code: private Collection<String> getEIPsFromServiceUrls(List<String> ec2Urls) {
          List<String> returnedUrls = new ArrayList<String>();
          String region = clientConfig.getRegion();
          String regionPhrase = "";
          if (!US_EAST_1.equals(region)) {
              regionPhrase = "." + region;
          }
          for (String cname : ec2Urls) {
              int beginIndex = cname.indexOf("ec2-");
  
              if (-1 < beginIndex) {
                  // CNAME contains "ec2-"
                  int endIndex = cname.indexOf(regionPhrase + ".compute");
                  String eipStr = cname.substring(beginIndex + 4, endIndex);
                  String eip = eipStr.replaceAll("\\-", ".");
                  returnedUrls.add(eip);
              }
              
              // Otherwise, if CNAME doesn't contain, do nothing.
              // Handle case where there are no cnames containing "ec2-". Reasons include:
              //  Systems without public addresses - purely attached to corp lan via AWS Direct Connect
              //  Use of EC2 network adapters that are attached to an instance after startup
          }
          return returnedUrls;
      }
docs: Get the list of EIPs from the ec2 urls.
  
  @param ec2Urls
  the ec2urls for which the EIP needs to be obtained.
  @return collection of EIPs.