code: public static void isNumeric(String parameter, String name) {
  		if (!Strings.isNumeric(parameter)) {
  			throw new IllegalArgumentException(String.format("%s |%s| is not numeric.", name, parameter));
  		}
  	}
docs: Check if string parameter is numeric. This validator throws illegal argument if parameter value is not numeric. See
  {@link Strings#isNumeric(String)} for <code>numeric</code> definition.
  
  @param parameter invocation parameter value,
  @param name parameter name.
  @throws IllegalArgumentException if <code>parameter</code> is not numeric.