code: function LineNumberRuler (annotationModel, rulerLocation, rulerStyle, oddStyle, evenStyle) {
  		Ruler.call(this, annotationModel, rulerLocation, "page", rulerStyle); //$NON-NLS-0$
  		this._oddStyle = oddStyle || {style: {backgroundColor: "white"}}; //$NON-NLS-0$
  		this._evenStyle = evenStyle || {style: {backgroundColor: "white"}}; //$NON-NLS-0$
  		this._numOfDigits = 0;
  		this._firstLine = 1;
  	}
docs: Constructs a new line numbering ruler.
  
  @param {orion.editor.AnnotationModel} annotationModel the annotation model for the ruler.
  @param {String} [rulerLocation="left"] the location for the ruler.
  @param {orion.editor.Style} [rulerStyle=undefined] the style for the ruler.
  @param {orion.editor.Style} [oddStyle={style: {backgroundColor: "white"}] the style for lines with odd line index.
  @param {orion.editor.Style} [evenStyle={backgroundColor: "white"}] the style for lines with even line index.
  
  @augments orion.editor.Ruler
  @class This objects implements a line numbering ruler.
  
  <p><b>See:</b><br/>
  {@link orion.editor.Ruler}
  </p>
  @name orion.editor.LineNumberRuler