hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/qjournal/client/TestSegmentRecoveryComparator.java

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 * 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
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package org.apache.hadoop.hdfs.qjournal.client;

import static org.junit.Assert.*;

import java.util.Map;
import java.util.Map.Entry;

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PrepareRecoveryResponseProto;
import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.SegmentStateProto;
import org.junit.Test;
import org.mockito.Mockito;

import com.google.common.collect.Maps;

import static org.apache.hadoop.hdfs.qjournal.client.SegmentRecoveryComparator.INSTANCE;

public class TestSegmentRecoveryComparator {
  
  private static Map.Entry<AsyncLogger, PrepareRecoveryResponseProto> makeEntry(
      PrepareRecoveryResponseProto proto) {
    return Maps.immutableEntry(Mockito.mock(AsyncLogger.class), proto);
  }
  
  @Test
  public void testComparisons() {
    Entry<AsyncLogger, PrepareRecoveryResponseProto> INPROGRESS_1_3 =
        makeEntry(PrepareRecoveryResponseProto.newBuilder()
          .setSegmentState(SegmentStateProto.newBuilder()
              .setStartTxId(1L)
              .setEndTxId(3L)
              .setIsInProgress(true))
          .setLastWriterEpoch(0L)
          .build());
    Entry<AsyncLogger, PrepareRecoveryResponseProto> INPROGRESS_1_4 =
        makeEntry(PrepareRecoveryResponseProto.newBuilder()
          .setSegmentState(SegmentStateProto.newBuilder()
              .setStartTxId(1L)
              .setEndTxId(4L)
              .setIsInProgress(true))
          .setLastWriterEpoch(0L)
          .build());
    Entry<AsyncLogger, PrepareRecoveryResponseProto> INPROGRESS_1_4_ACCEPTED =
        makeEntry(PrepareRecoveryResponseProto.newBuilder()
          .setSegmentState(SegmentStateProto.newBuilder()
              .setStartTxId(1L)
              .setEndTxId(4L)
              .setIsInProgress(true))
          .setLastWriterEpoch(0L)
          .setAcceptedInEpoch(1L)
          .build());

    Entry<AsyncLogger, PrepareRecoveryResponseProto> FINALIZED_1_3 =
        makeEntry(PrepareRecoveryResponseProto.newBuilder()
          .setSegmentState(SegmentStateProto.newBuilder()
              .setStartTxId(1L)
              .setEndTxId(3L)
              .setIsInProgress(false))
          .setLastWriterEpoch(0L)
          .build());

    // Should compare equal to itself
    assertEquals(0, INSTANCE.compare(INPROGRESS_1_3, INPROGRESS_1_3));
    
    // Longer log wins.
    assertEquals(-1, INSTANCE.compare(INPROGRESS_1_3, INPROGRESS_1_4));
    assertEquals(1, INSTANCE.compare(INPROGRESS_1_4, INPROGRESS_1_3));
    
    // Finalized log wins even over a longer in-progress
    assertEquals(-1, INSTANCE.compare(INPROGRESS_1_4, FINALIZED_1_3));
    assertEquals(1, INSTANCE.compare(FINALIZED_1_3, INPROGRESS_1_4));

    // Finalized log wins even if the in-progress one has an accepted
    // recovery proposal.
    assertEquals(-1, INSTANCE.compare(INPROGRESS_1_4_ACCEPTED, FINALIZED_1_3));
    assertEquals(1, INSTANCE.compare(FINALIZED_1_3, INPROGRESS_1_4_ACCEPTED));
  }
}