@Override
    public void registerAuthenticationPreProcessor(final AuthenticationPreProcessor processor) {
        if (BeanSupplier.isNotProxy(processor)) {
            LOGGER.debug("Registering authentication pre processor [{}] into the execution plan", processor);
            authenticationPreProcessors.add(processor);
        }
    }
This is {@link DefaultAuthenticationEventExecutionPlan}.

@author Misagh Moayyed
@since 5.1.0
core/cas-server-core-authentication-api/src/main/java/org/apereo/cas/authentication/DefaultAuthenticationEventExecutionPlan.java