/**
    * 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.
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  package org.apache.hadoop.hbase.mapreduce;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.CategoryBasedTimeout;
  import org.apache.hadoop.hbase.Cell;
  import org.apache.hadoop.hbase.CellScanner;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.io.HFileLink;
  import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
  import org.apache.hadoop.hbase.master.snapshot.SnapshotManager;
  import org.apache.hadoop.hbase.regionserver.StoreFileInfo;
  import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.HFileArchiveUtil;
  import org.junit.Assert;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.TestRule;
  
  import static org.junit.Assert.assertFalse;
  
  import java.io.IOException;
  import java.util.Arrays;
  
  public abstract class TableSnapshotInputFormatTestBase {
    private static final Log LOG = LogFactory.getLog(TableSnapshotInputFormatTestBase.class);
    @Rule public final TestRule timeout = CategoryBasedTimeout.builder().
        withTimeout(this.getClass()).withLookingForStuckThread(true).build();
    protected final HBaseTestingUtility UTIL = new HBaseTestingUtility();
    protected static final int NUM_REGION_SERVERS = 2;
    protected static final byte[][] FAMILIES = {Bytes.toBytes("f1"), Bytes.toBytes("f2")};
  
    protected FileSystem fs;
    protected Path rootDir;
  
    public void setupCluster() throws Exception {
      setupConf(UTIL.getConfiguration());
      UTIL.setJobWithoutMRCluster();
      UTIL.startMiniCluster(NUM_REGION_SERVERS, true);
      rootDir = UTIL.getHBaseCluster().getMaster().getMasterFileSystem().getRootDir();
      fs = rootDir.getFileSystem(UTIL.getConfiguration());
    }
  
    public void tearDownCluster() throws Exception {
      UTIL.shutdownMiniCluster();
    }
  
    private static void setupConf(Configuration conf) {
      // Enable snapshot
      conf.setBoolean(SnapshotManager.HBASE_SNAPSHOT_ENABLED, true);
    }
  
    protected abstract void testWithMockedMapReduce(HBaseTestingUtility util, String snapshotName,
      int numRegions, int numSplitsPerRegion, int expectedNumSplits) throws Exception;
  
    protected abstract void testWithMapReduceImpl(HBaseTestingUtility util, TableName tableName,
      String snapshotName, Path tableDir, int numRegions, int numSplitsPerRegion, int expectedNumSplits,
      boolean shutdownCluster) throws Exception;
  
    protected abstract byte[] getStartRow();
  
    protected abstract byte[] getEndRow();
  
    @Test
    public void testWithMockedMapReduceSingleRegion() throws Exception {
      testWithMockedMapReduce(UTIL, "testWithMockedMapReduceSingleRegion", 1, 1, 1);
    }
  
    @Test
    public void testWithMockedMapReduceMultiRegion() throws Exception {
      testWithMockedMapReduce(UTIL, "testWithMockedMapReduceMultiRegion", 10, 1, 8);
   }
 
   @Test
   public void testWithMapReduceSingleRegion() throws Exception {
     testWithMapReduce(UTIL, "testWithMapReduceSingleRegion", 1, 1, 1, false);
   }
 
   @Test
   public void testWithMapReduceMultiRegion() throws Exception {
     testWithMapReduce(UTIL, "testWithMapReduceMultiRegion", 10, 1, 8, false);
   }
 
   @Test
   public void testWithMapReduceMultipleMappersPerRegion() throws Exception {
     testWithMapReduce(UTIL, "testWithMapReduceMultiRegion", 10, 5, 50, false);
   }
 
   @Test
   // run the MR job while HBase is offline
   public void testWithMapReduceAndOfflineHBaseMultiRegion() throws Exception {
     testWithMapReduce(UTIL, "testWithMapReduceAndOfflineHBaseMultiRegion", 10, 1, 8, true);
   }
 
   // Test that snapshot restore does not create back references in the HBase root dir.
   @Test
   public void testRestoreSnapshotDoesNotCreateBackRefLinks() throws Exception {
     setupCluster();
     TableName tableName = TableName.valueOf("testRestoreSnapshotDoesNotCreateBackRefLinks");
     String snapshotName = "foo";
 
     try {
       createTableAndSnapshot(UTIL, tableName, snapshotName, getStartRow(), getEndRow(), 1);
 
       Path tmpTableDir = UTIL.getRandomDir();
 
       testRestoreSnapshotDoesNotCreateBackRefLinksInit(tableName, snapshotName,tmpTableDir);
 
       Path rootDir = FSUtils.getRootDir(UTIL.getConfiguration());
       for (Path regionDir : FSUtils.getRegionDirs(fs, FSUtils.getTableDir(rootDir, tableName))) {
         for (Path storeDir : FSUtils.getFamilyDirs(fs, regionDir)) {
           for (FileStatus status : fs.listStatus(storeDir)) {
             System.out.println(status.getPath());
             if (StoreFileInfo.isValid(status)) {
               Path archiveStoreDir = HFileArchiveUtil.getStoreArchivePath(UTIL.getConfiguration(),
                 tableName, regionDir.getName(), storeDir.getName());
 
               Path path = HFileLink.getBackReferencesDir(storeDir, status.getPath().getName());
               // assert back references directory is empty
               assertFalse("There is a back reference in " + path, fs.exists(path));
 
               path = HFileLink.getBackReferencesDir(archiveStoreDir, status.getPath().getName());
               // assert back references directory is empty
               assertFalse("There is a back reference in " + path, fs.exists(path));
             }
           }
         }
       }
     } finally {
       UTIL.getHBaseAdmin().deleteSnapshot(snapshotName);
       UTIL.deleteTable(tableName);
       tearDownCluster();
     }
   }
 
   public abstract void testRestoreSnapshotDoesNotCreateBackRefLinksInit(TableName tableName,
       String snapshotName, Path tmpTableDir) throws Exception;
 
   protected void testWithMapReduce(HBaseTestingUtility util, String snapshotName,
       int numRegions, int numSplitsPerRegion, int expectedNumSplits, boolean shutdownCluster) throws Exception {
     setupCluster();
     try {
       Path tableDir = util.getRandomDir();
       TableName tableName = TableName.valueOf("testWithMapReduce");
       testWithMapReduceImpl(util, tableName, snapshotName, tableDir, numRegions,
         numSplitsPerRegion, expectedNumSplits, shutdownCluster);
     } finally {
       tearDownCluster();
     }
   }
 
   protected static void verifyRowFromMap(ImmutableBytesWritable key, Result result)
     throws IOException {
     byte[] row = key.get();
     CellScanner scanner = result.cellScanner();
     while (scanner.advance()) {
       Cell cell = scanner.current();
 
       //assert that all Cells in the Result have the same key
       Assert.assertEquals(0, Bytes.compareTo(row, 0, row.length,
         cell.getRowArray(), cell.getRowOffset(), cell.getRowLength()));
     }
 
     for (int j = 0; j < FAMILIES.length; j++) {
       byte[] actual = result.getValue(FAMILIES[j], FAMILIES[j]);
       Assert.assertArrayEquals("Row in snapshot does not match, expected:" + Bytes.toString(row)
         + " ,actual:" + Bytes.toString(actual), row, actual);
     }
   }
 
   protected static void createTableAndSnapshot(HBaseTestingUtility util, TableName tableName,
     String snapshotName, byte[] startRow, byte[] endRow, int numRegions)
     throws Exception {
     try {
       LOG.debug("Ensuring table doesn't exist.");
       util.deleteTable(tableName);
     } catch(Exception ex) {
       // ignore
     }
 
     LOG.info("creating table '" + tableName + "'");
     if (numRegions > 1) {
       util.createTable(tableName, FAMILIES, 1, startRow, endRow, numRegions);
     } else {
       util.createTable(tableName, FAMILIES);
     }
     Admin admin = util.getHBaseAdmin();
 
     LOG.info("put some stuff in the table");
     HTable table = new HTable(util.getConfiguration(), tableName);
     util.loadTable(table, FAMILIES);
 
     Path rootDir = FSUtils.getRootDir(util.getConfiguration());
     FileSystem fs = rootDir.getFileSystem(util.getConfiguration());
 
     LOG.info("snapshot");
     SnapshotTestingUtils.createSnapshotAndValidate(admin, tableName,
       Arrays.asList(FAMILIES), null, snapshotName, rootDir, fs, true);
 
     LOG.info("load different values");
     byte[] value = Bytes.toBytes("after_snapshot_value");
     util.loadTable(table, FAMILIES, value);
 
     LOG.info("cause flush to create new files in the region");
     admin.flush(tableName);
     table.close();
   }
 
 }