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     */
018    
019    package org.apache.hadoop.hdfs.inotify;
020    
021    import org.apache.hadoop.classification.InterfaceAudience;
022    import org.apache.hadoop.classification.InterfaceStability;
023    
024    @InterfaceAudience.Public
025    @InterfaceStability.Evolving
026    public class MissingEventsException extends Exception {
027      private static final long serialVersionUID = 1L;
028    
029      private long expectedTxid;
030      private long actualTxid;
031    
032      public MissingEventsException() {}
033    
034      public MissingEventsException(long expectedTxid, long actualTxid) {
035        this.expectedTxid = expectedTxid;
036        this.actualTxid = actualTxid;
037      }
038    
039      public long getExpectedTxid() {
040        return expectedTxid;
041      }
042    
043      public long getActualTxid() {
044        return actualTxid;
045      }
046    
047      @Override
048      public String toString() {
049        return "We expected the next batch of events to start with transaction ID "
050            + expectedTxid + ", but it instead started with transaction ID " +
051            actualTxid + ". Most likely the intervening transactions were cleaned "
052            + "up as part of checkpointing.";
053      }
054    }