An implementation of RowSorter that provides sorting
and filtering using a TableModel.
The following example shows adding sorting to a JTable:
TableModel myModel = createMyTableModel();
JTable table = new JTable(myModel);
table.setRowSorter(new TableRowSorter(myModel));
This will do all the wiring such that when the user does the appropriate
gesture, such as clicking on the column header, the table will
visually sort.
JTable's row-based methods and JTable's
selection model refer to the view and not the underlying
model. Therefore, it is necessary to convert between the two. For
example, to get the selection in terms of myModel
you need to convert the indices:
int[] selection = table.getSelectedRows();
for (int i = 0; i < selection.length; i++) {
selection[i] = table.convertRowIndexToModel(selection[i]);
}
Similarly to select a row in JTable based on
a coordinate from the underlying model do the inverse:
table.setRowSelectionInterval(table.convertRowIndexToView(row),
table.convertRowIndexToView(row));
The previous example assumes you have not enabled filtering. If you
have enabled filtering convertRowIndexToView will return
-1 for locations that are not visible in the view.
TableRowSorter uses Comparators for doing
comparisons. The following defines how a Comparator is
chosen for a column:
- If a
Comparator has been specified for the column by the
setComparator method, use it.
- If the column class as returned by
getColumnClass is
String, use the Comparator returned by
Collator.getInstance().
- If the column class implements
Comparable, use a
Comparator that invokes the compareTo
method.
- If a
TableStringConverter has been specified, use it
to convert the values to Strings and then use the
Comparator returned by Collator.getInstance().
- Otherwise use the
Comparator returned by
Collator.getInstance() on the results from
calling toString on the objects.
In addition to sorting TableRowSorter provides the ability
to filter. A filter is specified using the setFilter
method. The following example will only show rows containing the string
"foo":
TableModel myModel = createMyTableModel();
TableRowSorter sorter = new TableRowSorter(myModel);
sorter.setRowFilter(RowFilter.regexFilter(".*foo.*"));
JTable table = new JTable(myModel);
table.setRowSorter(sorter);
If the underlying model structure changes (the
modelStructureChanged method is invoked) the following
are reset to their default values: Comparators by
column, current sort order, and whether each column is sortable. The default
sort order is natural (the same as the model), and columns are
sortable by default.
TableRowSorter has one formal type parameter: the type
of the model. Passing in a type that corresponds exactly to your
model allows you to filter based on your model without casting.
Refer to the documentation of RowFilter for an example
of this.
WARNING: DefaultTableModel returns a column
class of Object. As such all comparisons will
be done using toString. This may be unnecessarily
expensive. If the column only contains one type of value, such as
an Integer, you should override getColumnClass and
return the appropriate Class. This will dramatically
increase the performance of this class. | 