ButtonHandler

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.table.*;
 
/**
 * The ButtonHandler class handles JTable buttons. Usage example:
 * <p>
 * <pre>
 * class MyTable extends JTable {
 * 
 *     private ButtonHandler btHandler;
 * 
 *     MyTable() {
 *         super(10, 4);
 *         String[] butonNames = {"Button1", "Button2", "Button3"};
 *         Object[] buttonPositions = new Object[]{new int[]{0, 0}, new int[]{0, 1}, new int[]{0, 2}};
 *         for (int i = 0; i < buttonPositions.length; i++) {
 *             int[] pos = (int[]) buttonPositions[i];
 *             setValueAt(butonNames[i], pos[0], pos[1]);
 *         }
 *         Action action = new AbstractAction() {
 *             public void actionPerformed(final ActionEvent e) {
 *                 String[] buttonPosition = e.getActionCommand().split(",");
 *                 int row = Integer.parseInt(buttonPosition[0]);
 *                 int column = Integer.parseInt(buttonPosition[1]);
 *                 System.out.println("row = " + row + ", column = " + column);
 *             }
 *         };
 *         btHandler = new ButtonHandler(this, action, buttonPositions);
 *     }
 *     public TableCellRenderer getCellRenderer(final int row, final int column) {
 *         return btHandler.getRenderer(row, column);
 *     }
 *     public TableCellEditor getCellEditor(final int row, final int column) {
 *         return btHandler.getEditor(row, column);
 *     }
 * }
 * </pre>
 * <p>
 * @author André Uhres
 */
class ButtonHandler {
 
    private JTable table;
    private Action action;
    private Border originalBorder;
    private Border focusBorder;
    private final Editor buttonEditor;
    private final Renderer buttonRenderer;
    private final Object[] buttonPositions;
 
    /**
     * Creates a ButtonHandler for the JTable passed as parameter.
     * @param table
     * @param action the action to be performed by the buttons
     * @param buttonPositions an array of int[] row-column pairs representing the button positions
     */
    ButtonHandler(final JTable table, final Action action, final Object[] buttonPositions) {
        this.table = table;
        this.action = action;
        buttonRenderer = new Renderer();
        buttonEditor = new Editor();
        this.buttonPositions = buttonPositions;
    }
 
 
    /**
     * @param row
     * @param column
     * @return the TableCellEditor for the cell at row-column
     */
    public TableCellEditor getEditor(final int row, final int column) {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);
        TableCellEditor editor = tableColumn.getCellEditor();
        if (editor == null) {
            for (int i = 0; i < buttonPositions.length; i++) {
                int[] pos = (int[]) buttonPositions[i];
                if (pos[0] == row && pos[1] == column) {
                    return buttonEditor;
                }
            }
            Class c = table.getColumnClass(column);
            if (c.equals(Object.class)) {
                Object o = table.getValueAt(row, column);
                if (o != null) {
                    c = table.getValueAt(row, column).getClass();
                }
            }
            editor = table.getDefaultEditor(c);
        }
 
        return editor;
    }
 
    /**
     * @param row
     * @param column
     * @return the TableCellRenderer for the cell at row-column
     */
    public TableCellRenderer getRenderer(final int row, final int column) {
        TableColumn tableColumn = table.getColumnModel().getColumn(column);
        TableCellRenderer renderer = tableColumn.getCellRenderer();
        if (renderer == null) {
            for (int i = 0; i < buttonPositions.length; i++) {
                int[] pos = (int[]) buttonPositions[i];
                if (pos[0] == row && pos[1] == column) {
                    return buttonRenderer;
                }
            }
            Class c = table.getColumnClass(column);
            if (c.equals(Object.class)) {
                Object o = table.getValueAt(row, column);
                if (o != null) {
                    c = table.getValueAt(row, column).getClass();
                }
            }
            renderer = table.getDefaultRenderer(c);
        }
        return renderer;
    }
 
    private class Renderer implements TableCellRenderer {
 
        private JButton renderButton = new JButton();
 
        @Override
        public Component getTableCellRendererComponent(
                JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            if (isSelected) {
                renderButton.setForeground(table.getSelectionForeground());
                renderButton.setBackground(table.getSelectionBackground());
            } else {
                renderButton.setForeground(table.getForeground());
                renderButton.setBackground(UIManager.getColor("Button.background"));
            }
            if (hasFocus) {
                renderButton.setBorder(focusBorder);
            } else {
                renderButton.setBorder(originalBorder);
            }
            if (value == null) {
                renderButton.setText("");
                renderButton.setIcon(null);
            } else if (value instanceof Icon) {
                renderButton.setText("");
                renderButton.setIcon((Icon) value);
            } else {
                renderButton.setText(value.toString());
                renderButton.setIcon(null);
            }
            return renderButton;
        }
    }
 
    private class Editor extends AbstractCellEditor implements TableCellEditor {
 
        private JButton editButton;
        private Object editorValue;
 
        private Editor() {
            editButton = new JButton();
            editButton.setFocusPainted(false);
            editButton.addActionListener(new ActionListener() {
 
                @Override
                public void actionPerformed(final ActionEvent e) {
                    int row = table.convertRowIndexToModel(table.getEditingRow());
                    int column = table.convertColumnIndexToModel(table.getEditingColumn());
                    buttonEditor.stopCellEditing();
                    ActionEvent event = new ActionEvent(table,
                            ActionEvent.ACTION_PERFORMED,
                            row + "," + column);
                    action.actionPerformed(event);
                }
            });
            originalBorder = editButton.getBorder();
            focusBorder = new LineBorder(Color.BLUE);
            editButton.setBorder(focusBorder);
        }
 
        @Override
        public Component getTableCellEditorComponent(
                JTable table, Object value, boolean isSelected, int row, int column) {
            if (value == null) {
                editButton.setText("");
                editButton.setIcon(null);
            } else if (value instanceof Icon) {
                editButton.setText("");
                editButton.setIcon((Icon) value);
            } else {
                editButton.setText(value.toString());
                editButton.setIcon(null);
            }
            this.editorValue = value;
            return editButton;
        }
 
        @Override
        public Object getCellEditorValue() {
            return editorValue;
        }
    }
}