protected void startCacheInvalidator() {
        polling = true;
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                // Wait for 30s on startup before starting to poll.
                try { Thread.sleep(startupDelayMillis); } catch (InterruptedException e1) { e1.printStackTrace(); }

                while (polling) {
                    try {
                        Thread.sleep(pollIntervalMillis);
                        checkCacheVersion();
                    } catch (Exception e) {
                        LOGGER.error(e.getMessage(), e);
                    }

                }
            }
        }, "EsRegistryCacheInvalidator"); //$NON-NLS-1$
        thread.setDaemon(true);
        thread.start();
    }
Starts up a thread that polls the ES store for updates.
gateway/engine/es/src/main/java/io/apiman/gateway/engine/es/PollCachingEsRegistry.java