web/src/main/java/org/springframework/security/web/access/intercept/FilterSecurityInterceptor.java
public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);
	}
public void doFilter(ServletRequest request, ServletResponse response,
			FilterChain chain) throws IOException, ServletException {
		FilterInvocation fi = new FilterInvocation(request, response, chain);
		invoke(fi);
	}
Method that is actually called by the filter chain. Simply delegates to the
{@link #invoke(FilterInvocation)} method.

@param request the servlet request
@param response the servlet response
@param chain the filter chain

@throws IOException if the filter chain fails
@throws ServletException if the filter chain fails