public PluginImpl getByPath(String[] url , int n){
		if(url.length -1 == n){
			for(UrlNode childNode: this.childNodes){
				if(childNode.selfUrl.equals(url[n])){
					return childNode.pluginNode ;
				}
			}
			return null ;
		}else{
			for(UrlNode node : childNodes){
				if(node.selfUrl.equals(url[n])){
					PluginImpl pluginImpl = node.getByPath(url, n+1) ;
					if( pluginImpl != null) 
						return pluginImpl ;
					else 
						return node.pluginNode ;
				}
			}
		}
		return null ;
	}