Validating Username Existence in Joget Forms via BeanShell

When users manually type a username into a Joget form field—such as assigning a person in charge, manager, or auditor—standard text inputs do not check if that username actually exists in Joget Directory Manager. If a user mistypes a username, the workflow will throw an error when trying to assign the subsequent activity.

In this guide, we'll write a custom BeanShell Form Validator script that checks dir_user in real time during form submission and displays an inline validation error if the entered username does not exist.

---

How It Works

1. Interpreting Input Values: The validator signature validate(Element element, FormData formData, String[] values) receives the user's input from the form field.
2. Directory Lookup: A parameterized SQL query (SELECT COUNT(*) FROM dir_user WHERE username = ?) checks the Joget Directory user database.
3. Form Error Injection: If the count is zero, formData.addFormError(elementId, errorMessage) marks the field as invalid and stops form submission.

---

The BeanShell Form Validator Script

Open your Joget Form in Form Builder, select the target Username field, set Validator to BeanShell Validator, and paste the script below:

import org.joget.apps.form.model.Element;
import org.joget.apps.form.model.FormData;
import org.joget.apps.form.service.FormUtil;
import org.joget.commons.util.LogUtil;
import org.joget.apps.app.service.AppUtil;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public boolean validateUsername(Element element, FormData formData, String[] values) {
    String elementId = FormUtil.getElementParameterName(element);

    // 1. Check for empty input
    if (values == null || values.length == 0 || values[0] == null || values[0].trim().isEmpty()) {
        formData.addFormError(elementId, "Username is required.");
        return false;
    }

    String inputUsername = values[0].trim();
    Connection con = null;
    PreparedStatement stmt = null;
    ResultSet rs = null;
    boolean userFound = false;

    try {
        // 2. Obtain DataSource and check Directory user table
        DataSource ds = (DataSource) AppUtil.getApplicationContext().getBean("setupDataSource");
        con = ds.getConnection();

        if (con != null && !con.isClosed()) {
            String sql = "SELECT COUNT(*) AS user_count FROM dir_user WHERE username = ?";
            stmt = con.prepareStatement(sql);
            stmt.setString(1, inputUsername);
            rs = stmt.executeQuery();

            if (rs.next() && rs.getInt("user_count") > 0) {
                userFound = true;
            }
        }

        // 3. Highlight field with inline error if user does not exist
        if (!userFound) {
            formData.addFormError(elementId, "User '" + inputUsername + "' does not exist in the system directory.");
        }

    } catch (Exception e) {
        LogUtil.error("Directory User Validator", e, "Database error during username validation");
        return false;
    } finally {
        if (rs != null) try { rs.close(); } catch (Exception e) {}
        if (stmt != null) try { stmt.close(); } catch (Exception e) {}
        if (con != null) try { con.close(); } catch (Exception e) {}
    }

    return userFound;
}

// Execute validation
return validateUsername(element, formData, values);

---

Alternative: Using DirectoryManager API

You can also perform the user lookup using Joget's DirectoryManager API directly:

import org.joget.apps.app.service.AppUtil;
import org.joget.directory.model.User;
import org.joget.directory.model.service.DirectoryManager;

DirectoryManager dirManager = (DirectoryManager) AppUtil.getApplicationContext().getBean("directoryManager");
User user = dirManager.getUserByUsername(inputUsername);

if (user == null) {
    formData.addFormError(elementId, "Specified user was not found.");
    return false;
}
return true;

Pro Tip

Use the direct SQL validator for high-speed bulk form submissions, and dirManager.getUserByUsername() when you also need to check whether the user is currently active (user.getGroupList(), user.getRoleList()).