protected List<Mirror.Entry> lookup(RoutingContext context, String pattern) {
        IMirror mirror1 =  context.getMirror();

        List<Mirror.Entry> arr = mirror1.lookup(pattern);

        if (arr.isEmpty()) {
            synchronized(this)  {
                if (firstTry) {
                    try {
                        int count = 0;
                        while (arr.isEmpty() && count < 100) {
                            Thread.sleep(50);
                            arr = mirror1.lookup(pattern);
                            count++;
                        }
                    } catch (InterruptedException e) {
                    }
                    firstTry = false;
                }
            }
        }

        return arr;
    }
Abstract class for policies that allow you to specify which slobrok to use for the routing.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/SlobrokPolicy.java