org.apache.spark.deploy.master.LeaderElectionAgent.scala Maven / Gradle / Ivy
/*
* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.spark.deploy.master
import org.apache.spark.annotation.DeveloperApi
/**
* :: DeveloperApi ::
*
* A LeaderElectionAgent tracks current master and is a common interface for all election Agents.
*/
@DeveloperApi
trait LeaderElectionAgent {
val masterInstance: LeaderElectable
def stop() {} // to avoid noops in implementations.
}
@DeveloperApi
trait LeaderElectable {
def electedLeader(): Unit
def revokedLeadership(): Unit
}
/** Single-node implementation of LeaderElectionAgent -- we're initially and always the leader. */
private[spark] class MonarchyLeaderAgent(val masterInstance: LeaderElectable)
extends LeaderElectionAgent {
masterInstance.electedLeader()
}