considerations

​
Password Handling

The component uses JPasswordField for secure password entry: 
pswContra = new javax.swing.JPasswordField();
pswContra.setDisabledTextColor(new java.awt.Color(255, 255, 255));
pswContra.setSelectedTextColor(new java.awt.Color(255, 255, 255));
pswContra.setSelectionColor(new java.awt.Color(255, 255, 255));
JPasswordField automatically masks password characters as bullets (•) to prevent shoulder surfing.

​
Extracting Password Securely

Passwords are extracted using the recommended getPassword() method: 
String contra = new String(pswContra.getPassword());
This returns a char array instead of a String, allowing secure memory cleanup. The conversion to String happens only for comparison.

​
Return to Registration

Users can navigate back to registration if they don’t have an account:
Login.java:164-169
private void btnVolverActionPerformed(java.awt.event.ActionEvent evt) {
    regis.setLog(this);
    regis.setVisible(true);
    regis.setLocationRelativeTo(null);
    this.setVisible(false);
}

​
Session Flow

1

From Registration

After successful registration, credentials are passed to Login constructor
log = new Login(dni, contra);
log.setRegis(this);
log.setVisible(true);
2

Authentication

User enters credentials and attempts login
3

To Enrollment

Successful login navigates to Matricula (enrollment) screen
matri.setLog(this);
matri.setVisible(true);
matri.setLocationRelativeTo(null);

​
Component Interaction

​
Setter Methods for Navigation

The component provides setters to maintain references to other screens:
Login.java
public void setRegis(Registrar regis) {
    this.regis = regis;
}

public void setMatri(Matricula matri) {
    this.matri = matri;
}
These bidirectional references enable seamless navigation between components while preserving state.

​
User Feedback

​
Success Dialog

Successful authentication displays a confirmation message: 
JOptionPane.showMessageDialog(null, "INICIO EXITOSO");

​
Error Dialog

Failed authentication shows a descriptive error: 
JOptionPane.showMessageDialog(this, 
    "USUARIO O CONTRASEÑA INCORRECTA", 
    "Error", 
    JOptionPane.ERROR_MESSAGE);

Success Message

Generic success message without revealing which credential is correct

Error Message

Generic error that doesn’t specify which field is incorrect (security best practice)

​
Visual Styling

​
Form Labels

Clear, instructive labels guide users: 
jLabel1.setFont(new java.awt.Font("Segoe UI", 1, 14));
jLabel1.setForeground(new java.awt.Color(255, 255, 255));
jLabel1.setText("Ingresa tus datos para INICIAR SESION:");

jLabel3.setText("USUARIO: DNI DEL ESTUDIANTE");
jLabel4.setText("CONTRASEÑA");

​
Button Styling

Buttons follow the application’s color scheme: 
btnIniciarSesion.setBackground(new java.awt.Color(0, 153, 153));
btnIniciarSesion.setFont(new java.awt.Font("Segoe UI", 1, 14));
btnIniciarSesion.setForeground(new java.awt.Color(255, 255, 255));
btnIniciarSesion.setText("INICIAR SESION");

​
Layout Structure

​
Absolute Layout Configuration

The form uses absolute positioning for precise control: 
jPanel1.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());

jPanel1.add(txtUsuario, 
    new org.netbeans.lib.awtextra.AbsoluteConstraints(50, 130, 286, 30));
    
jPanel1.add(pswContra, 
    new org.netbeans.lib.awtextra.AbsoluteConstraints(50, 220, 286, 30));

​
Visual Separators

Separator lines organize the form visually: 
jSeparator1.setForeground(new java.awt.Color(255, 255, 255));
jPanel1.add(jSeparator1, 
    new org.netbeans.lib.awtextra.AbsoluteConstraints(6, 37, 330, 10));

jSeparator2.setForeground(new java.awt.Color(255, 255, 255));
jPanel1.add(jSeparator2, 
    new org.netbeans.lib.awtextra.AbsoluteConstraints(10, 160, 330, 10));

​
Key Features

Credential Matching

Exact string comparison for username and password validation

Secure Input

Password field masks sensitive data during entry

Navigation Control

Seamless transitions between registration, login, and enrollment

Error Handling

Clear feedback for authentication failures

Build docs developers (and LLMs) love

Get started for freeTalk to us