code: package zemberek.corpus;
  
  import com.google.common.io.Resources;
  import java.io.IOException;
  import java.io.Reader;
  import java.nio.charset.StandardCharsets;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.sql.Clob;
  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.sql.Statement;
  import java.sql.Timestamp;
  import java.time.LocalDateTime;
  import java.util.ArrayList;
  import java.util.List;
  import org.h2.jdbcx.JdbcConnectionPool;
  import zemberek.core.logging.Log;
  import zemberek.tokenization.TurkishSentenceExtractor;
  
  public class CorpusDb {
  
    private Path dbPath;
    private JdbcConnectionPool connectionPool;
  
    public CorpusDb(Path dbRoot) throws IOException, SQLException {
      if (dbRoot.toFile().exists() && !dbRoot.toFile().isDirectory()) {
        throw new IllegalArgumentException("Database root path is not a directory :" + dbRoot);
      }
      if (!dbRoot.toFile().exists()) {
        Log.info("Creating database root folder %s", dbRoot);
        Files.createDirectories(dbRoot);
      }
      this.dbPath = dbRoot.resolve("data");
      connectionPool = JdbcConnectionPool.create(getJdbcConnectionString(), "sa", "sa");
      createTablesIfNotExist();
    }
  
    private CorpusDb(JdbcConnectionPool connectionPool) {
      this.connectionPool = connectionPool;
    }
  
    private void createTablesIfNotExist() throws IOException, SQLException {
      try {
        String connectionStr = getJdbcConnectionString() + ";IFEXISTS=TRUE";
        DriverManager.getConnection(connectionStr, "sa", "sa");
      } catch (SQLException e) {
        if (e.getErrorCode() == 90013) {
          Log.info("Creating tables for the first time.");
          generateTables();
        } else {
          throw e;
        }
      }
    }
  
    public void addAll(List<CorpusDocument> docs) {
      for (CorpusDocument doc : docs) {
        int key = saveDocument(doc);
        doc.setKey(key);
      }
    }
  
    public void generateTables() throws SQLException, IOException {
      String query = Resources.toString(
          Resources.getResource("corpus/corpus-schema.sql"), StandardCharsets.UTF_8);
      try (Connection connection = connectionPool.getConnection()) {
        Statement s = connection.createStatement();
        s.execute(query);
      }
    }
  
    private String getJdbcConnectionString() {
      return "jdbc:h2:" + dbPath.toFile().getAbsolutePath() + ";COMPRESS=TRUE";
    }
  
    public void saveSentences(int docKey, List<String> sentences) {
      try (Connection connection = connectionPool.getConnection()) {
        String sql = "INSERT INTO SENTENCE_TABLE " +
            "(DOC_KEY, CONTENT)" +
            " VALUES (?,?)";
        PreparedStatement employeeStmt = connection.prepareStatement(sql);
        for (String sentence : sentences) {
          if (sentence.length() >= 512) {
            continue;
          }
          employeeStmt.setInt(1, docKey);
          employeeStmt.setString(2, sentence);
          employeeStmt.addBatch();
        }
        employeeStmt.executeBatch();
      } catch (Exception e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  
    public List<SentenceSearchResult> search(String text) {
      try (Connection connection = connectionPool.getConnection()) {
        String sql = "SELECT T.* FROM FT_SEARCH_DATA('" + text + "', 0, 0) FT, SENTENCE_TABLE T "
            + "WHERE FT.TABLE='SENTENCE_TABLE' AND T.ID=FT.KEYS[0];";
        Statement stat = connection.createStatement();
        ResultSet set = stat.executeQuery(sql);
        List<SentenceSearchResult> result = new ArrayList<>();
        while (set.next()) {
          result.add(new SentenceSearchResult(set.getInt(1), set.getInt(2), set.getString(3)));
        }
        return result;
      } catch (Exception e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
    }
  
    int saveDocument(CorpusDocument doc) {
      try (Connection connection = connectionPool.getConnection()) {
  /*
        Clob clob = connection.createNClob();
        clob.setString(1, doc.content);
  */
  
        String sql = "INSERT INTO DOCUMENT_TABLE " +
            "(DOC_ID,SOURCE_ID,SOURCE_DATE,PROCESS_DATE)" +
            " VALUES (?,?,?,?)";
        try (PreparedStatement ps = connection
            .prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
          ps.setString(1, doc.id);
          ps.setString(2, doc.source);
          ps.setTimestamp(3, toTimeStamp(doc.sourceDate));
          ps.setTimestamp(4, toTimeStamp(doc.processDate));
          //ps.setClob(5, clob);
          ps.executeUpdate();
          ResultSet rs = ps.getGeneratedKeys();
          if (rs.next()) {
            int key = rs.getInt(1);
            doc.setKey(key);
            return key;
          } else {
            return -1;
          }
        }
      } catch (Exception e) {
        e.printStackTrace();
      }
      return -1;
    }
  
    Timestamp toTimeStamp(LocalDateTime dateTime) {
      if (dateTime == null) {
        return null;
      }
      Timestamp timestamp = Timestamp.valueOf(dateTime);
      return new Timestamp(timestamp.getTime());
    }
  
    public CorpusDocument loadDocumentByKey(int key) {
      String sql =
          "SELECT ID, DOC_ID, SOURCE_ID, SOURCE_DATE, PROCESS_DATE, CONTENT FROM DOCUMENT_TABLE " +
              "WHERE ID = " + key;
      return getDocument(sql);
    }
  
    private CorpusDocument getDocument(String sql) {
  
      CorpusDocument document = null;
      try (Connection connection = connectionPool.getConnection()) {
        Statement s = connection.createStatement();
        ResultSet rs = s.executeQuery(sql);
        while (rs.next()) {
          document = getDocumentFromResultSet(rs);
        }
      } catch (Exception e) {
        e.printStackTrace();
        throw new RuntimeException(e);
      }
      return document;
    }
  
    private CorpusDocument getDocumentFromResultSet(ResultSet rs) throws Exception {
      CorpusDocument doc;
      int key = rs.getInt(1);
      String dId = rs.getString(2);
      String sId = rs.getString(3);
      Timestamp sourceDate = rs.getTimestamp(4);
      Timestamp processDate = rs.getTimestamp(5);
  
      Clob clob = rs.getClob(6);
      String content = readClob(clob);
      clob.free();
      doc = new CorpusDocument(
          dId,
          sId,
          content,
          sourceDate == null ? null : sourceDate.toLocalDateTime(),
          processDate == null ? null : processDate.toLocalDateTime()
      );
      doc.setKey(key);
      return doc;
    }
  
    private static String readClob(Clob clob) throws SQLException, IOException {
      StringBuilder sb = new StringBuilder((int) clob.length());
      Reader r = clob.getCharacterStream();
      char[] cbuf = new char[2048];
      int n;
      while ((n = r.read(cbuf, 0, cbuf.length)) != -1) {
        sb.append(cbuf, 0, n);
      }
      return sb.toString();
    }
  
    public void addDocs(Path corpusFile) throws IOException {
      List<WebDocument> corpus = WebCorpus.loadDocuments(corpusFile);
      for (WebDocument doc : corpus) {
        CorpusDocument cd = CorpusDocument.fromWebDocument(doc);
        int key = saveDocument(cd);
        List<String> paragraphs = doc.lines;
        List<String> sentences = TurkishSentenceExtractor.DEFAULT.fromParagraphs(paragraphs);
        saveSentences(key, sentences);
      }
    }
  
  }
  