public String params(String param) {
        if (param == null) {
            return null;
        }

        if (param.startsWith(":")) {
            return params.get(param.toLowerCase()); // NOSONAR
        } else {
            return params.get(":" + param.toLowerCase()); // NOSONAR
        }
    }
Returns the value of the provided route pattern parameter.
Example: parameter 'name' from the following pattern: (get '/hello/:name')

@param param the param
@return null if the given param is null or not found
src/main/java/spark/Request.java