001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.master;
019
020import org.apache.yetus.audience.InterfaceAudience;
021import org.apache.yetus.audience.InterfaceStability;
022import org.apache.hadoop.hbase.errorhandling.ForeignException;
023import org.apache.hadoop.hbase.shaded.protobuf.generated.SnapshotProtos.SnapshotDescription;
024
025/**
026 * Watch the current snapshot under process
027 */
028@InterfaceAudience.Private
029@InterfaceStability.Unstable
030public interface SnapshotSentinel {
031
032  /**
033   * Check to see if the snapshot is finished, where finished may be success or failure.
034   * @return <tt>false</tt> if the snapshot is still in progress, <tt>true</tt> if the snapshot has
035   *         finished
036   */
037  boolean isFinished();
038
039  /**
040   * @return -1 if the snapshot is in progress, otherwise the completion timestamp.
041   */
042  long getCompletionTimestamp();
043
044  /**
045   * Actively cancel a running snapshot.
046   * @param why Reason for cancellation.
047   */
048  void cancel(String why);
049
050  /**
051   * @return the description of the snapshot being run
052   */
053  SnapshotDescription getSnapshot();
054
055  /**
056   * Get the exception that caused the snapshot to fail, if the snapshot has failed.
057   * @return {@link ForeignException} that caused the snapshot to fail, or <tt>null</tt> if the
058   *  snapshot is still in progress or has succeeded
059   */
060  ForeignException getExceptionIfFailed();
061
062  /**
063   * Rethrow the exception returned by {@link SnapshotSentinel#getExceptionIfFailed}.
064   * If there is no exception this is a no-op.
065   *
066   * @throws ForeignException all exceptions from remote sources are procedure exceptions
067   */
068  void rethrowExceptionIfFailed() throws ForeignException;
069}