/*
 * 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.iotdb.db.integration;

import static org.junit.Assert.fail;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import org.apache.iotdb.db.conf.IoTDBDescriptor;
import org.apache.iotdb.db.utils.EnvironmentUtils;
import org.apache.iotdb.jdbc.Config;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

public class IoTDBFillIT {

  private static String[] dataSet1 = new String[]{
      "SET STORAGE GROUP TO root.ln.wf01.wt01",
      "CREATE TIMESERIES root.ln.wf01.wt01.status WITH DATATYPE=BOOLEAN, ENCODING=PLAIN",
      "CREATE TIMESERIES root.ln.wf01.wt01.temperature WITH DATATYPE=DOUBLE, ENCODING=PLAIN",
      "CREATE TIMESERIES root.ln.wf01.wt01.hardware WITH DATATYPE=INT32, ENCODING=PLAIN",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(1, 1.1, false, 11)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(2, 2.2, true, 22)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(3, 3.3, false, 33 )",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(4, 4.4, false, 44)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(5, 5.5, false, 55)",
      "flush",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(100, 100.1, false, 110)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(150, 200.2, true, 220)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(200, 300.3, false, 330 )",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(250, 400.4, false, 440)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(300, 500.5, false, 550)",
      "flush",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(10, 10.1, false, 110)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(20, 20.2, true, 220)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(30, 30.3, false, 330 )",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(40, 40.4, false, 440)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(50, 50.5, false, 550)",
      "flush",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(500, 100.1, false, 110)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(510, 200.2, true, 220)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(520, 300.3, false, 330 )",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(530, 400.4, false, 440)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(540, 500.5, false, 550)",
      "flush",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(580, 100.1, false, 110)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(590, 200.2, true, 220)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(600, 300.3, false, 330 )",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(610, 400.4, false, 440)",
      "INSERT INTO root.ln.wf01.wt01(timestamp,temperature,status, hardware) "
          + "values(620, 500.5, false, 550)",
  };

  private static String[] dataSet2 = new String[]{
      "SET STORAGE GROUP TO root.ln.wf01.wt02",
      "CREATE TIMESERIES root.ln.wf01.wt02.status WITH DATATYPE=BOOLEAN, ENCODING=PLAIN",
      "CREATE TIMESERIES root.ln.wf01.wt02.temperature WITH DATATYPE=DOUBLE, ENCODING=PLAIN",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(100, 100.1, false)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(150, 200.2, true)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(300, 500.5, false)",
      "flush",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(600, 31.1, false)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(750, 55.2, true)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(900, 1020.5, false)",
      "flush",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(1100, 98.41, false)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(1250, 220.2, true)",
      "INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) "
          + "values(1400, 31, false)",
      "flush",
  };

  private static final String TIMESTAMP_STR = "Time";
  private static final String TEMPERATURE_STR_1 = "root.ln.wf01.wt01.temperature";
  private static final String STATUS_STR_1 = "root.ln.wf01.wt01.status";
  private static final String TEMPERATURE_STR_2 = "root.ln.wf01.wt02.temperature";
  private static final String STATUS_STR_2 = "root.ln.wf01.wt02.status";
  private static final String HARDWARE_STR = "root.ln.wf01.wt01.hardware";

  boolean prevEnableUnseqCompaction;

  @Before
  public void setUp() throws Exception {
    EnvironmentUtils.closeStatMonitor();
    prevEnableUnseqCompaction = IoTDBDescriptor.getInstance().getConfig().isEnableUnseqCompaction();
    IoTDBDescriptor.getInstance().getConfig().setEnableUnseqCompaction(false);
    EnvironmentUtils.envSetUp();
    Class.forName(Config.JDBC_DRIVER_NAME);
    prepareData();
  }

  @After
  public void tearDown() throws Exception {
    EnvironmentUtils.cleanEnv();
    IoTDBDescriptor.getInstance().getConfig().setEnableUnseqCompaction(prevEnableUnseqCompaction);
  }

  @Test
  public void LinearFillCommonTest() throws SQLException {
    String[] retArray1 = new String[]{
        "3,3.3,false,33",
        "70,70.34,false,374",
        "70,70.34,false,374"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      boolean hasResultSet = statement.execute("select temperature,status, hardware from "
          + "root.ln.wf01.wt01 where time = 3 "
          + "Fill(int32[linear, 5ms, 5ms], double[linear, 5ms, 5ms], boolean[previous, 5ms])");

      Assert.assertTrue(hasResultSet);

      int cnt;
      ResultSet resultSet = statement.getResultSet();
      cnt = 0;
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 70 Fill(int32[linear, 500ms, 500ms], "
                + "double[linear, 500ms, 500ms], boolean[previous, 500ms])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 70 Fill(int32[linear], "
                + "double[linear], boolean[previous])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }

    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void LinearFillWithBeforeOrAfterValueNullTest() throws SQLException {
    String[] retArray1 = new String[]{
        "70,null,null,null",
        "80,null,null,null",
        "625,null,false,null"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {


      boolean hasResultSet = statement.execute("select temperature,status, hardware "
          + "from root.ln.wf01.wt01 where time = 70 "
          + "Fill(int32[linear, 25ms, 25ms], double[linear, 25ms, 25ms], boolean[previous, 5ms])");

      int cnt = 0;
      Assert.assertTrue(hasResultSet);
      ResultSet resultSet = statement.getResultSet();
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 80 "
                + "Fill(int32[linear, 25ms, 25ms], double[linear, 25ms, 25ms], boolean[previous, 5ms])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 625 "
                + "Fill(int32[linear, 25ms, 25ms], double[linear, 25ms, 25ms], boolean[previous, 5ms])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillTest() {
    String[] retArray1 = new String[]{
        "3,3.3,false,33",
        "70,50.5,false,550",
        "70,null,null,null"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      boolean hasResultSet = statement.execute("select temperature,status, hardware "
          + "from root.ln.wf01.wt01 where time = 3 "
          + "Fill(int32[previous, 5ms], double[previous, 5ms], boolean[previous, 5ms])");

      Assert.assertTrue(hasResultSet);
      int cnt;
      ResultSet resultSet = statement.getResultSet();
      try {
        cnt = 0;
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 70 "
                + "Fill(int32[previous, 500ms], double[previous, 500ms], boolean[previous, 500ms])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 70 "
                + "Fill(int32[previous, 15ms], double[previous, 15ms], boolean[previous, 5ms])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
        Assert.assertEquals(retArray1.length, cnt);
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void EmptyTimeRangeFillTest() throws SQLException {
    String[] retArray1 = new String[]{
        "3,3.3,false,33",
        "70,70.34,false,374"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      boolean hasResultSet = statement.execute("select temperature,status, hardware "
          + "from root.ln.wf01.wt01 where time = 3 "
          + "Fill(int32[linear], double[linear], boolean[previous])");

      Assert.assertTrue(hasResultSet);
      int cnt = 0;
      ResultSet resultSet = statement.getResultSet();
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        hasResultSet = statement.execute("select temperature,status, hardware "
                + "from root.ln.wf01.wt01 where time = 70 "
                + "Fill(int32[linear], double[linear], boolean[previous])");

        Assert.assertTrue(hasResultSet);
        resultSet = statement.getResultSet();
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_1)
                  + "," + resultSet.getString(STATUS_STR_1) + "," + resultSet.getString(HARDWARE_STR);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillWithOnlySeqFileTest() throws SQLException {
    String[] retArray = new String[]{
        "1050,1020.5,false",
        "800,55.2,true"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      ResultSet resultSet = statement.executeQuery("select temperature,status "
          + "from root.ln.wf01.wt02 where time = 1050 Fill(double[previous])");

      int cnt = 0;
      try {
        while (resultSet.next()) {
          String ans =
                  resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                          + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }

        resultSet = statement.executeQuery("select temperature,status "
                + "from root.ln.wf01.wt02 where time = 800 Fill(double[previous])");

        while (resultSet.next()) {
          String ans =
                  resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                          + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillWithOnlyUnseqFileOverlappedTest() throws SQLException {
    String[] retArray = new String[]{
        "58,82.1,true",
        "40,121.22,true",
        "80,32.2,false"
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(50, 82.1, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(35, 121.22, true)");
      statement.execute("flush");

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(25, 102.15, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(78, 32.2, false)");
      statement.execute("flush");

      int cnt = 0;
      ResultSet resultSet = statement.executeQuery("select temperature,status "
              + "from root.ln.wf01.wt02 where time = 58 Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                  + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }

        resultSet = statement.executeQuery("select temperature,status "
                + "from root.ln.wf01.wt02 where time = 40 Fill(double[previous])");
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                  + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }

        resultSet = statement.executeQuery("select temperature,status "
                + "from root.ln.wf01.wt02 where time = 80 Fill(double[previous])");
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                  + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillMultiUnseqFileWithSameLastTest() throws SQLException {
    String[] retArray = new String[]{
        "59,82.1,true",
        "52,32.2,false",
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(50, 82.1, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(35, 121.22, true)");
      statement.execute("flush");

      int cnt = 0;
      ResultSet resultSet = statement.executeQuery("select temperature,status "
          + "from root.ln.wf01.wt02 where time = 59 Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                  + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }

        statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(25, 102.15, true)");
        statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(50, 32.2, false)");
        statement.execute("flush");

        resultSet = statement.executeQuery("select temperature,status "
                + "from root.ln.wf01.wt02 where time = 52 Fill(double[previous])");
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + "," + resultSet.getString(TEMPERATURE_STR_2)
                  + "," + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillSeqFileFilterOverlappedFilesTest() throws SQLException {
    String[] retArray1 = new String[]{
        "886,55.2,true",
        "730,121.22,true",
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      int cnt = 0;
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(950, 82.1, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(650, 121.22, true)");
      statement.execute("flush");

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(740, 33.1, false)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(420, 125.1, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(890, 22.82, false)");
      statement.execute("flush");

      ResultSet resultSet = statement.executeQuery(
              "select temperature,status from root.ln.wf01.wt02 where time = 886 "
                  + "Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + ","
                  + resultSet.getString(TEMPERATURE_STR_2) + ","
                  + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        resultSet = statement.executeQuery(
                "select temperature,status from root.ln.wf01.wt02 where time = 730 "
                    + "Fill(double[previous])");

        while (resultSet.next()) {
          String ans =
              resultSet.getString(TIMESTAMP_STR) + ","
                  + resultSet.getString(TEMPERATURE_STR_2) + ","
                  + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillUnseqFileFilterOverlappedFilesTest() throws SQLException {
    String[] retArray1 = new String[]{
        "990,121.22,true",
        "925,33.1,false",
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      int cnt = 0;
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(1030, 82.1, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(940, 121.22, true)");
      statement.execute("flush");

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(740, 62.1, false)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,status) values(980, true)");
      statement.execute("flush");

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(910, 33.1, false)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(620, 125.1, true)");
      statement.execute("flush");

      ResultSet resultSet = statement.executeQuery(
            "select temperature,status from root.ln.wf01.wt02 where time = 990 "
                + "Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + ","
              + resultSet.getString(TEMPERATURE_STR_2) + ","
              + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }

        resultSet = statement.executeQuery(
            "select temperature,status from root.ln.wf01.wt02 where time = 925 "
                + "Fill(double[previous])");

        while (resultSet.next()) {
          String ans =
              resultSet.getString(TIMESTAMP_STR) + ","
                  + resultSet.getString(TEMPERATURE_STR_2) + ","
                  + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }
    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillWithNullUnseqFilesTest() throws SQLException {
    String[] retArray1 = new String[]{
        "990,1020.5,true",
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      int cnt = 0;
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp, temperature, status) values(1030, 21.6, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,status) values(940, true)");
      statement.execute("flush");

      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,status) values(740, false)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,status) values(980, true)");
      statement.execute("flush");

      ResultSet resultSet = statement.executeQuery(
            "select temperature,status from root.ln.wf01.wt02 where time = 990 "
                + "Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + ","
              + resultSet.getString(TEMPERATURE_STR_2) + ","
              + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }

    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  @Test
  public void PreviousFillWithDeletionTest() throws SQLException {
    String[] retArray1 = new String[]{
        "1080,21.6,true",
    };
    try (Connection connection = DriverManager.
        getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
        Statement statement = connection.createStatement()) {

      int cnt = 0;
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp, temperature, status) values(1030, 21.6, true)");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp, temperature, status) values(940, 188.2, false)");


      statement.execute("DELETE FROM root.ln.wf01.wt02.temperature WHERE time < 1000");
      statement.execute("flush");
      statement.execute("INSERT INTO root.ln.wf01.wt02(timestamp,temperature,status) values(980, 47.22, true)");
      statement.execute("flush");

      ResultSet resultSet = statement.executeQuery(
            "select temperature,status from root.ln.wf01.wt02 where time = 1080 "
                + "Fill(double[previous])");
      try {
        while (resultSet.next()) {
          String ans = resultSet.getString(TIMESTAMP_STR) + ","
              + resultSet.getString(TEMPERATURE_STR_2) + ","
              + resultSet.getString(STATUS_STR_2);
          Assert.assertEquals(retArray1[cnt], ans);
          cnt++;
        }
      } finally {
        resultSet.close();
      }

    } catch (Exception e) {
      e.printStackTrace();
      fail(e.getMessage());
    }
  }

  private void prepareData() {
    try (Connection connection = DriverManager
        .getConnection(Config.IOTDB_URL_PREFIX + "127.0.0.1:6667/", "root",
            "root");
        Statement statement = connection.createStatement()) {


      for (String sql : dataSet1) {
        statement.execute(sql);
      }
      for (String sql : dataSet2) {
        statement.execute(sql);
      }

    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}
