code: public void setTrustedProxies(String trustedProxies) {
          if (trustedProxies == null || trustedProxies.length() == 0) {
              this.trustedProxies = null;
          } else {
              this.trustedProxies = Pattern.compile(trustedProxies);
          }
      }
docs: <p>
  Regular expression defining proxies that are trusted when they appear in
  the {@link #remoteIpHeader} header.
  </p>
  <p>
  Default value : empty list, no external proxy is trusted.
  </p>