Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -3853824986520333437L;
    
    /** The default format string. */
    public static final String DEFAULT_TOOL_TIP_FORMAT_STRING 
        = "({0}, {1}) = {3} - {4}";
    
    /**
     * Creates a new generator with a default number formatter.
     */
    public IntervalCategoryToolTipGenerator() {
        super(DEFAULT_TOOL_TIP_FORMAT_STRING, NumberFormat.getInstance());
    }

    /**
     * Creates a new generator with the specified number formatter.
     *
     * @param labelFormat  the label format string (<code>null</code> not 
     *                     permitted).
     * @param formatter  the number formatter (<code>null</code> not permitted).
     */
    public IntervalCategoryToolTipGenerator(String labelFormat, 
                                            NumberFormat formatter) {
        super(labelFormat, formatter);
    }
    
    /**
     * Creates a new generator with the specified date formatter.
     *
     * @param labelFormat  the label format string (<code>null</code> not 
     *                     permitted).
     * @param formatter  the date formatter (<code>null</code> not permitted).
     */
    public IntervalCategoryToolTipGenerator(String labelFormat, 
                                            DateFormat formatter) {
        super(labelFormat, formatter);
    }
    
    /**
     * Creates the array of items that can be passed to the 
     * <code>MessageFormat</code> class for creating labels.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param row  the row index (zero-based).
     * @param column  the column index (zero-based).
     *
     * @return The items (never <code>null</code>).
     */
    protected Object[] createItemArray(CategoryDataset dataset, 
                                       int row, int column) {
        Object[] result = new Object[5];
        result[0] = dataset.getRowKey(row).toString();
        result[1] = dataset.getColumnKey(column).toString();
        Number value = dataset.getValue(row, column);
        if (getNumberFormat() != null) {
            result[2] = getNumberFormat().format(value);  
        }
        else if (getDateFormat() != null) {
            result[2] = getDateFormat().format(value);
        }
        
        if (dataset instanceof IntervalCategoryDataset) {
            IntervalCategoryDataset icd = (IntervalCategoryDataset) dataset;
            Number start = icd.getStartValue(row, column);
            Number end = icd.getEndValue(row, column);
            if (getNumberFormat() != null) {
                result[3] = getNumberFormat().format(start);  
                result[4] = getNumberFormat().format(end);  
            }
            else if (getDateFormat() != null) {
                result[3] = getDateFormat().format(start);
                result[4] = getDateFormat().format(end);
            }
        }
        return result;