1. import java.io.IOException;
  2. import java.util.concurrent.TimeoutException;
  4. public class MetadataWrapper {
  6. /**
  7. * Wraps a metadata operation with a timeout mechanism to handle potential errors.
  8. * @param metadataOperation The operation to perform on metadata.
  9. * @param timeoutMillis The timeout duration in milliseconds.
  10. * @return The result of the metadata operation, or null if an error occurs.
  11. * @throws IOException If an I/O error occurs during the metadata operation.
  12. * @throws TimeoutException If the metadata operation exceeds the timeout duration.
  13. */
  14. public static <T> T executeMetadataOperation(MetadataOperation<T> metadataOperation, long timeoutMillis) throws IOException, TimeoutException {
  15. try {
  16. // Execute the metadata operation with a timeout.
  17. return metadataOperation.execute(timeoutMillis);
  18. } catch (IOException e) {
  19. // Wrap the IOException with a custom metadata error.
  20. throw new MetadataError("Error accessing metadata", e);
  21. } catch (TimeoutException e) {
  22. // Wrap the TimeoutException with a custom metadata error.
  23. throw new MetadataError("Metadata operation timed out", e);
  24. }
  25. }
  27. /**
  28. * Custom exception to represent errors related to metadata operations.
  29. */
  30. public static class MetadataError extends Exception {
  31. public MetadataError(String message, Throwable cause) {
  32. super(message, cause);
  33. }
  34. }
  36. /**
  37. * Functional interface representing a metadata operation.
  38. * @param <T> The type of the result.
  39. */
  40. public interface MetadataOperation<T> {
  41. T execute(long timeoutMillis) throws IOException, TimeoutException;
  42. }
  44. public static void main(String[] args) throws IOException, TimeoutException {
  45. // Example Usage:
  47. // Define a dummy metadata operation.
  48. MetadataOperation<String> dummyOperation = (timeout) -> {
  49. try {
  50. // Simulate a long-running operation.
  51. Thread.sleep(2000);
  52. return "Metadata data";
  53. } catch (InterruptedException e) {
  54. Thread.currentThread().interrupt();
  55. throw new IOException("Interrupted during metadata operation", e);
  56. }
  57. };
  59. try {
  60. // Execute the metadata operation with a timeout of 1 second.
  61. String metadata = executeMetadataOperation(dummyOperation, 1000);
  62. System.out.println("Metadata: " + metadata);
  63. } catch (MetadataError e) {
  64. System.err.println("Metadata Error: " + e.getMessage());
  65. } catch (IOException e) {
  66. System.err.println("IO Error: " + e.getMessage());
  67. } catch (TimeoutException e) {
  68. System.err.println("Timeout Error: " + e.getMessage());
  69. }
  71. //Example with a failing operation
  73. MetadataOperation<String> failingOperation = (timeout) -> {
  74. throw new IOException("Simulated metadata error");
  75. };
  77. try {
  78. String metadata = executeMetadataOperation(failingOperation, 1000);
  79. System.out.println("Metadata: " + metadata);
  80. } catch (MetadataError e) {
  81. System.err.println("Metadata Error: " + e.getMessage());
  82. } catch (IOException e) {
  83. System.err.println("IO Error: " + e.getMessage());
  84. } catch (TimeoutException e) {
  85. System.err.println("Timeout Error: " + e.getMessage());
  86. }
  87. }
  88. }

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