System.err.println("value extracted ok");
    public static double[] extractValues(Attribute[] attributes,                                         String elementName)        throws IllegalArgumentException    {        if(attributes == null || elementName == null)        {            throw new IllegalArgumentException("Null parameters at " +                "AbstractHeatMapMode.extractValues(Attribute[],String)");        }        double[] values = new double[attributes.length];        for(int i=0;i<attributes.length;i++)        {            values[i] = parseElement(attributes[i],elementName);        }        return values;    }