Builder pattern example, Validator class

gistfile1.txt

class Validator {
    private Set<String> validationErrors;
    private Map<String[], ValidationRule> validationRules;
    private boolean validated = false;

    Validator() {
      validationRules = new HashMap<String[], ValidationRule>();
      validationErrors = new HashSet<String>();
    }

    public void addValidationRule(ValidationRule newValidationRule, String... args) {
      String[] argsAsArray = args;
      validationRules.put(argsAsArray, newValidationRule);
    }

    public void validate() {
      for(Map.Entry<String[], ValidationRule> entry : validationRules.entrySet()) {
        String[] valuesToValidate = entry.getKey();
        ValidationRule rule = entry.getValue();
        for(int i = 0; i < valuesToValidate.length; i++) {
          if(!rule.validate(valuesToValidate[i])) {
            validationErrors.add(rule.getErrorMessage());
          }
        }
      }
      validated = true;
    }

    public boolean hasValidationErrors() {
      if(!validated) {
        validate();
      }
      return validationErrors.size() > 0;
    }

    public String[] getValidationErrors() {
      if(!validated) {
        validate();
      }
      return validationErrors.toArray(new String[validationErrors.size()]);
    }
  }