StripedJXTreeTable.java

package org.limewire.ui.swing.table;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;

import javax.swing.table.TableColumn;
import javax.swing.table.TableColumnModel;

import org.jdesktop.swingx.JXTreeTable;
import org.jdesktop.swingx.decorator.ColorHighlighter;
import org.jdesktop.swingx.decorator.CompoundHighlighter;
import org.jdesktop.swingx.treetable.TreeTableModel;

public class StripedJXTreeTable extends JXTreeTable {

    public StripedJXTreeTable() {
        super();
    }

    public StripedJXTreeTable(TreeTableModel treeModel) {
        super(treeModel);
    }

    /**
     * The parent paints all the real rows then the remaining space is
     * calculated and appropriately painted with grid lines and background
     * colors. These rows are not selectable.
     */
    @Override
    public void paint(Graphics g) {
        super.paint(g);
        paintEmptyRows(g);
    }

    /**
     * Paints fake rows to fill the viewport.
     */
    protected void paintEmptyRows(Graphics g) {
        final int rowCount = getRowCount();
        final Rectangle clip = g.getClipBounds();
        final int height = clip.y + clip.height;

        // paint rows and horizontal lines
        if (rowCount * rowHeight < height) {
            for (int i = rowCount; i <= height / rowHeight; ++i) {
                g.setColor(getColorForRow(i));
                g.fillRect(clip.x, i * rowHeight, clip.width, rowHeight);

                // paint horizontal rows if they're shown
                if (getShowHorizontalLines() && i > rowCount) {
                    g.setColor(gridColor);
                    g.drawLine(clip.x, i * rowHeight, clip.width, i * rowHeight);
                }
            }

            // paint vertical lines if they're shown
            if (getShowVerticalLines()) {
                g.setColor(gridColor);
                TableColumnModel columnModel = getColumnModel();
                int x = 0;
                for (int i = 0; i < columnModel.getColumnCount(); ++i) {
                    TableColumn column = columnModel.getColumn(i);
                    x += column.getWidth();
                    g.drawLine(x - 1, rowCount * rowHeight, x - 1, height);
                }
            }

        }
    }

    /**
     * Gets the background color for the row. This is assuming 1) there's no row
     * highlighter or 2) there's only an alternate row highlighter. Anything
     * else and the behaviour is unknown
     * 
     * @param row row to paint
     * @return Color to paint with
     */
    protected Color getColorForRow(int row) {
        return (row % 2 == 0) ? getHighlighterColor(0) : getHighlighterColor(1);
    }

    private Color getHighlighterColor(int index) {
        if (getHighlighters() == null || getHighlighters().length == 0)
            return getBackground();
        else if (getHighlighters()[0] instanceof CompoundHighlighter) {
            if (((CompoundHighlighter) getHighlighters()[0]).getHighlighters().length <= index)
                return getBackground();
            else
                return ((ColorHighlighter) ((CompoundHighlighter) getHighlighters()[0])
                        .getHighlighters()[index]).getBackground();
        } else if (getHighlighters()[0] instanceof ColorHighlighter) {
            if (getHighlighters().length <= index)
                return getBackground();
            else
                return ((ColorHighlighter) getHighlighters()[index]).getBackground();

        }
        return getBackground();
    }
}