[stringtemplate-interest] StringTemplateGroup attribute renderer bug + fix

[Terence Parr]

On Oct 14, 2005, at 1:49 AM, VAUCHER Laurent wrote:
>   This morning (UTC+1) I tried to add my own AttributeRenderer to a
> StringTemplateGroup, and had the unpleasant suprise to receive a
> NullPointerException. After reading the code, it seems that a group
> where one attribute renderer is registered must either define renderes
> for all possible attribute types, or have a super group that does. I
> would have thought that in this case, the standard default renderer
> would be used, and since the result is an NPE, it might only be an
> edge-case that escaped.

Ack!  Sorry about that.  It's a bug...fixing now.

>
>   Therefore, I successfully made a patch to StringTemplateGroup.java,
> around line 594 :
>
>
>     if ( renderer==null ) {
> +        if ( superGroup==null ) {
> +            return null; // no parent?  Stop.
> +        }
>         // no renderer registered for this class, check super
> group
>         renderer =
> superGroup.getAttributeRenderer(attributeClassType);
>     }

I did it slightly differently:

         if ( renderer==null ) {
             if ( superGroup!=null ) {
                 // no renderer registered for this class, check  
super group
                 renderer = superGroup.getAttributeRenderer 
(attributeClassType);
             }
         }

Anyway, thanks!

Ter