Custom Cell Renderers and Custom Cell Editors in Swing - Part I

JTable provides the ability for individual columns to have different renderers and editors. This is very powerful functionality because you can have a Radio Button in one of the columns or a JButton or JComboBox in some columns.

I went ahead a wrote a small JTable Component that displays a Radio Button in one of its columns. I also customized the component to display the radio button only for specific rows in the column and also added functionality to behave as a radio button group!

The JTable that I wrote has the ability for some external controller to specify
which rows of a particular column must render its value as RadioButtons.
I achieved this by writing an interface with a single method which provided
any renderer with the ability to check if the current row, column can be
rendered by itself.

/**    * CellRendererValidator - This is an interface     * that will be implemented by any class that     * wishes <br>to specify whether a CellRenderer     * is valid for a specific column and row. <br>    * This is pretty useful when specific rows of a     * column will <i>NOT </i> the renderer set for     * the entire column    *     * @author rajeshv    */   public static interface CellRendererValidator {     public boolean isValid(JTable table,                            int rowIndex,int colIndex);   }

I also wrote a TableCellRenderer and TableCellEditor for the RadioButton Column. Here the code for Both.

RadioColumnRenderer:

import java.awt.Color; import java.awt.Component; import javax.swing.JRadioButton; import javax.swing.JTable; import javax.swing.SwingConstants; import javax.swing.table.TableCellRenderer; public class RadioColumnRenderer extends JRadioButton     implements TableCellRenderer {   private CustomJTable.CellRendererValidator                                      validator = null;   /**    *     */   public RadioColumnRenderer(       CustomJTable.CellRendererValidator validator) {     this.validator = validator;   }   public Component getTableCellRendererComponent(       JTable table, Object value, boolean isSelected,       boolean hasFocus, int row, int column) {     // this is necessary because we may have      // values that are not boolean for     // som of the columns     this.setSelected(value != null         && value.getClass().getName().equals(             Boolean.class.getName())         && ((Boolean) value).booleanValue());     this.setHorizontalAlignment(                           SwingConstants.CENTER);     this.setOpaque(false);     this.setBackground(Color.WHITE);     // request the validator to concur that this      // column can be rendered as a JRadioButton     if (validator != null) {       if (validator.isValid(table, row, column)) {         return this;       }       return null;     }     return this;   } }