question: public void drawRangeMarker ( Graphics2D g2 , ContourPlot plot , ValueAxis rangeAxis , Marker marker , Rectangle2D dataArea ) { if ( marker instanceof ValueMarker ) { ValueMarker vm = ( ValueMarker ) marker ; double value = vm . getValue ( ) ; Range range = rangeAxis . getRange ( ) ; if ( ! range . contains ( value ) ) { return ; } double y = rangeAxis . valueToJava2D ( value , dataArea , RectangleEdge . LEFT ) ; Line2D line = new Line2D . Double ( dataArea . getMinX ( ) , y , dataArea . getMaxX ( ) , y ) ; Paint paint = marker . getOutlinePaint ( ) ; Stroke stroke = marker . getOutlineStroke ( ) ; g2 . setPaint ( paint != null ? paint : Plot . DEFAULT_OUTLINE_PAINT ) ; g2 . setStroke ( stroke != null ? stroke : Plot . DEFAULT_OUTLINE_STROKE ) ; g2 . draw ( line ) ; } }
target:  Draws a horizontal line across the chart to represent a 'range marker'.