code: public String getCacheKey(String name, Tree params, String... keys) {
  		if (params == null) {
  			return name;
  		}
  		StringBuilder key = new StringBuilder(128);
  		key.append(name);
  		key.append(':');
  		serializeKey(key, params, keys);
  		return key.toString();
  	}
docs: Creates a cacher-specific key by name and params. Concatenates the name
  and params.
  
  @param name
  qualified name of the action
  @param params
  input (key) structure (~JSON)
  @param keys
  optional array of keys (eg. "id")
  
  @return generated cache key