question: public void drawRangeLine ( Graphics2D g2 , CategoryPlot plot , ValueAxis axis , Rectangle2D dataArea , double value , Paint paint , Stroke stroke ) { Range range = axis . getRange ( ) ; if ( ! range . contains ( value ) ) { return ; } PlotOrientation orientation = plot . getOrientation ( ) ; Line2D line = null ; double v = axis . valueToJava2D ( value , dataArea , plot . getRangeAxisEdge ( ) ) ; if ( orientation == PlotOrientation . HORIZONTAL ) { line = new Line2D . Double ( v , dataArea . getMinY ( ) , v , dataArea . getMaxY ( ) ) ; } else if ( orientation == PlotOrientation . VERTICAL ) { line = new Line2D . Double ( dataArea . getMinX ( ) , v , dataArea . getMaxX ( ) , v ) ; } g2 . setPaint ( paint ) ; g2 . setStroke ( stroke ) ; Object saved = g2 . getRenderingHint ( RenderingHints . KEY_STROKE_CONTROL ) ; g2 . setRenderingHint ( RenderingHints . KEY_STROKE_CONTROL , RenderingHints . VALUE_STROKE_NORMALIZE ) ; g2 . draw ( line ) ; g2 . setRenderingHint ( RenderingHints . KEY_STROKE_CONTROL , saved ) ; }
target:  Draws a line perpendicular to the range axis.