code: public void validate(String path, Schema schema, Object value, List<ValidationResult> results) {
  		if (_rules == null)
  			return;
  
  		for (IValidationRule rule : _rules)
  			rule.validate(path, schema, value, results);
  	}
docs: Validates a given value against this rule.
  
  @param path    a dot notation path to the value.
  @param schema  a schema this rule is called from
  @param value   a value to be validated.
  @param results a list with validation results to add new results.