/**
    * Copyright The Apache Software Foundation
    *
    * 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.hadoop.hbase.regionserver;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertFalse;
  import static org.junit.Assert.assertTrue;
  import static org.mockito.Mockito.*;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CoordinatedStateManager;
  import org.apache.hadoop.hbase.CoordinatedStateManagerFactory;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Durability;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Scan;
  import org.apache.hadoop.hbase.testclassification.SmallTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.wal.WALFactory;
  import org.apache.zookeeper.KeeperException;
  import org.junit.After;
  import org.junit.Before;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.mockito.Mockito;
  
  import com.google.common.collect.ImmutableList;
  
  /**
   * Test the {@link RegionMergeTransactionImpl} class against two HRegions (as
   * opposed to running cluster).
   */
  @Category(SmallTests.class)
  public class TestRegionMergeTransaction {
    private final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private final Path testdir = TEST_UTIL.getDataTestDir(this.getClass()
        .getName());
    private HRegion region_a;
    private HRegion region_b;
    private HRegion region_c;
    private WALFactory wals;
    private FileSystem fs;
    // Start rows of region_a,region_b,region_c
    private static final byte[] STARTROW_A = new byte[] { 'a', 'a', 'a' };
    private static final byte[] STARTROW_B = new byte[] { 'g', 'g', 'g' };
    private static final byte[] STARTROW_C = new byte[] { 'w', 'w', 'w' };
    private static final byte[] ENDROW = new byte[] { '{', '{', '{' };
    private static final byte[] CF = HConstants.CATALOG_FAMILY;
  
    @Before
    public void setup() throws IOException {
      this.fs = FileSystem.get(TEST_UTIL.getConfiguration());
      this.fs.delete(this.testdir, true);
      final Configuration walConf = new Configuration(TEST_UTIL.getConfiguration());
      FSUtils.setRootDir(walConf, this.testdir);
      this.wals = new WALFactory(walConf, null, TestRegionMergeTransaction.class.getName());
      this.region_a = createRegion(this.testdir, this.wals, STARTROW_A, STARTROW_B);
      this.region_b = createRegion(this.testdir, this.wals, STARTROW_B, STARTROW_C);
      this.region_c = createRegion(this.testdir, this.wals, STARTROW_C, ENDROW);
      assert region_a != null && region_b != null && region_c != null;
      TEST_UTIL.getConfiguration().setBoolean("hbase.testing.nocluster", true);
    }
  
    @After
    public void teardown() throws IOException {
      for (HRegion region : new HRegion[] { region_a, region_b, region_c }) {
        if (region != null && !region.isClosed()) region.close();
        if (this.fs.exists(region.getRegionFileSystem().getRegionDir())
            && !this.fs.delete(region.getRegionFileSystem().getRegionDir(), true)) {
         throw new IOException("Failed deleting of "
             + region.getRegionFileSystem().getRegionDir());
       }
     }
     if (this.wals != null) {
       this.wals.close();
     }
     this.fs.delete(this.testdir, true);
   }
 
   /**
    * Test straight prepare works. Tries to merge on {@link #region_a} and
    * {@link #region_b}
    * @throws IOException
    */
   @Test
   public void testPrepare() throws IOException {
     prepareOnGoodRegions();
   }
 
   private RegionMergeTransactionImpl prepareOnGoodRegions() throws IOException {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(region_a, region_b,
         false);
     RegionMergeTransactionImpl spyMT = Mockito.spy(mt);
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_a.getRegionInfo().getRegionName());
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_b.getRegionInfo().getRegionName());
     assertTrue(spyMT.prepare(null));
     return spyMT;
   }
 
   /**
    * Test merging the same region
    */
   @Test
   public void testPrepareWithSameRegion() throws IOException {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(this.region_a,
         this.region_a, true);
     assertFalse("should not merge the same region even if it is forcible ",
         mt.prepare(null));
   }
 
   /**
    * Test merging two not adjacent regions under a common merge
    */
   @Test
   public void testPrepareWithRegionsNotAdjacent() throws IOException {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(this.region_a,
         this.region_c, false);
     assertFalse("should not merge two regions if they are adjacent except it is forcible",
         mt.prepare(null));
   }
 
   /**
    * Test merging two not adjacent regions under a compulsory merge
    */
   @Test
   public void testPrepareWithRegionsNotAdjacentUnderCompulsory()
       throws IOException {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(region_a, region_c,
         true);
     RegionMergeTransactionImpl spyMT = Mockito.spy(mt);
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_a.getRegionInfo().getRegionName());
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_c.getRegionInfo().getRegionName());
     assertTrue("Since focible is true, should merge two regions even if they are not adjacent",
         spyMT.prepare(null));
   }
 
   /**
    * Pass a reference store
    */
   @Test
   public void testPrepareWithRegionsWithReference() throws IOException {
     HStore storeMock = Mockito.mock(HStore.class);
     when(storeMock.hasReferences()).thenReturn(true);
     when(storeMock.getFamily()).thenReturn(new HColumnDescriptor("cf"));
     when(storeMock.close()).thenReturn(ImmutableList.<StoreFile>of());
     this.region_a.stores.put(Bytes.toBytes(""), storeMock);
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(this.region_a,
         this.region_b, false);
     assertFalse(
         "a region should not be mergeable if it has instances of store file references",
         mt.prepare(null));
   }
 
   @Test
   public void testPrepareWithClosedRegion() throws IOException {
     this.region_a.close();
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(this.region_a,
         this.region_b, false);
     assertFalse(mt.prepare(null));
   }
 
   /**
    * Test merging regions which are merged regions and has reference in hbase:meta all
    * the same
    */
   @Test
   public void testPrepareWithRegionsWithMergeReference() throws IOException {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(region_a, region_b,
         false);
     RegionMergeTransactionImpl spyMT = Mockito.spy(mt);
     doReturn(true).when(spyMT).hasMergeQualifierInMeta(null,
         region_a.getRegionInfo().getRegionName());
     doReturn(true).when(spyMT).hasMergeQualifierInMeta(null,
         region_b.getRegionInfo().getRegionName());
     assertFalse(spyMT.prepare(null));
   }
 
   /**
    * Test RegionMergeTransactionListener
    */
   @Test public void testRegionMergeTransactionListener() throws Exception {
     RegionMergeTransactionImpl mt = new RegionMergeTransactionImpl(region_a, region_b,
         false);
     RegionMergeTransactionImpl spyMT = Mockito.spy(mt);
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_a.getRegionInfo().getRegionName());
     doReturn(false).when(spyMT).hasMergeQualifierInMeta(null,
         region_b.getRegionInfo().getRegionName());
     RegionMergeTransaction.TransactionListener listener =
             Mockito.mock(RegionMergeTransaction.TransactionListener.class);
     mt.registerTransactionListener(listener);
     mt.prepare(null);
     TEST_UTIL.getConfiguration().setInt(HConstants.REGIONSERVER_PORT, 0);
     CoordinatedStateManager cp = CoordinatedStateManagerFactory.getCoordinatedStateManager(
       TEST_UTIL.getConfiguration());
     Server mockServer = new HRegionServer(TEST_UTIL.getConfiguration(), cp);
     mt.execute(mockServer, null);
     verify(listener).transition(mt,
             RegionMergeTransaction.RegionMergeTransactionPhase.STARTED,
             RegionMergeTransaction.RegionMergeTransactionPhase.PREPARED);
     verify(listener, times(10)).transition(any(RegionMergeTransaction.class),
             any(RegionMergeTransaction.RegionMergeTransactionPhase.class),
             any(RegionMergeTransaction.RegionMergeTransactionPhase.class));
     verifyNoMoreInteractions(listener);
   }
 
   @Test
   public void testWholesomeMerge() throws IOException, InterruptedException {
     final int rowCountOfRegionA = loadRegion(this.region_a, CF, true);
     final int rowCountOfRegionB = loadRegion(this.region_b, CF, true);
     assertTrue(rowCountOfRegionA > 0 && rowCountOfRegionB > 0);
     assertEquals(rowCountOfRegionA, countRows(this.region_a));
     assertEquals(rowCountOfRegionB, countRows(this.region_b));
 
     // Start transaction.
     RegionMergeTransactionImpl mt = prepareOnGoodRegions();
 
     // Run the execute. Look at what it returns.
     TEST_UTIL.getConfiguration().setInt(HConstants.REGIONSERVER_PORT, 0);
     CoordinatedStateManager cp = CoordinatedStateManagerFactory.getCoordinatedStateManager(
       TEST_UTIL.getConfiguration());
     Server mockServer = new HRegionServer(TEST_UTIL.getConfiguration(), cp);
     HRegion mergedRegion = (HRegion)mt.execute(mockServer, null);
     // Do some assertions about execution.
     assertTrue(this.fs.exists(mt.getMergesDir()));
     // Assert region_a and region_b is closed.
     assertTrue(region_a.isClosed());
     assertTrue(region_b.isClosed());
 
     // Assert mergedir is empty -- because its content will have been moved out
     // to be under the merged region dirs.
     assertEquals(0, this.fs.listStatus(mt.getMergesDir()).length);
     // Check merged region have correct key span.
     assertTrue(Bytes.equals(this.region_a.getRegionInfo().getStartKey(),
         mergedRegion.getRegionInfo().getStartKey()));
     assertTrue(Bytes.equals(this.region_b.getRegionInfo().getEndKey(),
         mergedRegion.getRegionInfo().getEndKey()));
     // Count rows. merged region are already open
     try {
       int mergedRegionRowCount = countRows(mergedRegion);
       assertEquals((rowCountOfRegionA + rowCountOfRegionB),
           mergedRegionRowCount);
     } finally {
       HRegion.closeHRegion(mergedRegion);
     }
     // Assert the write lock is no longer held on region_a and region_b
     assertTrue(!this.region_a.lock.writeLock().isHeldByCurrentThread());
     assertTrue(!this.region_b.lock.writeLock().isHeldByCurrentThread());
   }
 
   @Test
   public void testRollback() throws IOException, InterruptedException {
     final int rowCountOfRegionA = loadRegion(this.region_a, CF, true);
     final int rowCountOfRegionB = loadRegion(this.region_b, CF, true);
     assertTrue(rowCountOfRegionA > 0 && rowCountOfRegionB > 0);
     assertEquals(rowCountOfRegionA, countRows(this.region_a));
     assertEquals(rowCountOfRegionB, countRows(this.region_b));
 
     // Start transaction.
     RegionMergeTransactionImpl mt = prepareOnGoodRegions();
 
     when(mt.createMergedRegionFromMerges(region_a, region_b,
         mt.getMergedRegionInfo())).thenThrow(
         new MockedFailedMergedRegionCreation());
 
     // Run the execute. Look at what it returns.
     boolean expectedException = false;
     TEST_UTIL.getConfiguration().setInt(HConstants.REGIONSERVER_PORT, 0);
     CoordinatedStateManager cp = CoordinatedStateManagerFactory.getCoordinatedStateManager(
       TEST_UTIL.getConfiguration());
     Server mockServer = new HRegionServer(TEST_UTIL.getConfiguration(), cp);
     try {
       mt.execute(mockServer, null);
     } catch (MockedFailedMergedRegionCreation e) {
       expectedException = true;
     }
     assertTrue(expectedException);
     // Run rollback
     assertTrue(mt.rollback(null, null));
 
     // Assert I can scan region_a and region_b.
     int rowCountOfRegionA2 = countRows(this.region_a);
     assertEquals(rowCountOfRegionA, rowCountOfRegionA2);
     int rowCountOfRegionB2 = countRows(this.region_b);
     assertEquals(rowCountOfRegionB, rowCountOfRegionB2);
 
     // Assert rollback cleaned up stuff in fs
     assertTrue(!this.fs.exists(HRegion.getRegionDir(this.testdir,
         mt.getMergedRegionInfo())));
 
     assertTrue(!this.region_a.lock.writeLock().isHeldByCurrentThread());
     assertTrue(!this.region_b.lock.writeLock().isHeldByCurrentThread());
 
     // Now retry the merge but do not throw an exception this time.
     assertTrue(mt.prepare(null));
     HRegion mergedRegion = (HRegion)mt.execute(mockServer, null);
     // Count rows. daughters are already open
     // Count rows. merged region are already open
     try {
       int mergedRegionRowCount = countRows(mergedRegion);
       assertEquals((rowCountOfRegionA + rowCountOfRegionB),
           mergedRegionRowCount);
     } finally {
       HRegion.closeHRegion(mergedRegion);
     }
     // Assert the write lock is no longer held on region_a and region_b
     assertTrue(!this.region_a.lock.writeLock().isHeldByCurrentThread());
     assertTrue(!this.region_b.lock.writeLock().isHeldByCurrentThread());
   }
 
   @Test
   public void testFailAfterPONR() throws IOException, KeeperException, InterruptedException {
     final int rowCountOfRegionA = loadRegion(this.region_a, CF, true);
     final int rowCountOfRegionB = loadRegion(this.region_b, CF, true);
     assertTrue(rowCountOfRegionA > 0 && rowCountOfRegionB > 0);
     assertEquals(rowCountOfRegionA, countRows(this.region_a));
     assertEquals(rowCountOfRegionB, countRows(this.region_b));
 
     // Start transaction.
     RegionMergeTransactionImpl mt = prepareOnGoodRegions();
     Mockito.doThrow(new MockedFailedMergedRegionOpen())
         .when(mt)
         .openMergedRegion((Server) Mockito.anyObject(),
             (RegionServerServices) Mockito.anyObject(),
             (HRegion) Mockito.anyObject());
 
     // Run the execute. Look at what it returns.
     boolean expectedException = false;
     TEST_UTIL.getConfiguration().setInt(HConstants.REGIONSERVER_PORT, 0);
     CoordinatedStateManager cp = CoordinatedStateManagerFactory.getCoordinatedStateManager(
       TEST_UTIL.getConfiguration());
     Server mockServer = new HRegionServer(TEST_UTIL.getConfiguration(), cp);
     try {
       mt.execute(mockServer, null);
     } catch (MockedFailedMergedRegionOpen e) {
       expectedException = true;
     }
     assertTrue(expectedException);
     // Run rollback returns false that we should restart.
     assertFalse(mt.rollback(null, null));
     // Make sure that merged region is still in the filesystem, that
     // they have not been removed; this is supposed to be the case if we go
     // past point of no return.
     Path tableDir = this.region_a.getRegionFileSystem().getRegionDir()
         .getParent();
     Path mergedRegionDir = new Path(tableDir, mt.getMergedRegionInfo()
         .getEncodedName());
     assertTrue(TEST_UTIL.getTestFileSystem().exists(mergedRegionDir));
   }
 
   @Test
   public void testMergedRegionBoundary() {
     TableName tableName =
         TableName.valueOf("testMergedRegionBoundary");
     byte[] a = Bytes.toBytes("a");
     byte[] b = Bytes.toBytes("b");
     byte[] z = Bytes.toBytes("z");
     HRegionInfo r1 = new HRegionInfo(tableName);
     HRegionInfo r2 = new HRegionInfo(tableName, a, z);
     HRegionInfo m = RegionMergeTransactionImpl.getMergedRegionInfo(r1, r2);
     assertTrue(Bytes.equals(m.getStartKey(), r1.getStartKey())
         && Bytes.equals(m.getEndKey(), r1.getEndKey()));
 
     r1 = new HRegionInfo(tableName, null, a);
     r2 = new HRegionInfo(tableName, a, z);
     m = RegionMergeTransactionImpl.getMergedRegionInfo(r1, r2);
     assertTrue(Bytes.equals(m.getStartKey(), r1.getStartKey())
         && Bytes.equals(m.getEndKey(), r2.getEndKey()));
 
     r1 = new HRegionInfo(tableName, null, a);
     r2 = new HRegionInfo(tableName, z, null);
     m = RegionMergeTransactionImpl.getMergedRegionInfo(r1, r2);
     assertTrue(Bytes.equals(m.getStartKey(), r1.getStartKey())
         && Bytes.equals(m.getEndKey(), r2.getEndKey()));
 
     r1 = new HRegionInfo(tableName, a, z);
     r2 = new HRegionInfo(tableName, z, null);
     m = RegionMergeTransactionImpl.getMergedRegionInfo(r1, r2);
     assertTrue(Bytes.equals(m.getStartKey(), r1.getStartKey())
       && Bytes.equals(m.getEndKey(), r2.getEndKey()));
 
     r1 = new HRegionInfo(tableName, a, b);
     r2 = new HRegionInfo(tableName, b, z);
     m = RegionMergeTransactionImpl.getMergedRegionInfo(r1, r2);
     assertTrue(Bytes.equals(m.getStartKey(), r1.getStartKey())
       && Bytes.equals(m.getEndKey(), r2.getEndKey()));
   }
 
   /**
    * Exception used in this class only.
    */
   @SuppressWarnings("serial")
   private class MockedFailedMergedRegionCreation extends IOException {
   }
 
   @SuppressWarnings("serial")
   private class MockedFailedMergedRegionOpen extends IOException {
   }
 
   private HRegion createRegion(final Path testdir, final WALFactory wals,
       final byte[] startrow, final byte[] endrow)
       throws IOException {
     // Make a region with start and end keys.
     HTableDescriptor htd = new HTableDescriptor(TableName.valueOf("table"));
     HColumnDescriptor hcd = new HColumnDescriptor(CF);
     htd.addFamily(hcd);
     HRegionInfo hri = new HRegionInfo(htd.getTableName(), startrow, endrow);
     HRegion a = HRegion.createHRegion(hri, testdir,
         TEST_UTIL.getConfiguration(), htd);
     HRegion.closeHRegion(a);
     return HRegion.openHRegion(testdir, hri, htd,
       wals.getWAL(hri.getEncodedNameAsBytes(), hri.getTable().getNamespace()),
       TEST_UTIL.getConfiguration());
   }
 
   private int countRows(final HRegion r) throws IOException {
     int rowcount = 0;
     InternalScanner scanner = r.getScanner(new Scan());
     try {
       List<Cell> kvs = new ArrayList<Cell>();
       boolean hasNext = true;
       while (hasNext) {
         hasNext = scanner.next(kvs);
         if (!kvs.isEmpty())
           rowcount++;
       }
     } finally {
       scanner.close();
     }
     return rowcount;
   }
 
   /**
    * Load region with rows from 'aaa' to 'zzz', skip the rows which are out of
    * range of the region
    * @param r Region
    * @param f Family
    * @param flush flush the cache if true
    * @return Count of rows loaded.
    * @throws IOException
    */
   private int loadRegion(final HRegion r, final byte[] f, final boolean flush)
       throws IOException {
     byte[] k = new byte[3];
     int rowCount = 0;
     for (byte b1 = 'a'; b1 <= 'z'; b1++) {
       for (byte b2 = 'a'; b2 <= 'z'; b2++) {
         for (byte b3 = 'a'; b3 <= 'z'; b3++) {
           k[0] = b1;
           k[1] = b2;
           k[2] = b3;
           if (!HRegion.rowIsInRange(r.getRegionInfo(), k)) {
             continue;
           }
           Put put = new Put(k);
           put.add(f, null, k);
           if (r.getWAL() == null)
             put.setDurability(Durability.SKIP_WAL);
           r.put(put);
           rowCount++;
         }
       }
       if (flush) {
         r.flush(true);
       }
     }
     return rowCount;
   }
 
 }