docs: static protected String extractTemplateUrl(String viewName){
  		int i1 = -1;
  		int i2 = -1;
  		int i3 = -1;
  		int i4 = -1;
  		i1 = viewName.indexOf(LEFT_BRACKET);
  		if (i1 != -1){
  			i2 = viewName.indexOf(LEFT_BRACKET, i1+1);
  		}
  		i4 = viewName.lastIndexOf(RIGHT_BRACKET);
  		if (i4 != -1){
  			i3 = viewName.lastIndexOf(RIGHT_BRACKET, i4-1);
  		}
  		
  		if ((i1 == -1 || i4 == -1)		// no starting or ending 
  				|| (i2*i3 < 0) 			// not matching
  				|| (i2 > i3)){			// not matching
  			return viewName;		// no valid template descriptor
  		}
  		
  		//////// the format is guaranteed to be valid after this point
  		
  		String url = null;
  		
  		if (i2 != -1){
  			url = viewName.substring(i1+1, i2);		// prefix{url{...}}postfix
  		}else{
  			url = viewName.substring(i1+1, i4);		// prefix{url}postfix
  		}
  
  		if (i1 > 0){
  			String prefix = viewName.substring(0, i1);
  			url = prefix + url;
  		}
  		if (i4 < viewName.length() - 1){
  			String postfix = viewName.substring(i4 + 1);
  			url = url + postfix;
  		}
  		
  		return url;
  	}