private void resolvePlaceholders() {
        try {
            PlaceholderMappingVisitor placeholderMappingVisitor=new PlaceholderMappingVisitor();
            accept(placeholderMappingVisitor);
            accept(new PlaceholderReferenceCreatingVisitor(placeholderMappingVisitor.getMap()));
        }
        catch (IllegalArgumentException e) {
            throw new IllegalArgumentException(this + " is invalid",e);
        }
    }
Validates and creates the necessary internal references between placeholders and their resolving choices
container-search/src/main/java/com/yahoo/search/pagetemplates/PageTemplate.java