balboa-backend-java

This is a balboa backend connector for Java. It takes care of the boring msgpack deserialization and validation, and provides a pluggable interface for backends to receive input and answer queries.

Interaction with the frontend(s) is done via code implementing the InputProcessor interface, which is called for each incoming message. The methods to be implemented refer to the various message types:

@FunctionalInterface
public interface ObservationStreamConsumer
{
    void submit(Observation o) throws IOException;
}

public interface InputProcessor {
    public abstract void handle(Observation o) throws BalboaException;
    public abstract void handle(DumpRequest d) throws BalboaException;
    public abstract void handle(BackupRequest b) throws BalboaException;
    public abstract void handle(Query q, ObservationStreamConsumer submitResult) throws BalboaException, IOException;
    public abstract void close();
}

Here's the simplest forking server that starts a new processing engine for each new incoming connection and just prints incoming mesages:

public class Main {
    public static void main(String[] args) {
        ServerSocket server = new ServerSocket(4242);
        do {
            Socket socket = server.accept();
            new Thread(new BackendWorker(socket, new PrintProcessor())).start();
        } while (true);
    }
}