import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;


/**
 * Servlet Filter implementation class TestFilter
 */
public class TestFilter implements Filter {
	
	class CustomRequest extends HttpServletRequestWrapper {

		HttpServletRequest request;
		
		public CustomRequest(HttpServletRequest request) {
			super(request);
			this.request = request;
		}

		
		@Override
		public String getRemoteAddr() {
			String header = request.getHeader("x-forwarded-for"); 
			if ( header != null) {
				return header;
			} else {
				return request.getRemoteAddr();
			}
		}

		@Override
		public String getRemoteHost() {
			return getRemoteAddr();
		}

		
	}

    /**
     * Default constructor. 
     */
    public TestFilter() {
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see Filter#destroy()
	 */
	public void destroy() {
		// TODO Auto-generated method stub
	}

	/**
	 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
	 */
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {

		HttpServletRequest req = (HttpServletRequest) request;
		
		chain.doFilter(new CustomRequest(req), response);
	}

	/**
	 * @see Filter#init(FilterConfig)
	 */
	public void init(FilterConfig fConfig) throws ServletException {
		// TODO Auto-generated method stub
	}

}