Switching authentication approaches at runtime with Spring Security?

Question

Typically, when you declare different "<authentication-provider>" for your application (webapp in my case), Spring Security takes care of invoking providers one after another, incase of failure. So, say I have DatabaseAuthenticationProvider and LDAPAuthenticationProvider with DatabaseAuthenticationProvider declared first in the config file, at runtime, DatabaseAuthenticationProvider is invoked first and if authentication fails, LDAPAuthentication is tried. This is cool - However, what I need is a runtime switch.

I would like to have an option of chosing between these two approaches (database based authentication / ldap based authentication) and somehow swith the implementation based on thsi global setting.

How do I do it? Is it even possible with Spring-Security?

Answer 1

How about writing a delegating AuthenticationProvider that knows how to access your runtime switch and the actual instances of Database/LDAP AuthenticationProvider.

I'm thinking of something like:

public class SwitchingAuthenticationProvider implements AuthenticationProvider
{
    private List<AuthenticationProvider> delegateList;
    private int selectedProvider;

    @Override
    public Authentication authenticate(Authentication authentication)
        throws AuthenticationException
    {
        AuthenticationProvider delegateTo = delegateList.get(selectedProvider);
        return delegateTo.authenticate(authentication);
    }

    ....
}