Stop Authenticated Users From Accessing Login Processing URL - Spring Security - spring

Question

I'm creating a web app that will be run on a single page. For this reason, I need to have my authentication paths accessible using only Ajax calls (no redirection).
I'm using Spring Security and I have the login and logout functionality working fine so far. The issue is that when the user is already authenticated and they POST to the login-processing-url they are actually logged in again. What I want to happen is my jsonAuthenticationHandler or some other handler to return a 500 or something telling me I can't log in again.
Here's what I've got for my security XML:
<sec:http use-expressions="true" entry-point-ref="jsonAuthenticationHandler">
<sec:intercept-url pattern="/data/**" access="isAuthenticated()"/>
<sec:intercept-url pattern="/data/login" access="!isAuthenticated()"/> <!--This is the line that is not behaving as expected-->
<sec:form-login login-page="/data/loginpage"
login-processing-url="/data/login"
username-parameter="username"
password-parameter="password"
authentication-failure-handler-ref="authenticationFailureHandler"
authentication-success-handler-ref="authenticationSuccessHandler"/>
<sec:logout logout-url="/data/logout"
delete-cookies="true"
invalidate-session="true"
logout-success-url="/"/>
</sec:http>
<bean id="jsonAuthenticationHandler" class="com.example.security.JsonAuthenticationHandler">
<constructor-arg name="loginUrl" value="/data/loginpage"/>
</bean>
<bean id="userDetailsService" class="com.example.security.UserDetailService"/>
<bean id="encoder" class="org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder"/>
<bean id="authenticationSuccessHandler" class="com.example.security.AuthenticationSuccessHandler"/>
<bean id="authenticationFailureHandler" class="com.example.security.AuthenticationFailureHandler"/>
<sec:authentication-manager>
<sec:authentication-provider user-service-ref="userDetailsService">
<sec:password-encoder ref="encoder"/>
</sec:authentication-provider>
</sec:authentication-manager>
Thanks in advance for any help!

Answer 1

Assuming you have a form to login you can simple hide it after successful Ajax post or you can use security taglib
<sec:authorize access="isAnonymous()">
<!-- you form here -->
</sec:authorize>
It will render when there is no user logged in, but when you log you can make a call to render again the view, then the content of these tags will disappear because now the user is authenticated.
These tags render the content based on what role or status of authentication.
Maven dependency:
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-taglibs</artifactId>
<version>3.2.4.RELEASE</version>
</dependency>