private static List < String > resolveValues ( final Iterable < ? extends String > values ) { final List < String > valuesList = new ArrayList < String > ( ) ; for ( final String value : values ) { Validate . notNull ( value , "One of the specified values was null" ) ; valuesList . add ( value ) ; } return valuesList ; }
Private helper method for setting the field values . nulls are not permitted . Instances are immutable so this method cannot be made public .