package org.apache.helix.participant;
/*
* 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.
*/
import java.util.List;
import org.apache.helix.HelixManager;
import org.apache.helix.NotificationContext;
import org.apache.helix.HelixConstants.ChangeType;
import org.apache.helix.model.Message;
import org.apache.helix.participant.statemachine.StateModel;
import org.apache.helix.participant.statemachine.StateModelInfo;
import org.apache.helix.participant.statemachine.Transition;
import org.apache.log4j.Logger;
@StateModelInfo(initialState = "OFFLINE", states = { "LEADER", "STANDBY" })
public class GenericLeaderStandbyModel extends StateModel
{
private static Logger LOG = Logger.getLogger(GenericLeaderStandbyModel.class);
private final CustomCodeInvoker _particHolder;
private final List<ChangeType> _notificationTypes;
public GenericLeaderStandbyModel(CustomCodeCallbackHandler callback,
List<ChangeType> notificationTypes,
String partitionKey)
{
_particHolder = new CustomCodeInvoker(callback, partitionKey);
_notificationTypes = notificationTypes;
}
@Transition(to="STANDBY",from="OFFLINE")
public void onBecomeStandbyFromOffline(Message message, NotificationContext context)
{
LOG.info("Become STANDBY from OFFLINE");
}
@Transition(to="LEADER",from="STANDBY")
public void onBecomeLeaderFromStandby(Message message, NotificationContext context)
throws Exception
{
LOG.info("Become LEADER from STANDBY");
HelixManager manager = context.getManager();
if (manager == null)
{
throw new IllegalArgumentException("Require HelixManager in notification conext");
}
for (ChangeType notificationType : _notificationTypes)
{
if (notificationType == ChangeType.LIVE_INSTANCE)
{
manager.addLiveInstanceChangeListener(_particHolder);
}
else if (notificationType == ChangeType.CONFIG)
{
manager.addConfigChangeListener(_particHolder);
}
else if (notificationType == ChangeType.EXTERNAL_VIEW)
{
manager.addExternalViewChangeListener(_particHolder);
}
else
{
LOG.error("Unsupport notificationType:" + notificationType.toString());
}
}
}
@Transition(to="STANDBY",from="LEADER")
public void onBecomeStandbyFromLeader(Message message, NotificationContext context)
{
LOG.info("Become STANDBY from LEADER");
HelixManager manager = context.getManager();
manager.removeListener(_particHolder);
}
@Transition(to="OFFLINE",from="STANDBY")
public void onBecomeOfflineFromStandby(Message message, NotificationContext context)
{
LOG.info("Become OFFLINE from STANDBY");
}
}