this.subrange = NORMAL;
            }
            else if (inSubrange(WARNING, value)) {
               this.subrange = WARNING;
            }
            else if (inSubrange(CRITICAL, value)) {
                this.subrange = CRITICAL;
            }
            else {
                this.subrange = -1;
            }
            setAxisRange();
        }
        super.datasetChanged(event);
    }

    /**
     * Returns the minimum value in either the domain or the range, whichever
     * is displayed against the vertical axis for the particular type of plot
     * implementing this interface.
     *
     * @return The minimum value in either the domain or the range.
     */
    public Number getMinimumVerticalDataValue() {
        return new Double(this.lowerBound);
    }

    /**
     * Returns the maximum value in either the domain or the range, whichever
     * is displayed against the vertical axis for the particular type of plot
     * implementing this interface.
     *
     * @return The maximum value in either the domain or the range
     */
    public Number getMaximumVerticalDataValue() {
        return new Double(this.upperBound);
    }

    /**
     * Returns the data range.
     *
     * @param axis  the axis.
     *
     * @return The range of data displayed.
     */
    public Range getDataRange(ValueAxis axis) {
       return new Range(this.lowerBound, this.upperBound);
    }

    /**
     * Sets the axis range to the current values in the rangeInfo array.
     */
    protected void setAxisRange() {
        if ((this.subrange >= 0) && (this.followDataInSubranges)) {
            this.rangeAxis.setRange(
                new Range(this.subrangeInfo[this.subrange][DISPLAY_LOW],
                this.subrangeInfo[this.subrange][DISPLAY_HIGH])
            );
        }
        else {
            this.rangeAxis.setRange(this.lowerBound, this.upperBound);
        }
    }

    /**
     * Returns the legend items for the plot.
     *
     * @return <code>null</code>.
     */
    public LegendItemCollection getLegendItems() {
        return null;
    }

    /**
     * Returns the orientation of the plot.
     * 
     * @return The orientation (always {@link PlotOrientation#VERTICAL}).
     */
    public PlotOrientation getOrientation() {
        return PlotOrientation.VERTICAL;    
    }

    /**
     * Determine whether a number is valid and finite.
     *
     * @param d  the number to be tested.
     *
     * @return <code>true</code> if the number is valid and finite, and 
     *         <code>false</code> otherwise.
     */
    protected static boolean isValidNumber(double d) {
        return (!(Double.isNaN(d) || Double.isInfinite(d)));
    }

    /**
     * Returns true if the value is in the specified range, and false otherwise.
     *
     * @param subrange  the subrange.
     * @param value  the value to check.
     *
     * @return A boolean.
     */
    private boolean inSubrange(int subrange, double value) {
        return (value > this.subrangeInfo[subrange][RANGE_LOW]
            && value <= this.subrangeInfo[subrange][RANGE_HIGH]);
    }

    /**
     * Returns the mercury paint corresponding to the current data value.
     *
     * @return The paint.
     */
    private Paint getCurrentPaint() {

        Paint result = this.mercuryPaint;
        if (this.useSubrangePaint) {
            double value = this.dataset.getValue().doubleValue();
            if (inSubrange(NORMAL, value)) {
                result = this.subrangePaint[NORMAL];
            }
            else if (inSubrange(WARNING, value)) {
                result = this.subrangePaint[WARNING];
            }
            else if (inSubrange(CRITICAL, value)) {
                result = this.subrangePaint[CRITICAL];
            }
        }
        return result;
    }

    /**
     * Tests this plot for equality with another object.  The plot's dataset
     * is not considered in the test.
     *
     * @param obj  the object (<code>null</code> permitted).
     *
     * @return <code>true</code> or <code>false</code>.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof ThermometerPlot)) {
            return false;
        }
        ThermometerPlot that = (ThermometerPlot) obj;
        if (!super.equals(obj)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.rangeAxis, that.rangeAxis)) {
            return false;
        }
        if (this.axisLocation != that.axisLocation) {
            return false;   
        }
        if (this.lowerBound != that.lowerBound) {
            return false;
        }
        if (this.upperBound != that.upperBound) {
            return false;
        }
        if (!ObjectUtilities.equal(this.padding, that.padding)) {
            return false;
        }
        if (!ObjectUtilities.equal(
            this.thermometerStroke, that.thermometerStroke
        )) {
            return false;
        }
        if (!PaintUtilities.equal(
            this.thermometerPaint, that.thermometerPaint
        )) {
            return false;
        }
        if (this.units != that.units) {
            return false;
        }
        if (this.valueLocation != that.valueLocation) {
            return false;
        }
        if (!ObjectUtilities.equal(this.valueFont, that.valueFont)) {
            return false;
        }
        if (!PaintUtilities.equal(this.valuePaint, that.valuePaint)) {
            return false;
        }
        if (!ObjectUtilities.equal(this.valueFormat, that.valueFormat)) {
            return false;
        }
        if (!PaintUtilities.equal(this.mercuryPaint, that.mercuryPaint)) {
            return false;
        }
        if (this.showValueLines != that.showValueLines) {
            return false;
        }
        if (this.subrange != that.subrange) {
            return false;
        }
        if (this.followDataInSubranges != that.followDataInSubranges) {
            return false;
        }
        if (!equal(this.subrangeInfo, that.subrangeInfo)) {
            return false;   
        }
        if (this.useSubrangePaint != that.useSubrangePaint) {
            return false;
        }
        for (int i = 0; i < this.subrangePaint.length; i++) {
            if (!PaintUtilities.equal(this.subrangePaint[i], 
                    that.subrangePaint[i])) {
                return false;   
            }
        }
        return true;
    }

    /**
     * Tests two double[][] arrays for equality.
     * 
     * @param array1  the first array (<code>null</code> permitted).
     * @param array2  the second arrray (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    private static boolean equal(double[][] array1, double[][] array2) {
        if (array1 == null) {
            return (array2 == null);
        }
        if (array2 == null) {
            return false;
        }
        if (array1.length != array2.length) {
            return false;
        }
        for (int i = 0; i < array1.length; i++) {
            if (!Arrays.equals(array1[i], array2[i])) {
                return false;
            }
        }
        return true;
    }

    /**
     * Returns a clone of the plot.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException  if the plot cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {

        ThermometerPlot clone = (ThermometerPlot) super.clone();

        if (clone.dataset != null) {
            clone.dataset.addChangeListener(clone);
        }
        clone.rangeAxis = (ValueAxis) ObjectUtilities.clone(this.rangeAxis);
        if (clone.rangeAxis != null) {
            clone.rangeAxis.setPlot(clone);
            clone.rangeAxis.addChangeListener(clone);
        }
        clone.valueFormat = (NumberFormat) this.valueFormat.clone();
        clone.subrangePaint = (Paint[]) this.subrangePaint.clone();

        return clone;

    }

    /**
     * Provides serialization support.
     *
     * @param stream  the output stream.
     *
     * @throws IOException  if there is an I/O error.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException { 
        stream.defaultWriteObject();
        SerialUtilities.writeStroke(this.thermometerStroke, stream);
        SerialUtilities.writePaint(this.thermometerPaint, stream);
        SerialUtilities.writePaint(this.valuePaint, stream);
        SerialUtilities.writePaint(this.mercuryPaint, stream);
        SerialUtilities.writeStroke(this.subrangeIndicatorStroke, stream);
        SerialUtilities.writeStroke(this.rangeIndicatorStroke, stream);
    }

    /**
     * Provides serialization support.
     *
     * @param stream  the input stream.
     *
     * @throws IOException  if there is an I/O error.
     * @throws ClassNotFoundException  if there is a classpath problem.
     */
    private void readObject(ObjectInputStream stream) throws IOException,
            ClassNotFoundException {
        stream.defaultReadObject();
        this.thermometerStroke = SerialUtilities.readStroke(stream);
        this.thermometerPaint = SerialUtilities.readPaint(stream);
        this.valuePaint = SerialUtilities.readPaint(stream);
        this.mercuryPaint = SerialUtilities.readPaint(stream);
        this.subrangeIndicatorStroke = SerialUtilities.readStroke(stream);
        this.rangeIndicatorStroke = SerialUtilities.readStroke(stream);

        if (this.rangeAxis != null) {
            this.rangeAxis.addChangeListener(this);
        }
    }

    /**
     * Multiplies the range on the domain axis/axes by the specified factor.
     *
     * @param factor  the zoom factor.
     * @param state  the plot state.
     * @param source  the source point.
     */
    public void zoomDomainAxes(double factor, PlotRenderingInfo state, 
                               Point2D source) {
        // TODO: to be implemented.
    }

    /**
     * Multiplies the range on the range axis/axes by the specified factor.
     *
     * @param factor  the zoom factor.
     * @param state  the plot state.
     * @param source  the source point.
     */
    public void zoomRangeAxes(double factor, PlotRenderingInfo state, 
                              Point2D source) {
        this.rangeAxis.resizeRange(factor);
    }

    /**
     * This method does nothing.
     *
     * @param lowerPercent  the lower percent.
     * @param upperPercent  the upper percent.
     * @param state  the plot state.
     * @param source  the source point.
     */
    public void zoomDomainAxes(double lowerPercent, double upperPercent, 
                               PlotRenderingInfo state, Point2D source) {
        // no domain axis to zoom
    }

    /**
     * Zooms the range axes.
     *
     * @param lowerPercent  the lower percent.
     * @param upperPercent  the upper percent.
     * @param state  the plot state.
     * @param source  the source point.
     */
    public void zoomRangeAxes(double lowerPercent, double upperPercent, 
                              PlotRenderingInfo state, Point2D source) {
        this.rangeAxis.zoomRange(lowerPercent, upperPercent);
    }
  
    /**
     * Returns <code>false</code>.
     * 
     * @return A boolean.
     */
    public boolean isDomainZoomable() {
        return false;
    }
    
    /**
     * Returns <code>true</code>.
     * 
     * @return A boolean.
     */
    public boolean isRangeZoomable() {
        return true;
    }

}