taglibs/src/main/java/org/springframework/security/taglibs/authz/AbstractAuthorizeTag.java
protected EvaluationContext createExpressionEvaluationContext(
			SecurityExpressionHandler<FilterInvocation> handler) {
		FilterInvocation f = new FilterInvocation(getRequest(), getResponse(),
				new FilterChain() {
					public void doFilter(ServletRequest request, ServletResponse response)
							throws IOException, ServletException {
						throw new UnsupportedOperationException();
					}
				});

		return handler.createEvaluationContext(SecurityContextHolder.getContext()
				.getAuthentication(), f);
	}
protected EvaluationContext createExpressionEvaluationContext(
			SecurityExpressionHandler<FilterInvocation> handler) {
		FilterInvocation f = new FilterInvocation(getRequest(), getResponse(),
				new FilterChain() {
					public void doFilter(ServletRequest request, ServletResponse response)
							throws IOException, ServletException {
						throw new UnsupportedOperationException();
					}
				});

		return handler.createEvaluationContext(SecurityContextHolder.getContext()
				.getAuthentication(), f);
	}
Allows the {@code EvaluationContext} to be customized for variable lookup etc.