Laserscan subscription delay! rosjava on android

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Hello,

I am currently working on an android application for visualization of sensor data. During my first test projects I encountered a serious delay in messages caused by message deserialization of the LaserScan messages (at 40Hz).

The only way I could solve the delay issues was to inhert from the the private Receiver class in IncomingMessageQueue.java of rosjava and have the new class RateReceiver, ignore message when it falls below a rate threshold (code attached).

I am now searching for a way to augment rosjava / the android framework to use my code. After i researched the instantiation hierarchy of Receiver < IncomingMessageQueue < Subscriber < SubscriberFactory < DefaultNode I was wondering what is the best way to subclass and integrate my code? Currently the SubscriberFactory cannot be changed via the NodeConfiguration class (but there was a TODO in the code related to future configuration options? -> DefaultNode.java:89) Are there any plans regarding a custom Subscriber(Factory) class?

Or is there even a better way to solve that delay problem? (If i remember correctly I had also delays with receiving camera images)

(As for hardware: The code runs on a Asus Transformer Prime with Tegra3 1.4GHz quad and 1GB of ram, Android 4.0.3)

I hope someone can help me, and thank you in advance!

Regards, Sebastian

private final class RateReceiver extends Receiver {

    private int count;
    private double time;
    private double curRate;
    private double refRate;
    private double tolerance;
    private int window;

    public RateReceiver(double rate, double tolerance, int window) {
        this.refRate = rate;
        this.tolerance = tolerance;
        this.window = window;
    }

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
            throws Exception {

        count++;
        if (count % window == 0) {
            // Reset measurement
            count = 0;
            time = System.currentTimeMillis() / 1000;
        } else {
            // Calculate rate
            curRate = count / (System.currentTimeMillis() / 1000 - time);
        }

        if (count % refRate == 0) { 
            System.err.println("receive rate " + curRate);
        }

        // Only process messages when inside tolerance
        if (curRate > refRate - tolerance) {
            super.messageReceived(ctx, e);
        }
    }
}