Robotics Service Bus

Since the Thread is not set to null activating will always lead to "already active" errors.

public class SingleThreadEventReceivingStrategy implements
        EventReceivingStrategy {

// ...

    @Override
    public void activate() {
        synchronized (this) {
            if (this.thread != null) {
                throw new IllegalStateException("Already activated."); // <-- This path is taken.
            }
            this.thread = new DispatchThread(this.events);
            this.thread.start();
        }
    }

    @Override
    public void deactivate() throws InterruptedException {
        synchronized (this) {
            if (this.thread == null) {
                throw new IllegalStateException("Already deactivated.");
            }
            this.thread.interrupt();
            this.thread.join();
            // here we should: this.thread = null;
        }
    }

// ...
}

Small example to produce error:

        Listener listener = rsb.Factory.getInstance().createListener(new Scope("/"));

        listener.activate();

        listener.deactivate();

        listener.activate(); // <--- Death to all who reach this point!!!! Whohahah

        listener.deactivate();

        System.exit(0);