/**
    * 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.client;
  
  import static org.junit.Assert.assertArrayEquals;
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNull;
  import static org.junit.Assert.assertNotNull;
  
  import java.io.IOException;
  
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.regionserver.HRegionServer;
  import org.apache.hadoop.hbase.testclassification.ClientTests;
  import org.apache.hadoop.hbase.testclassification.LargeTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.JVMClusterUtil;
  import org.junit.AfterClass;
  import org.junit.Before;
  import org.junit.BeforeClass;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.junit.rules.TestName;
  
  @Category({ LargeTests.class, ClientTests.class })
  public class TestMvccConsistentScanner {
  
    private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();
  
    private static Connection CONN;
  
    private static final byte[] CF = Bytes.toBytes("cf");
  
    private static final byte[] CQ1 = Bytes.toBytes("cq1");
  
    private static final byte[] CQ2 = Bytes.toBytes("cq2");
  
    private static final byte[] CQ3 = Bytes.toBytes("cq3");
    @Rule
    public TestName testName = new TestName();
  
    private TableName tableName;
  
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
      UTIL.startMiniCluster(2);
      CONN = ConnectionFactory.createConnection(UTIL.getConfiguration());
    }
  
    @AfterClass
    public static void tearDownAfterClass() throws Exception {
      CONN.close();
      UTIL.shutdownMiniCluster();
    }
  
    @Before
    public void setUp() throws IOException, InterruptedException {
      tableName = TableName.valueOf(testName.getMethodName().replaceAll("[^0-9a-zA-Z]", "_"));
      UTIL.createTable(tableName, CF);
      UTIL.waitTableAvailable(tableName);
    }
  
    private void put(byte[] row, byte[] cq, byte[] value) throws IOException {
      try (Table table = CONN.getTable(tableName)) {
        table.put(new Put(row).addColumn(CF, cq, value));
      }
    }
  
    private void move() throws IOException, InterruptedException {
      HRegionInfo region = UTIL.getHBaseCluster().getRegions(tableName).get(0).getRegionInfo();
      HRegionServer rs = null;
      for (JVMClusterUtil.RegionServerThread thread : UTIL.getHBaseCluster()
          .getRegionServerThreads()) {
        if (!thread.getRegionServer().getOnlineTables().contains(tableName)) {
          rs = thread.getRegionServer();
          break;
        }
      }
      assertNotNull(rs);
      UTIL.getHBaseAdmin().move(region.getEncodedNameAsBytes(),
        Bytes.toBytes(rs.getServerName().getServerName()));
     while (UTIL.getRSForFirstRegionInTable(tableName) != rs) {
       Thread.sleep(100);
     }
   }
 
   @Test
   public void testRowAtomic() throws IOException, InterruptedException {
     byte[] row = Bytes.toBytes("row");
     put(row, CQ1, Bytes.toBytes(1));
     put(row, CQ2, Bytes.toBytes(2));
     try (Table table = CONN.getTable(tableName);
         ResultScanner scanner = table.getScanner(new Scan().setBatch(1).setCaching(1))) {
       Result result = scanner.next();
       assertEquals(1, result.rawCells().length);
       assertEquals(1, Bytes.toInt(result.getValue(CF, CQ1)));
       move();
       put(row, CQ3, Bytes.toBytes(3));
       result = scanner.next();
       assertEquals(1, result.rawCells().length);
       assertEquals(2, Bytes.toInt(result.getValue(CF, CQ2)));
       assertNull(scanner.next());
     }
   }
 
   @Test
   public void testCrossRowAtomicInRegion() throws IOException, InterruptedException {
     put(Bytes.toBytes("row1"), CQ1, Bytes.toBytes(1));
     put(Bytes.toBytes("row2"), CQ1, Bytes.toBytes(2));
     try (Table table = CONN.getTable(tableName);
         ResultScanner scanner = table.getScanner(new Scan().setCaching(1))) {
       Result result = scanner.next();
       assertArrayEquals(Bytes.toBytes("row1"), result.getRow());
       assertEquals(1, Bytes.toInt(result.getValue(CF, CQ1)));
       move();
       put(Bytes.toBytes("row3"), CQ1, Bytes.toBytes(3));
       result = scanner.next();
       assertArrayEquals(Bytes.toBytes("row2"), result.getRow());
       assertEquals(2, Bytes.toInt(result.getValue(CF, CQ1)));
       assertNull(scanner.next());
     }
   }
 }