geode-core/src/main/java/org/apache/geode/internal/cache/persistence/PersistentMemberView.java

/*
 * 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.geode.internal.cache.persistence;

import java.util.Set;

import org.apache.geode.internal.cache.LocalRegion;

/**
 * Holds a view of the persistent members for a region. This view may be backed by disk, or it may
 * be only in memory on non-persistent replicas.
 *
 *
 */
public interface PersistentMemberView {

  /**
   * @return the set of online members.
   */
  Set<PersistentMemberID> getOnlineMembers();

  /**
   * @return the set of offline members
   */
  Set<PersistentMemberID> getOfflineMembers();

  /**
   * @return the set of offline and equal members
   */
  Set<PersistentMemberID> getOfflineAndEqualMembers();

  /**
   * Retrieve the persisted ID of the current member.
   */
  PersistentMemberID getMyPersistentID();

  /**
   * Indicate that this member is now online, and initialize it with the list of offline and online
   * members.
   */
  void setInitialized();

  /**
   * Indicate that a member is offline. This is only called after this member is online.
   */
  void memberOffline(PersistentMemberID persistentID);

  /**
   * Indicate that a member is offline, and has the same data on disk as the current member. This is
   * only called after this member is online.
   */
  void memberOfflineAndEqual(PersistentMemberID persistentID);

  /**
   * Indicate that a new member is online. This is only called after this member is online.
   */
  void memberOnline(PersistentMemberID persistentID);

  /**
   * Indicate that the member no longer persists the region and can be removed. This is only called
   * after this member is online.
   *
   */
  void memberRemoved(PersistentMemberID persistentID);

  PersistentMemberID generatePersistentID();

  void setInitializing(PersistentMemberID newId);

  /**
   * Indicate that we are about to destroy this region. This method will be called before
   * distribution so that if we crash during distribution, we can recover and complete the destroy.
   * It will remove all data from disk for this region and remove the membership view. It must keep
   * the PersistentID.
   */
  void beginDestroy(LocalRegion region);

  /**
   * Indicate that we are about to partially destroy this region. It is used to stop hosting a
   * bucket and become a proxy bucket. This method will be called before distribution so that if we
   * crash during distribution, we can recover and complete the partial destroy. It will remove all
   * data from disk for this region. It must keep the PersistentID and the membership view.
   */
  void beginDestroyDataStorage();

  /**
   * This method is called to finish either setAboutToDestroy or setAboutToPartialDestroy.
   *
   * It can be called either during a normal region destroy or during a partial region destroy.
   * AFTER distribution has completed or during initialization IF the region was previously crashed
   * while it was "about to destroy." This method is expected to purge any data on disk, as well as
   * any membership view information and persistent ID for this region.
   *
   *
   * This method should NOT prevent this disk region from being initialized later.
   */
  void endDestroy(LocalRegion region);

  PersistentMemberID getMyInitializingID();

  boolean wasAboutToDestroy();

  boolean wasAboutToDestroyDataStorage();

  /**
   * This method is used to complete a destroy that was pending when a member crashed. This method
   * applies the destroy operation, but it leaves the DiskRegion in a usable (empty) state.
   */
  void finishPendingDestroy();

  DiskStoreID getDiskStoreID();

  void memberRevoked(PersistentMemberPattern pattern);

  Set<PersistentMemberPattern> getRevokedMembers();
}