JTreeのノードタイトルを複数行表示する

class MultiLineCellRenderer extends JPanel implements TreeCellRenderer {
  private DefaultTreeCellRenderer renderer = new DefaultTreeCellRenderer();
  private final JLabel icon = new JLabel();
  private final JTextArea text = new CellTextArea2();

  public MultiLineCellRenderer() {
    super(new BorderLayout(0, 0));
    text.setOpaque(true);
    text.setFont(icon.getFont());
    text.setBorder(BorderFactory.createEmptyBorder());
    icon.setOpaque(true);
    icon.setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 2));
    icon.setVerticalAlignment(SwingConstants.TOP);
    setOpaque(false);
    setBorder(BorderFactory.createEmptyBorder(1, 1, 1, 1));
    add(icon, BorderLayout.WEST);
    add(text);
  }

  @Override public Component getTreeCellRendererComponent(
      JTree tree, Object value, boolean isSelected, boolean expanded,
      boolean leaf, int row, boolean hasFocus) {
    JLabel l = (JLabel) renderer.getTreeCellRendererComponent(
      tree, value, isSelected, expanded, leaf, row, hasFocus);
    Color bColor, fColor;
    if (isSelected) {
      bColor = renderer.getBackgroundSelectionColor();
      fColor = renderer.getTextSelectionColor();
    } else {
      bColor = renderer.getBackgroundNonSelectionColor();
      fColor = renderer.getTextNonSelectionColor();
      if (bColor == null) bColor = renderer.getBackground();
      if (fColor == null) fColor = renderer.getForeground();
    }
    text.setFont(l.getFont());
    text.setText(l.getText());
    text.setForeground(fColor);
    text.setBackground(bColor);
    icon.setIcon(l.getIcon());
    icon.setBackground(bColor);
    return this;
  }

  @Override public void updateUI() {
    super.updateUI();
    renderer = new DefaultTreeCellRenderer();
  }
}

class CellTextArea2 extends JTextArea {
  @Override public Dimension getPreferredSize() {
    Dimension d = new Dimension(10, 10);
    Insets i = getInsets();
    d.width  = Math.max(
      d.width,  getColumns() * getColumnWidth() + i.left + i.right);
    d.height = Math.max(
      d.height, getRows() * getRowHeight() + i.top + i.bottom);
    return d;
  }

  @Override public void setText(String str) {
    super.setText(str);
    FontMetrics fm = getFontMetrics(getFont());
    Document doc   = getDocument();
    Element root   = doc.getDefaultRootElement();
    int lineCount  = root.getElementCount();
    int maxWidth   = 10;
    try {
      for (int i = 0; i < lineCount; i++) {
        Element e = root.getElement(i);
        int rangeStart = e.getStartOffset();
        int rangeEnd = e.getEndOffset();
        String line = doc.getText(rangeStart, rangeEnd - rangeStart);
        int width = fm.stringWidth(line);
        if (maxWidth < width) {
          maxWidth = width;
        }
      }
    } catch (Exception ex) {
      ex.printStackTrace();
    }
    setRows(lineCount);
    setColumns(1 + maxWidth / getColumnWidth());
  }
}