helix-core/src/main/java/org/apache/helix/examples/SegmentOnlineOfflineStateModelFactory.java

package org.apache.helix.examples;

import org.apache.helix.NotificationContext;
import org.apache.helix.model.Message;
import org.apache.helix.participant.statemachine.StateModel;
import org.apache.helix.participant.statemachine.StateModelFactory;
import org.apache.helix.participant.statemachine.StateModelInfo;
import org.apache.helix.participant.statemachine.Transition;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SegmentOnlineOfflineStateModelFactory extends StateModelFactory<StateModel> {
  public SegmentOnlineOfflineStateModelFactory() {
  }

  @Override
  public StateModel createNewStateModel(String partitionName) {
    final SegmentOnlineOfflineStateModel SegmentOnlineOfflineStateModel = new SegmentOnlineOfflineStateModel();
    return SegmentOnlineOfflineStateModel;
  }

  @StateModelInfo(states = "{'OFFLINE','ONLINE', 'DROPPED'}", initialState = "OFFLINE")
  public static class SegmentOnlineOfflineStateModel extends StateModel {
    private static final Logger LOGGER = LoggerFactory.getLogger(SegmentOnlineOfflineStateModel.class);

    @Transition(from = "OFFLINE", to = "ONLINE")
    public void onBecomeOnlineFromOffline(Message message, NotificationContext context) {
      LOGGER.info("Become Online from Offline");
    }

    // Remove segment from InstanceDataManager.
    // Still keep the data files in local.
    @Transition(from = "ONLINE", to = "OFFLINE")
    public void onBecomeOfflineFromOnline(Message message, NotificationContext context) {
      LOGGER.info("Become Offline from Online");

    }

    // Delete segment from local directory.
    @Transition(from = "OFFLINE", to = "DROPPED")
    public void onBecomeDroppedFromOffline(Message message, NotificationContext context) {
      LOGGER.info("Become Dropped from Offline");

    }

    @Transition(from = "ONLINE", to = "DROPPED")
    public void onBecomeDroppedFromOnline(Message message, NotificationContext context) {
      LOGGER.info("Become Dropped from Online");

    }
  }

}