<div jsfc="custom:tree" id="tree" value="#{treeTable.treeModel}" var="node">...</div>

<facelet-taglib>
  <namespace>http://www.mycompany.com/jsf</namespace>
  <tag>
    <tag-name>bar</tag-name>
    <component>
      <component-type>javax.faces.Data</component-type>
      <renderer-type>com.mycompany.Bar</renderer-type>
    </component>
  </tag>
</facelet-taglib>

 public   final   class  IfHandler  extends  TagHandler {

     protected   final  TagAttribute test;
     protected   final  TagAttribute var;

     public  IfHandler(TagConfig config) {
         super (config);
         this .test =  this .getRequiredAttribute("test");
         this .var =  this .getAttribute("var");
    }

     public   void  apply(FaceletContext ctx, UIComponent parent)
             throws  IOException, FacesException, ELException {
         boolean  b =  this .test.getBoolean(ctx);
         if  ( this .var !=  null ) {
            ctx.setAttribute(var.getValue(ctx),  new   Boolean (b));
        }
         if  (b) {
             this .nextHandler.apply(ctx, parent);
        }
    }
}
<facelet-taglib>
  <namespace>http://www.jsfcentral.com/public</namespace>
  <tag>
    <tag-name> if </tag-name>
    <handler- class >com.jsfcentral.IfHandler</handler- class >
  </tag>
</facelet-taglib>