code: private String getParameter(Map<String, String> params, String key, String defaultValue) {
  
          String value = params.get(key);
          return (value != null) ? value : defaultValue;
      }
docs: Returns a parameter value from the module parameters,
  or a given default value in case the parameter is not set.<p>
  
  @param params the parameter map to get a value from
  @param key the parameter to return the value for
  @param defaultValue the default value in case there is no value stored for this key
  
  @return the parameter value from the module parameters