1. import java.time.Instant;
  2. import java.time.LocalDateTime;
  3. import java.time.ZoneId;
  4. import java.util.HashMap;
  5. import java.util.Map;
  7. public class TimestampHandler {
  9. private static final ZoneId DEFAULT_ZONE = ZoneId.systemDefault(); // Default timezone
  10. private static final LocalDateTime DEFAULT_TIMESTAMP = LocalDateTime.now(); // Default timestamp
  12. /**
  13. * Gets a timestamp, falling back to a default value if the provided timestamp is invalid.
  14. *
  15. * @param timestamp The timestamp to use. Can be null or invalid.
  16. * @return A valid LocalDateTime representing the timestamp, or the default if invalid.
  17. */
  18. public static LocalDateTime getTimestamp(LocalDateTime timestamp) {
  19. if (timestamp != null && timestamp.isBefore(DEFAULT_TIMESTAMP)) {
  20. return DEFAULT_TIMESTAMP; // Use default if timestamp is in the past
  21. }
  22. return timestamp;
  23. }
  25. /**
  26. * Gets a timestamp from an Instant, falling back to a default value if the Instant is invalid.
  27. *
  28. * @param instant The instant to use. Can be null or invalid.
  29. * @return A valid LocalDateTime representing the timestamp, or the default if invalid.
  30. */
  31. public static LocalDateTime getTimestamp(Instant instant) {
  32. if (instant == null || instant.isBefore(DEFAULT_TIMESTAMP)) {
  33. return DEFAULT_TIMESTAMP; // Use default if instant is in the past
  34. }
  36. return LocalDateTime.ofInstant(instant, DEFAULT_ZONE);
  37. }
  39. /**
  40. * Handles a map of experiment results, providing default timestamps for any missing or invalid timestamps.
  41. *
  42. * @param results A map where keys are experiment identifiers and values are experiment results,
  43. * potentially containing a timestamp.
  44. * @return A map with the same keys, but with valid LocalDateTime timestamps for all entries.
  45. */
  46. public static Map<String, LocalDateTime> processExperimentResults(Map<String, ExperimentResult> results) {
  47. Map<String, LocalDateTime> processedResults = new HashMap<>();
  48. for (Map.Entry<String, ExperimentResult> entry : results.entrySet()) {
  49. String key = entry.getKey();
  50. ExperimentResult result = entry.getValue();
  52. LocalDateTime timestamp = result.getTimestamp();
  53. processedResults.put(key, getTimestamp(timestamp));
  54. }
  55. return processedResults;
  56. }
  58. // Example inner class to represent an experiment result.
  59. public static class ExperimentResult {
  60. private LocalDateTime timestamp;
  62. public ExperimentResult(LocalDateTime timestamp) {
  63. this.timestamp = timestamp;
  64. }
  66. public LocalDateTime getTimestamp() {
  67. return timestamp;
  68. }
  69. }
  71. public static void main(String[] args) {
  72. // Example Usage
  73. Map<String, ExperimentResult> experimentData = new HashMap<>();
  74. experimentData.put("experiment1", new ExperimentResult(LocalDateTime.now()));
  75. experimentData.put("experiment2", new ExperimentResult(null)); // Invalid timestamp
  76. experimentData.put("experiment3", new ExperimentResult(LocalDateTime.now().minusDays(1))); // Past timestamp
  77. experimentData.put("experiment4", new ExperimentResult(Instant.now()));
  79. Map<String, LocalDateTime> processedData = processExperimentResults(experimentData);
  81. for (Map.Entry<String, LocalDateTime> entry : processedData.entrySet()) {
  82. System.out.println("Experiment: " + entry.getKey() + ", Timestamp: " + entry.getValue());
  83. }
  84. }
  85. }

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