com.hazelcast.internal.cluster.fd.FailureDetector Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.internal.cluster.fd;
/**
* Failure detector tracks heartbeats of a member and decides liveness/availability of the member.
*/
public interface FailureDetector {
/**
* Notifies this failure detector about received heartbeat message from the tracked member.
*
* @param timestamp timestamp of heartbeat message in milliseconds
*/
void heartbeat(long timestamp);
/**
* Returns true if the tracked member is considered as alive/available.
* @param timestamp timestamp in milliseconds
* @return true if the member is alive
*/
boolean isAlive(long timestamp);
/**
* Returns the last heartbeat timestamp for the tracked member.
* @return heartbeat timestamp in milliseconds
*/
long lastHeartbeat();
/**
* Returns suspicion level about the tracked member. Returned value is mostly implementation dependent.
* 0 indicates no suspicion at all.
* @param timestamp timestamp in milliseconds
* @return suspicion level
*/
double suspicionLevel(long timestamp);
}