Java MessageFormat - best way to check incomplete format

Question

String[] params = new String[];
params[0] = "param0";

String pattern = "{2}, {1}, {0}"

String result = MessageFormat.format(pattern, params);

System.out.println(result);

Result:

{2}, {1}, param0

I want to throw an exception if the size of params array does not much the number of placeholders in pattern. What would be the best way to validate this?

MessageFormat format = new MessageFormat(pattern);
if (format.getFormats().length != params.size()) {
  throw new Exception("example");
}