MyInterceptor.java

public class MyInterceptor extends AbstractInterceptor {
    private static PrintStream log;
    static {
        try {
            final File f = new File("/tmp/moquette-subscribe-events.log");
            log = new PrintStream(f);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void handleIntercept(InterceptEvent evt) {
        final AbstractMessage msg = ((ProtocolEvent) evt.getEvent()).getMessage();

        if (msg instanceof PublishMessage) {
            log.printf("PUB: %s\n", ((PublishMessage) msg).getTopicName());
            try {
                Thread.sleep(5000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        evt.executeHook();
    }
}