1. import java.util.ArrayList;
  2. import java.util.HashMap;
  3. import java.util.List;
  4. import java.util.Map;
  6. public class HeaderMetadataPaginator {
  8. private final List<HeaderMetadata> headerMetadataList;
  9. private final int pageSize;
  11. public HeaderMetadataPaginator(List<HeaderMetadata> headerMetadataList, int pageSize) {
  12. this.headerMetadataList = headerMetadataList;
  13. this.pageSize = pageSize;
  14. }
  16. public List<HeaderMetadata> getPage(int pageNumber) {
  17. // Calculate the starting index for the current page.
  18. int startIndex = (pageNumber - 1) * pageSize;
  20. // Ensure the starting index is within the bounds of the list.
  21. if (startIndex >= headerMetadataList.size()) {
  22. return new ArrayList<>(); // Return an empty list if the page is out of bounds.
  23. }
  25. // Create a sublist representing the current page.
  26. List<HeaderMetadata> page = headerMetadataList.subList(startIndex, Math.min(startIndex + pageSize, headerMetadataList.size()));
  27. return page;
  28. }
  30. public int getTotalPages() {
  31. // Calculate the total number of pages.
  32. return (int) Math.ceil((double) headerMetadataList.size() / pageSize);
  33. }
  35. // Inner class to represent header metadata.
  36. public static class HeaderMetadata {
  37. private String headerName;
  38. private String headerValue;
  40. public HeaderMetadata(String headerName, String headerValue) {
  41. this.headerName = headerName;
  42. this.headerValue = headerValue;
  43. }
  45. public String getHeaderName() {
  46. return headerName;
  47. }
  49. public String getHeaderValue() {
  50. return headerValue;
  51. }
  52. }
  54. public static void main(String[] args) {
  55. // Example Usage
  56. List<HeaderMetadata> allMetadata = new ArrayList<>();
  57. allMetadata.add(new HeaderMetadata("timestamp", "2024-01-01T10:00:00Z"));
  58. allMetadata.add(new HeaderMetadata("task_id", "12345"));
  59. allMetadata.add(new HeaderMetadata("status", "completed"));
  60. allMetadata.add(new HeaderMetadata("user_id", "user123"));
  61. allMetadata.add(new HeaderMetadata("data", "{\"key\": \"value\"}"));
  62. allMetadata.add(new HeaderMetadata("priority", "high"));
  63. allMetadata.add(new HeaderMetadata("environment", "production"));
  64. allMetadata.add(new HeaderMetadata("version", "1.0"));
  65. allMetadata.add(new HeaderMetadata("log_level", "INFO"));
  66. allMetadata.add(new HeaderMetadata("memory_usage", "1024MB"));
  69. HeaderMetadataPaginator paginator = new HeaderMetadataPaginator(allMetadata, 3);
  71. // Get the first page.
  72. List<HeaderMetadata> page1 = paginator.getPage(1);
  73. System.out.println("Page 1:");
  74. for (HeaderMetadata metadata : page1) {
  75. System.out.println(" " + metadata.getHeaderName() + ": " + metadata.getHeaderValue());
  76. }
  78. // Get the second page.
  79. List<HeaderMetadata> page2 = paginator.getPage(2);
  80. System.out.println("\nPage 2:");
  81. for (HeaderMetadata metadata : page2) {
  82. System.out.println(" " + metadata.getHeaderName() + ": " + metadata.getHeaderValue());
  83. }
  85. //Get the last page
  86. List<HeaderMetadata> page3 = paginator.getPage(3);
  87. System.out.println("\nPage 3:");
  88. for (HeaderMetadata metadata : page3) {
  89. System.out.println(" " + metadata.getHeaderName() + ": " + metadata.getHeaderValue());
  90. }
  92. //Get the total number of pages
  93. System.out.println("\nTotal pages: " + paginator.getTotalPages());
  94. }
  95. }

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