/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.cluster.coordination;

import org.elasticsearch.action.ActionListener;
import org.elasticsearch.cluster.node.DiscoveryNode;

public interface LeaderHeartbeatService {
    LeaderHeartbeatService NO_OP = new LeaderHeartbeatService() {
        @Override
        public void start(DiscoveryNode currentLeader, long term, ActionListener<Long> completionListener) {}

        @Override
        public void stop() {}
    };

    /**
     * Start a heartbeat process for the given term. The listener is notified when the heartbeat process completes, which may happen if
     * it fails to write a heartbeat, or a newer term is discovered.
     */
    void start(DiscoveryNode currentLeader, long term, ActionListener<Long> completionListener);

    void stop();
}