code: static public String generateKey(HttpServletRequest request, Iterable<ICacheKeyGenerator> keyGens) {
  		StringBuffer sb = new StringBuffer();
  		for (ICacheKeyGenerator keyGen : keyGens) {
  			String key = keyGen.generateKey(request);
  			if (key != null && key.length() > 0) {
  				sb.append(sb.length() > 0 ? ";" : "").append(key); //$NON-NLS-1$ //$NON-NLS-2$
  			}
  		}
  		return sb.toString();
  	}
docs: Generates a cache key by aggregating (concatenating) the output of
  each of the cache key generators in the array.
  
  @param request The request object
  @param keyGens The array
  @return The aggregated cache key