code: protected String getString(Exchange exchange, Message message, String name) {
          Object value = getObject(exchange, message, name);
          if (value instanceof String) {
              return (String)value;
          } else if (value != null) {
              return String.valueOf(value);
          }
          return null;
      }
docs: Gets a String context property.
  
  @param exchange the exchange
  @param message the message
  @param name the name
  @return the property