DOSGi Discovery Demo page

This page describes the demo that shows the Discovery functionality of Distributed OSGi.

It assumes that you have set up your DOSGi/ZooKeeper based Discovery system as outlined in DOSGi Discovery.
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Demo design

This demo contains of a display controller node that writes messages on all the available display instances. Display instances are realized as remote OSGi services, which are registered with the ZooKeeper-based Discovery system. The discovery system informs the controller, which is a consumer of the DisplayService, of any available remote instances of this service.
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As with most of the other demos, the actual implementation consists of 3 bundles.

• A DisplayService interface bundle.
• A DisplayService implementation bundle.
• A DisplayService client bundle, which takes the role of the display controller.

The Display Service interface is like this:

public interface DisplayService {
    boolean displayText(String text);
    String getID();
}

The Display Service Controller

Let's start with the controller, which is a consumer to the the DisplayService. It's simply using an OSGi ServiceTracker to consume all DisplayService services. It uses a Scheduled Executor to periodically send test messages to all registered displays.