/*
 * Copyright 2014 Open Networking Laboratory
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.onlab.onos.cluster;

/**
 * Service for obtaining information about the leader election.
 */
public interface LeadershipService {

    /**
     * Returns the current leader controller node.
     *
     * @return current leader controller node
     */
    ControllerNode getLeader();

    /**
     * Adds the specified leadership event listener.
     *
     * @param listener the leadership listener
     */
    void addListener(LeadershipEventListener listener);

    /**
     * Removes the specified leadership event listener.
     *
     * @param listener the leadership listener
     */
    void removeListener(LeadershipEventListener listener);

}