Interfaces for leader election / retrieval in mantis

[sundargates]

Spec for High Availability Services:

public interface LeaderRetrieval {
    /**
     * Starts the leader retrieval process.
     * 
     * @throws Exception if an error occurs while starting the election
     */
    void start() throws Exception;

    /**
     * Stops the leader retrieval process.
     * 
     * @throws Exception if an error occurs while stopping the election
     */
    void stop() throws Exception;

    Listenable<Listener> getListenable();

   @Nullable
    byte[] getLeader();

    interface Listener {
        void onLeaderChanged(@Nullable byte[] leader);
    }
}

public interface LeaderElection {
    
    /**
     * Starts the leader election process.
     * 
     * @throws Exception if an error occurs while starting the election
     */
    void start() throws Exception;

    /**
     * Stops the leader election process.
     * 
     * @throws Exception if an error occurs while stopping the election
     */
    void stop() throws Exception;

    /**
     * Checks if the current instance is the leader.
     * 
     * @return true if the current instance is the leader, false otherwise
     */
    boolean isLeader();
    
    /**
     * Sets a listener for leader election events.
     *
     * @param listener the listener to notify when leadership changes
     */
    Listenable<LeaderElectionListener> getListenable();

    interface LeaderElectionListener {
        void onElectedLeader();
        void onRevokedLeadership();
    }
}

application.properties:

io.mantisrx.highavailability.leader-election: className1
io.mantisrx.highavailability.leader-retrieval: className2

[sundargates]

@Andyz26 @mcowgill-stripe Can you guys take a look at this spec for leader election/retrieval?