public static Validator createListValidator()

in src/main/java/org/apache/nifi/processor/util/StandardValidators.java [542:573]
30 lines of code
12 McCabe index (conditional complexity)

    public static Validator createListValidator(boolean trimEntries, boolean excludeEmptyEntries,
                                                Validator validator,
                                                boolean ensureElementValidation) {
        return (subject, input, context) -> {
            if (context.isExpressionLanguageSupported(subject) && context.isExpressionLanguagePresent(input)) {
                return new ValidationResult.Builder().subject(subject).input(input).explanation("Expression Language Present").valid(true).build();
            }
            try {
                if (input == null) {
                    return new ValidationResult.Builder().subject(subject).input(null).explanation("List must have at least one non-empty element").valid(false).build();
                }

                final String[] list = ensureElementValidation ? input.split(",", -1) : input.split(",");
                if (list.length == 0) {
                    return new ValidationResult.Builder().subject(subject).input(null).explanation("List must have at least one non-empty element").valid(false).build();
                }

                for (String item : list) {
                    String itemToValidate = trimEntries ? item.trim() : item;
                    if (!isEmpty(itemToValidate) || !excludeEmptyEntries) {
                        ValidationResult result = validator.validate(subject, itemToValidate, context);
                        if (!result.isValid()) {
                            return result;
                        }
                    }
                }
                return new ValidationResult.Builder().subject(subject).input(input).explanation("Valid List").valid(true).build();
            } catch (final Exception e) {
                return new ValidationResult.Builder().subject(subject).input(input).explanation("Not a valid list").valid(false).build();
            }
        };
    }