Polish up your JFace-Viewer! Sorting a table by Tom Seidel 表格排序

http://www.javawiki.org/2006_01_18/tidy-up-your-jface-viewer-sorting-a-table/

Today I want to show how to add a sorter to your JFace-Table. The requirement is to sort descending und ascending by clicking on the TableColumn-Header.

The inital view with sorting

The ascending sorting after a click on the ID-Column header.

JFace already provides sorting-functionality. We just have to provide something like an alogrithm to arrange the items. For that we implemented the CollectionSorter that uses the default Collator from ViewerSorter. Now look at the Sorter:

Initializing the Sorter with a default column

PLAIN TEXT

JAVA:

1.  
2. public class CollationSorter extends ViewerSorter {
3.  
4. private Map sortMap = new HashMap ( );
5.  
6. /**
7. * Creates an instance of the sorter
8. * @param tc0 the default sorter-column.
9. */
10. public CollationSorter ( TableColumn defaultColumn ) {
11. setCurrentColumn (defaultColumn );
12. }
13.  
14. /**
15. * Pushs the current sortorder in a map which key is the
16. * table-column.
17. * @param column
18. */
19. public void pushSortCriteria ( TableColumn column ) {
20. if ( this. sortMap. get (column ) == null ) {
21. this. sortMap. put (column, new Boolean ( true ) );
22. }
23. else {
24. boolean newSort = ! ( ( Boolean ) this. sortMap. get (column ) ). booleanValue ( );
25. this. sortMap. put (column, new Boolean (newSort ) );
26. }
27. }
28.  
29. /**
30. * Asks for the current sort-order and inverts the sort-order
31. * @param column the requested column
32. * @return true if the sortIndex is descending, else false.
33. */
34. public boolean isDescending ( TableColumn column ) {
35. boolean returnValue = true;
36. if ( this. sortMap. get (column ) != null ) {
37. returnValue = ( ( Boolean ) this. sortMap. get (column ) ). booleanValue ( );
38. } else {
39. pushSortCriteria (column );
40. }
41. return returnValue;
42. }
43.  
44. private TableColumn currentColumn = null;
45.  
46. /* (non-Javadoc)
47. * @see org.eclipse.jface.viewers.ViewerSorter#getCollator()
48. */
49. public int compare (Viewer viewer, Object obj1, Object obj2 ) {
50. int rc = - 1;
51. // get the data
52. AbstractBaseElement data1 = (AbstractBaseElement ) obj1;
53. AbstractBaseElement data2 = (AbstractBaseElement ) obj2;
54.  
55. CollationKey key1 = null;
56. CollationKey key2 = null;
57.  
58. if ( this. currentColumn == ( (TableViewer )viewer ). getTable ( ). getColumn ( 0 ) ) {
59. key1 = getCollator ( ). getCollationKey (data1. getId ( ) );
60. key2 = getCollator ( ). getCollationKey (data2. getId ( ) );
61.  
62. }
63. else if ( this. currentColumn == ( (TableViewer )viewer ). getTable ( ). getColumn ( 1 ) ) {
64. key1 = getCollator ( ). getCollationKey (data1. getName ( ) );
65. key2 = getCollator ( ). getCollationKey (data2. getName ( ) );
66. }
67. else if ( this. currentColumn == ( (TableViewer )viewer ). getTable ( ). getColumn ( 2 ) ) {
68. key1 = getCollator ( ). getCollationKey (data1. getDescription ( ) );
69. key2 = getCollator ( ). getCollationKey (data2. getDescription ( ) );
70. }
71. // replace null-strings with empty-strings
72. if (key1 == null )
73. key1 = getCollator ( ). getCollationKey ( "" ); //$NON-NLS-1$
74.  
75. if (key2 == null )
76. key2 = getCollator ( ). getCollationKey ( "" ); //$NON-NLS-1$
77.  
78. if (isDescending ( this. currentColumn ) ) {
79. rc = key1. compareTo (key2 );
80. }
81. else {
82. rc = key2. compareTo (key1 );
83. }
84. return rc;
85. }
86.  
87. /**
88. * Sets the sort column.
89. * @param currentColumn The currentColumn to set.
90. */
91. public void setCurrentColumn ( TableColumn currentColumn ) {
92. this. currentColumn  = currentColumn;
93. pushSortCriteria (currentColumn );
94. }
95. }
96.  

This sorter you can use everywhere, you just have to modify the Creation of the Collator-Keys.

Direction Indicator
This feature will be aviable in Eclipse 3.2

Download the JFace TableSorter Plugin (Requires Model-Plugin)
Download the JFace TableSorter RCP (source included)