private String createUserAgentString() {
            // Mozilla/5.0 (compatible; mycrawler/1.0; +http://www.mydomain.com;
            // mycrawler@mydomain.com)
            StringBuilder sb = new StringBuilder();
            sb.append(_browserVersion);
            sb.append(" (compatible; ");
            sb.append(_agentName);
            sb.append("/");
            sb.append(_crawlerVersion);
            if (_webAddress != null && !_webAddress.isEmpty()) {
                sb.append("; +");
                sb.append(_webAddress);
            }
            if (_emailAddress != null && !_emailAddress.isEmpty()) {
                if(_webAddress == null || _webAddress.isEmpty()) {
                    sb.append(";");
                }
                sb.append(" ");
                sb.append(_emailAddress);
            }
            sb.append(")");
            return sb.toString();
        }
Creates a string representing the user agent characteristics.

@return User Agent String
crawler-commons/src/main/java/achecrawler/crawler/crawlercommons/fetcher/http/UserAgent.java