*
     * @param form the create form
     * @param username the current username
     * @param currentTime the current time
     * @return optional file authentication entity
     */
    public static OptionalEntity<FileAuthentication> getEntity(final CreateForm form, final String username, final long currentTime) {
        switch (form.crudMode) {
        case CrudMode.CREATE:

     * @param form the form containing the request header data
     * @param username the username of the user performing the operation
     * @param currentTime the current timestamp
     * @return optional entity containing the request header data, or empty if creation fails
     */
    public static OptionalEntity<RequestHeader> getEntity(final CreateForm form, final String username, final long currentTime) {
        switch (form.crudMode) {

		}
	}

	return nil
}

func (driver *ftpDriver) CheckPasswd(c *ftp.Context, username, password string) (ok bool, err error) {
	stopFn := globalFtpMetrics.log(c, username)
	defer stopFn(0, err)

	if globalIAMSys.LDAPConfig.Enabled() {
		sa, _, err := globalIAMSys.getServiceAccount(context.Background(), username)
		if err != nil && !errors.Is(err, errNoSuchServiceAccount) {
			return false, err
		}

                                    <label for="username" class="col-sm-3 text-sm-right col-form-label"><la:message
                                            key="labels.webauth_username"/></label>
                                    <div class="col-sm-9">
                                        <la:errors property="username"/>
                                        <la:text styleId="username" property="username" styleClass="form-control"/>

Betrachten wir es also aus dieser vereinfachten Sicht:

* Der Benutzer gibt den `username` und das `password` im Frontend ein und drückt `Enter`.
* Das Frontend (das im Browser des Benutzers läuft) sendet diesen `username` und das `password` an eine bestimmte URL in unserer API (deklariert mit `tokenUrl="token"`).
* Die API überprüft den `username` und das `password` und antwortet mit einem „Token“ (wir haben davon noch nichts implementiert).

							</c:if>
							<c:choose>
								<c:when test="${!empty username && username != 'guest'}">
									<li class="nav-item">
										<div class="dropdown">
											<a id="userMenu" class="nav-link dropdown-toggle" data-bs-toggle="dropdown"
												href="#" role="button" aria-haspopup="true"
												aria-expanded="false"> <em class="fa fa-fw fa-user">${username}
											</a>

    void delete(User user);

    /**
     * Changes the password for the specified user.
     * @param username The username for which to change the password.
     * @param password The new password.
     * @return True if the password was successfully changed, false otherwise.
     */
    boolean changePassword(String username, String password);

    /**
     * Loads user information from the authentication chain.

            }
            final int domainLength = domain != null ? domain.length : 0;
            final String userName = getUser();
            byte[] user = null;
            if (userName != null && userName.length() != 0) {
                user = unicode ? userName.getBytes(UNI_ENCODING) : userName.toUpperCase().getBytes(oem);
            }
            final int userLength = user != null ? user.length : 0;

Então, vamos rever de um ponto de vista simplificado:

* O usuário digita o `username` e a `senha` no frontend e aperta `Enter`.
* O frontend (rodando no browser do usuário) manda o `username` e a `senha` para uma URL específica na sua API (declarada com `tokenUrl="token"`).
* A API checa aquele `username` e `senha`, e responde com um "token" (nós não implementamos nada disso ainda).

				<la:form styleId="login" method="post">
					<div class="input-group mb-3">
						<c:set var="ph_username">
							<la:message key="labels.login.placeholder_username" />
						</c:set>
						<la:text property="username" styleId="username"
							class="form-control" placeholder="${ph_username}" />
						<div class="input-group-append">
							<span class="input-group-text">
								<em class="fa fa-user fa-fw">
            				</span>