TableSorter is a decorator for TableModels : Table Model « Swing JFC « Java

TableSorter is a decorator for TableModels


import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.Icon;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.AbstractTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableColumnModel;
import javax.swing.table.TableModel;

 * TableSorter is a decorator for TableModels; adding sorting
 * functionality to a supplied TableModel. TableSorter does
 * not store or copy the data in its TableModel; instead it maintains
 * a map from the row indexes of the view to the row indexes of the
 * model. As requests are made of the sorter (like getValueAt(row, col))
 * they are passed to the underlying model after the row numbers
 * have been translated via the internal mapping array. This way,
 * the TableSorter appears to hold another copy of the table
 * with the rows in a different order.
 * <p/>
 * TableSorter registers itself as a listener to the underlying model,
 * just as the JTable itself would. Events recieved from the model
 * are examined, sometimes manipulated (typically widened), and then
 * passed on to the TableSorter's listeners (typically the JTable).
 * If a change to the model has invalidated the order of TableSorter's
 * rows, a note of this is made and the sorter will resort the
 * rows the next time a value is requested.
 * <p/>
 * When the tableHeader property is set, either by using the
 * setTableHeader() method or the two argument constructor, the
 * table header may be used as a complete UI for TableSorter.
 * The default renderer of the tableHeader is decorated with a renderer
 * that indicates the sorting status of each column. In addition,
 * a mouse listener is installed with the following behavior:
 * <ul>
 * <li>
 * Mouse-click: Clears the sorting status of all other columns
 * and advances the sorting status of that column through three
 * values: {NOT_SORTED, ASCENDING, DESCENDING} (then back to
 * NOT_SORTED again).
 * <li>
 * SHIFT-mouse-click: Clears the sorting status of all other columns
 * and cycles the sorting status of the column through the same
 * three values, in the opposite order: {NOT_SORTED, DESCENDING, ASCENDING}.
 * <li>
 * CONTROL-mouse-click and CONTROL-SHIFT-mouse-click: as above except
 * that the changes to the column do not cancel the statuses of columns
 * that are already sorting - giving a way to initiate a compound
 * sort.
 * </ul>
 * <p/>
 * This is a long overdue rewrite of a class of the same name that
 * first appeared in the swing table demos in 1997.
 * @author Philip Milne
 * @author Brendon McLean
 * @author Dan van Enckevort
 * @author Parwinder Sekhon
 * @version 2.0 02/27/04
public class TableSorter extends AbstractTableModel {

    protected TableModel           tableModel;
    public static final int        DESCENDING            = -1;
    public static final int        NOT_SORTED            = 0;
    public static final int        ASCENDING             = 1;
    private static Directive EMPTY_DIRECTIVE = new Directive(-1, NOT_SORTED);
    public static final Comparator COMPARABLE_COMPARATOR = new Comparator() {

        public int compare(Object o1, Object o2) {

            if (o1 == o2) {
                return 0;

            if (o1 == null) {
                if (o2 == null) {
                    return 0;

                return -1;

            if (o2 == null) {
                return 1;

            return ((Comparable) o1).compareTo(o2);
    public static final Comparator LEXICAL_COMPARATOR = new Comparator() {

        public int compare(Object o1, Object o2) {
            return o1.toString().compareTo(o2.toString());
    private Row[]              viewToModel;
    private int[]              modelToView;
    private JTableHeader       tableHeader;
    private MouseListener      mouseListener;
    private TableModelListener tableModelListener;
    private Map                columnComparators = new HashMap();
    private List               sortingColumns    = new ArrayList();

    public TableSorter() {
        this.mouseListener      = new MouseHandler();
        this.tableModelListener = new TableModelHandler();

    public TableSorter(TableModel tableModel) {



    public TableSorter(TableModel tableModel, JTableHeader tableHeader) {



    private void clearSortingState() {
        viewToModel = null;
        modelToView = null;

    public TableModel getTableModel() {
        return tableModel;

    public void setTableModel(TableModel tableModel) {

        if (this.tableModel != null) {

        this.tableModel = tableModel;

        if (this.tableModel != null) {


    public JTableHeader getTableHeader() {
        return tableHeader;

    public void setTableHeader(JTableHeader tableHeader) {

        if (this.tableHeader != null) {

            TableCellRenderer defaultRenderer =

            if (defaultRenderer instanceof SortableHeaderRenderer) {
                    ((SortableHeaderRenderer) defaultRenderer)

        this.tableHeader = tableHeader;

        if (this.tableHeader != null) {
                new SortableHeaderRenderer(

    public boolean isSorting() {
        return sortingColumns.size() != 0;

    private Directive getDirective(int column) {

        for (int i = 0; i < sortingColumns.size(); i++) {
            Directive directive = (Directive) sortingColumns.get(i);

            if (directive.column == column) {
                return directive;

        return EMPTY_DIRECTIVE;

    public int getSortingStatus(int column) {
        return getDirective(column).direction;

    private void sortingStatusChanged() {


        if (tableHeader != null) {

    public void setSortingStatus(int column, int status) {

        Directive directive = getDirective(column);

        if (directive != EMPTY_DIRECTIVE) {

        if (status != NOT_SORTED) {
            sortingColumns.add(new Directive(column, status));


    protected Icon getHeaderRendererIcon(int column, int size) {

        Directive directive = getDirective(column);

        if (directive == EMPTY_DIRECTIVE) {
            return null;

        return new Arrow(directive.direction == DESCENDING, size,

    private void cancelSorting() {

    public void setColumnComparator(Class type, Comparator comparator) {

        if (comparator == null) {
        } else {
            columnComparators.put(type, comparator);

    protected Comparator getComparator(int column) {

        Class columnType = tableModel.getColumnClass(column);
        Comparator comparator =
            (Comparator) columnComparators.get(columnType);

        if (comparator != null) {
            return comparator;

        if (Comparable.class.isAssignableFrom(columnType)) {
            return COMPARABLE_COMPARATOR;

        return LEXICAL_COMPARATOR;

    private Row[] getViewToModel() {

        if (viewToModel == null) {
            int tableModelRowCount = tableModel.getRowCount();

            viewToModel = new Row[tableModelRowCount];

            for (int row = 0; row < tableModelRowCount; row++) {
                viewToModel[row] = new Row(row);

            if (isSorting()) {

        return viewToModel;

    public int modelIndex(int viewIndex) {
        return getViewToModel()[viewIndex].modelIndex;

    private int[] getModelToView() {

        if (modelToView == null) {
            int n = getViewToModel().length;

            modelToView = new int[n];

            for (int i = 0; i < n; i++) {
                modelToView[modelIndex(i)] = i;

        return modelToView;

    // TableModel interface methods
    public int getRowCount() {
        return (tableModel == null) ? 0
                                    : tableModel.getRowCount();

    public int getColumnCount() {
        return (tableModel == null) ? 0
                                    : tableModel.getColumnCount();

    public String getColumnName(int column) {
        return tableModel.getColumnName(column);

    public Class getColumnClass(int column) {
        return tableModel.getColumnClass(column);

    public boolean isCellEditable(int row, int column) {
        return tableModel.isCellEditable(modelIndex(row), column);

    public Object getValueAt(int row, int column) {
        return tableModel.getValueAt(modelIndex(row), column);

    public void setValueAt(Object aValue, int row, int column) {
        tableModel.setValueAt(aValue, modelIndex(row), column);

    // Helper classes
    private class Row implements Comparable {

        private int modelIndex;

        public Row(int index) {
            this.modelIndex = index;

        public int compareTo(Object o) {

            int row1 = modelIndex;
            int row2 = ((Row) o).modelIndex;

            for (Iterator it = sortingColumns.iterator(); it.hasNext(); ) {
                Directive directive  = (Directive);
                int       column     = directive.column;
                Object    o1         = tableModel.getValueAt(row1, column);
                Object    o2         = tableModel.getValueAt(row2, column);
                int       comparison = 0;

                // Define null less than everything, except null.
                if (o1 == null && o2 == null) {
                    comparison = 0;
                } else if (o1 == null) {
                    comparison = -1;
                } else if (o2 == null) {
                    comparison = 1;
                } else {
                    comparison = getComparator(column).compare(o1, o2);

                if (comparison != 0) {
                    return directive.direction == DESCENDING ? -comparison
                                                             : comparison;

            return 0;

    private class TableModelHandler implements TableModelListener {

        public void tableChanged(TableModelEvent e) {

            // If we're not sorting by anything, just pass the event along.
            if (!isSorting()) {


            // If the table structure has changed, cancel the sorting; the
            // sorting columns may have been either moved or deleted from
            // the model.
            if (e == null || e.getFirstRow() == TableModelEvent.HEADER_ROW) {


            // We can map a cell event through to the view without widening
            // when the following conditions apply:
            // a) all the changes are on one row (e.getFirstRow() == e.getLastRow()) and,
            // b) all the changes are in one column (column != TableModelEvent.ALL_COLUMNS) and,
            // c) we are not sorting on that column (getSortingStatus(column) == NOT_SORTED) and,
            // d) a reverse lookup will not trigger a sort (modelToView != null)
            // Note: INSERT and DELETE events fail this test as they have column == ALL_COLUMNS.
            // The last check, for (modelToView != null) is to see if modelToView
            // is already allocated. If we don't do this check; sorting can become
            // a performance bottleneck for applications where cells
            // change rapidly in different parts of the table. If cells
            // change alternately in the sorting column and then outside of
            // it this class can end up re-sorting on alternate cell updates -
            // which can be a performance problem for large tables. The last
            // clause avoids this problem.
            int column = e.getColumn();

            if (e.getFirstRow() == e.getLastRow()
                    && column != TableModelEvent.ALL_COLUMNS
                    && getSortingStatus(column) == NOT_SORTED
                    && modelToView != null) {
                int viewIndex = getModelToView()[e.getFirstRow()];

                fireTableChanged(new TableModelEvent(TableSorter.this,
                                                     viewIndex, viewIndex,
                                                     column, e.getType()));


            // Something has happened to the data that may have invalidated the row order.


    private class MouseHandler extends MouseAdapter {

        public void mouseClicked(MouseEvent e) {

            JTableHeader     h           = (JTableHeader) e.getSource();
            TableColumnModel columnModel = h.getColumnModel();
            int viewColumn = columnModel.getColumnIndexAtX(e.getX());
            int column = columnModel.getColumn(viewColumn).getModelIndex();

            if (column != -1) {
                int status = getSortingStatus(column);

                if (!e.isControlDown()) {

                // Cycle the sorting states through {NOT_SORTED, ASCENDING, DESCENDING} or
                // {NOT_SORTED, DESCENDING, ASCENDING} depending on whether shift is pressed.
                status = status + (e.isShiftDown() ? -1
                                                   : 1);
                status = (status + 4) % 3 - 1;    // signed mod, returning {-1, 0, 1}

                setSortingStatus(column, status);

    private static class Arrow implements Icon {

        private boolean descending;
        private int     size;
        private int     priority;

        public Arrow(boolean descending, int size, int priority) {

            this.descending = descending;
            this.size       = size;
            this.priority   = priority;

        public void paintIcon(Component c, Graphics g, int x, int y) {

            Color color = c == null ? Color.gray
                                    : c.getBackground();

            // In a compound sort, make each succesive triangle 20%
            // smaller than the previous one.
            int dx = (int) (size / 2 * Math.pow(0.8, priority));
            int dy = descending ? dx
                                : -dx;

            // Align icon (roughly) with font baseline.
            y = y + 5 * size / 6 + (descending ? -dy
                                               : 0);

            int shift = descending ? 1
                                   : -1;

            g.translate(x, y);

            // Right diagonal.
            g.drawLine(dx / 2, dy, 0, 0);
            g.drawLine(dx / 2, dy + shift, 0, shift);

            // Left diagonal.
            g.drawLine(dx / 2, dy, dx, 0);
            g.drawLine(dx / 2, dy + shift, dx, shift);

            // Horizontal line.
            if (descending) {
            } else {

            g.drawLine(dx, 0, 0, 0);
            g.translate(-x, -y);

        public int getIconWidth() {
            return size;

        public int getIconHeight() {
            return size;

    private class SortableHeaderRenderer implements TableCellRenderer {

        private TableCellRenderer tableCellRenderer;

        public SortableHeaderRenderer(TableCellRenderer tableCellRenderer) {
            this.tableCellRenderer = tableCellRenderer;

        public Component getTableCellRendererComponent(JTable table,
                Object value, boolean isSelected, boolean hasFocus, int row,
                int column) {

            Component c =
                tableCellRenderer.getTableCellRendererComponent(table, value,
                    isSelected, hasFocus, row, column);

            if (c instanceof JLabel) {
                JLabel l = (JLabel) c;


                int modelColumn = table.convertColumnIndexToModel(column);


            return c;

    private static class Directive {

        private int column;
        private int direction;

        public Directive(int column, int direction) {
            this.column    = column;
            this.direction = direction;


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