1. import java.time.LocalDate;
  2. import java.time.LocalTime;
  3. import java.time.ZoneId;
  4. import java.time.format.DateTimeFormatter;
  5. import java.time.format.DateTimeParseException;
  7. class TimeValidator {
  9. /**
  10. * Validates a time string, handling potential errors and ensuring backward compatibility.
  11. * @param timeString The time string to validate.
  12. * @param expectedFormat The expected format of the time string.
  13. * @return A LocalTime object if the time string is valid, otherwise null.
  14. */
  15. public static LocalTime validateTime(String timeString, String expectedFormat) {
  16. try {
  17. // Use DateTimeFormatter to parse the time string.
  18. DateTimeFormatter formatter = DateTimeFormatter.ofPattern(expectedFormat);
  19. LocalTime time = LocalTime.parse(timeString, formatter);
  20. return time;
  21. } catch (DateTimeParseException e) {
  22. // Handle parsing errors (invalid time format).
  23. System.err.println("Error: Invalid time format. Expected: " + expectedFormat + ", Actual: " + timeString);
  24. return null;
  25. } catch (NullPointerException e) {
  26. // Handle null input.
  27. System.err.println("Error: Time string cannot be null.");
  28. return null;
  29. }
  30. }
  32. /**
  33. * Validates a date and time string, handling potential errors and ensuring backward compatibility.
  34. * @param dateTimeString The date and time string to validate.
  35. * @param expectedFormat The expected format of the date and time string.
  36. * @return A LocalDate object if the date and time string is valid, otherwise null.
  37. */
  38. public static LocalDate validateDateTime(String dateTimeString, String expectedFormat) {
  39. try {
  40. DateTimeFormatter formatter = DateTimeFormatter.ofPattern(expectedFormat);
  41. LocalDate date = LocalDate.parse(dateTimeString, formatter);
  42. return date;
  43. } catch (DateTimeParseException e) {
  44. System.err.println("Error: Invalid date/time format. Expected: " + expectedFormat + ", Actual: " + dateTimeString);
  45. return null;
  46. } catch (NullPointerException e) {
  47. System.err.println("Error: Date/time string cannot be null.");
  48. return null;
  49. }
  50. }
  52. public static void main(String[] args) {
  53. // Example Usage
  54. String timeStr1 = "14:30";
  55. String timeStr2 = "invalid_time";
  56. String dateTimeStr1 = "2024-01-01 14:30";
  57. String dateTimeStr2 = "invalid date";
  58. String dateTimeStr3 = null;
  60. LocalTime time1 = validateTime(timeStr1, "HH:mm");
  61. LocalTime time2 = validateTime(timeStr2, "HH:mm");
  62. LocalDate date1 = validateDateTime(dateTimeStr1, "yyyy-MM-dd HH:mm");
  63. LocalDate date2 = validateDateTime(dateTimeStr2, "yyyy-MM-dd HH:mm");
  64. LocalDate date3 = validateDateTime(dateTimeStr3, "yyyy-MM-dd HH:mm");
  66. if (time1 != null) {
  67. System.out.println("Valid Time: " + time1);
  68. }
  69. if (time2 == null) {
  70. System.out.println("Invalid Time: " + time2);
  71. }
  72. if (date1 != null) {
  73. System.out.println("Valid Date: " + date1);
  74. }
  75. if (date2 == null) {
  76. System.out.println("Invalid Date: " + date2);
  77. }
  78. if(date3 == null) {
  79. System.out.println("Invalid Date: " + date3);
  80. }
  81. }
  82. }

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