/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.runtime.heartbeat;

import org.apache.flink.runtime.clusterframework.types.ResourceID;

/**
 * A heartbeat manager has to be able to do the following things:
 *
 * <ul>
 *     <li>Monitor {@link HeartbeatTarget} and report heartbeat timeouts for this target</li>
 *     <li>Stop monitoring a {@link HeartbeatTarget}</li>
 * </ul>
 *
 *
 * @param <I> Type of the incoming payload
 * @param <O> Type of the outgoing payload
 */
public interface HeartbeatManager<I, O> extends HeartbeatTarget<I> {

	/**
	 * Start monitoring a {@link HeartbeatTarget}. Heartbeat timeouts for this target are reported
	 * to the {@link HeartbeatListener} associated with this heartbeat manager.
	 *
	 * @param resourceID Resource ID identifying the heartbeat target
	 * @param heartbeatTarget Interface to send heartbeat requests and responses to the heartbeat
	 *                        target
	 */
	void monitorTarget(ResourceID resourceID, HeartbeatTarget<O> heartbeatTarget);

	/**
	 * Stops monitoring the heartbeat target with the associated resource ID.
	 *
	 * @param resourceID Resource ID of the heartbeat target which shall no longer be monitored
	 */
	void unmonitorTarget(ResourceID resourceID);

	/**
	 * Stops the heartbeat manager.
	 */
	void stop();
}