Get remote IP from HttpServletRequest

HttpHeader.java

public enum HttpHeader {
    AUTHORIZATION("Authorization"),
    AUTHENTICATION_TYPE_BASIC("Basic"),
    X_AUTH_TOKEN("X-AUTH-TOKEN"),
    WWW_Authenticate("WWW-Authenticate"),
    X_FORWARDED_FOR("X-Forwarded-For"),
    PROXY_CLIENT_IP("Proxy-Client-IP"),
    WL_PROXY_CLIENT_IP("WL-Proxy-Client-IP"),
    HTTP_CLIENT_IP("HTTP_CLIENT_IP"),
    HTTP_X_FORWARDED_FOR("HTTP_X_FORWARDED_FOR");

    private String key;

    private HttpHeader(String key) {
        this.key = key;
    }

    public String key() {
        return this.key;
    }
}

RemoteIpHelper.java

import javax.servlet.http.HttpServletRequest;

import static ch.exq.triplog.server.util.http.HttpHeader.*;

public class RemoteIpHelper {

    private static final String UNKNOWN = "unknown";

    public static String getRemoteIpFrom(HttpServletRequest request) {
        String ip = null;
        int tryCount = 1;

        while (!isIpFound(ip) && tryCount <= 6) {
            switch (tryCount) {
                case 1:
                    ip = request.getHeader(X_FORWARDED_FOR.key());
                    break;
                case 2:
                    ip = request.getHeader(PROXY_CLIENT_IP.key());
                    break;
                case 3:
                    ip = request.getHeader(WL_PROXY_CLIENT_IP.key());
                    break;
                case 4:
                    ip = request.getHeader(HTTP_CLIENT_IP.key());
                    break;
                case 5:
                    ip = request.getHeader(HTTP_X_FORWARDED_FOR.key());
                    break;
                default:
                    ip = request.getRemoteAddr();
            }

            tryCount++;
        }

        return ip;
    }

    private static boolean isIpFound(String ip) {
        return ip != null && ip.length() > 0 && !UNKNOWN.equalsIgnoreCase(ip);
    }
}