Arcgis for JavaScript如何根据图形Graphic范围大小自动缩放在地图上显示

arcgis for JavaScript
如何根据esri.Graphic在地图esri.Map上根据图形的范围大小来自动缩放级别呢？

此问题已解决，代码如下：
var symbol = new esri.symbol.SimpleFillSymbol(esri.symbol.SimpleFillSymbol.STYLE_SOLID, new esri.symbol.SimpleLineSymbol(esri.symbol.SimpleLineSymbol.STYLE_SOLID, new dojo.Color([ 255, 255, 255, 0.35 ]), 1), new dojo.Color([ 125, 125, 125, 0.35 ]));
judgeCircle = new esri.geometry.Circle({
center : pointCenter,
geodesic : true,
radius : valuerd * 1000
});
var graphicCrile = new esri.Graphic(judgeCircle, symbol);
map.setExtent(judgeCircle.getExtent());