@Override
    public List<Mirror.Entry> lookup(ApplicationId id, String pattern) {
        synchronized (monitor) {
            SlobrokMonitor slobrokMonitor = slobrokMonitors.get(id);
            if (slobrokMonitor == null) {
                throw new IllegalArgumentException("Slobrok manager has no knowledge of application " + id);
            } else {
                return slobrokMonitor.lookup(pattern);
            }
        }
    }
@Test
    public void testLookup() {
        assertEquals(
                Optional.of("vespa/service/config.id"),
                findSlobrokServiceName("container", "config.id"));

        assertEquals(
                Optional.empty(),
                findSlobrokServiceName("logserver", "config.id"));
    }