1. import java.time.LocalDateTime;
  2. import java.time.format.DateTimeFormatter;
  3. import java.util.function.Consumer;
  5. class TimeValidator {
  7. /**
  8. * Wraps a function that validates a time value, handling potential errors with limited memory.
  9. *
  10. * @param validator A function that takes a LocalDateTime and returns true if valid, false otherwise.
  11. * @param errorMessage The error message to be associated with validation failures.
  12. * @return A validation wrapper that can be used to execute the validation function.
  13. */
  14. public static ValidationWrapper<LocalDateTime> wrapValidation(Consumer<LocalDateTime> validator, String errorMessage) {
  15. return new ValidationWrapper<>(validator, errorMessage);
  16. }
  19. /**
  20. * Represents a wrapped validation result, including the validation function and error message.
  21. */
  22. static class ValidationWrapper<T> {
  23. private final Consumer<T> validator;
  24. private final String errorMessage;
  26. ValidationWrapper(Consumer<T> validator, String errorMessage) {
  27. this.validator = validator;
  28. this.errorMessage = errorMessage;
  29. }
  31. /**
  32. * Executes the validation function and handles any errors.
  33. *
  34. * @param time The time value to be validated.
  35. * @throws IllegalArgumentException if the validation function fails.
  36. */
  37. public void validate(LocalDateTime time) {
  38. try {
  39. validator.accept(time);
  40. } catch (Exception e) {
  41. throw new IllegalArgumentException(errorMessage + ": " + e.getMessage(), e); // Re-throw with context
  42. }
  43. }
  44. }
  46. public static void main(String[] args) {
  47. // Example usage
  48. ValidationWrapper<LocalDateTime> validator = TimeValidator.wrapValidation(time -> {
  49. if (time.isBefore(LocalDateTime.now())) {
  50. throw new IllegalArgumentException("Time cannot be in the past.");
  51. }
  52. // Add other validation rules here
  53. }, "Invalid time value");
  55. try {
  56. validator.validate(LocalDateTime.now().plusDays(1)); //Valid
  57. System.out.println("Validation successful");
  58. validator.validate(LocalDateTime.now().minusDays(1)); // Invalid - should throw exception
  59. } catch (IllegalArgumentException e) {
  60. System.err.println("Validation failed: " + e.getMessage());
  61. }
  62. }
  63. }

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