code: /*
   * 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.skywalking.oap.server.library.client.jdbc.hikaricp;
  
  import com.zaxxer.hikari.HikariConfig;
  import com.zaxxer.hikari.HikariDataSource;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.library.client.Client;
  import org.apache.skywalking.oap.server.library.client.healthcheck.DelegatedHealthChecker;
  import org.apache.skywalking.oap.server.library.client.healthcheck.HealthCheckable;
  import org.apache.skywalking.oap.server.library.util.HealthChecker;
  
  import java.sql.Connection;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.Arrays;
  import java.util.HashSet;
  import java.util.Properties;
  import java.util.Set;
  
  /**
   * JDBC Client uses HikariCP connection management lib to execute SQL.
   */
  @Slf4j
  public class JDBCClient implements Client, HealthCheckable {
      private final HikariConfig hikariConfig;
      private final DelegatedHealthChecker healthChecker;
      private HikariDataSource dataSource;
  
      public JDBCClient(Properties properties) {
          hikariConfig = new HikariConfig(properties);
          healthChecker = new DelegatedHealthChecker();
      }
  
      @Override
      public void connect() {
          dataSource = new HikariDataSource(hikariConfig);
      }
  
      @Override
      public void shutdown() {
          dataSource.close();
      }
  
      /**
       * Default getConnection is set in auto-commit.
       */
      public Connection getConnection() throws SQLException {
          return getConnection(true);
      }
  
      public Connection getConnection(boolean autoCommit) throws SQLException {
          Connection connection = dataSource.getConnection();
          connection.setAutoCommit(autoCommit);
          return connection;
      }
  
      public void execute(String sql) throws SQLException {
          if (log.isDebugEnabled()) {
              log.debug("Executing SQL: {}", sql);
          }
  
          try (final var connection = getConnection();
               final var statement = connection.createStatement()) {
              statement.execute(sql);
              statement.closeOnCompletion();
              healthChecker.health();
          } catch (SQLException e) {
              healthChecker.unHealth(e);
              throw e;
          }
      }
  
      public int executeUpdate(String sql, Object... params) throws SQLException {
          if (log.isDebugEnabled()) {
              log.debug("Executing SQL: {}", sql);
              log.debug("SQL parameters: {}", params);
          }
  
          try (final var connection = getConnection();
               final var statement = connection.prepareStatement(sql)) {
              setStatementParam(statement, params);
              int result = statement.executeUpdate();
              statement.closeOnCompletion();
              healthChecker.health();
              return result;
          } catch (SQLException e) {
              healthChecker.unHealth(e);
              throw e;
          }
      }
  
      public <T> T executeQuery(String sql, ResultHandler<T> resultHandler, Object... params) throws SQLException {
          if (log.isDebugEnabled()) {
              log.debug("Executing SQL: {}", sql);
              log.debug("SQL parameters: {}", Arrays.toString(params));
          }
          try (final var connection = getConnection();
               final var statement = connection.prepareStatement(sql)) {
              setStatementParam(statement, params);
              try (final var rs = statement.executeQuery()) {
                  healthChecker.health();
                  return resultHandler.handle(rs);
              }
          } catch (SQLException e) {
              healthChecker.unHealth(e);
              throw e;
          }
      }
  
      private void setStatementParam(PreparedStatement statement, Object[] params) throws SQLException {
          if (params != null) {
              for (int i = 0; i < params.length; i++) {
                  Object param = params[i];
                  if (param instanceof String) {
                      statement.setString(i + 1, (String) param);
                  } else if (param instanceof Integer) {
                      statement.setInt(i + 1, (int) param);
                  } else if (param instanceof Double) {
                      statement.setDouble(i + 1, (double) param);
                  } else if (param instanceof Long) {
                      statement.setLong(i + 1, (long) param);
                  } else {
                      throw new SQLException("Unsupported data type, type=" + param.getClass().getName());
                  }
              }
          }
      }
  
      @Override
      public void registerChecker(HealthChecker healthChecker) {
          this.healthChecker.register(healthChecker);
      }
  
      public boolean indexExists(final String table,
                                 final String index) throws SQLException {
          try (final var connection = getConnection();
               final var resultSet = connection.getMetaData().getIndexInfo(null, null, table, false, false)) {
              while (resultSet.next()) {
                  if (resultSet.getString("INDEX_NAME").equalsIgnoreCase(index)) {
                      return true;
                  }
              }
          }
          return false;
      }
  
      public boolean tableExists(final String table) throws SQLException {
          try (final var conn = getConnection();
               final var result = conn.getMetaData().getTables(null, null, table, null)) {
              return result.next();
          }
      }
  
      public Set<String> getTableColumns(final String table) throws SQLException {
          try (final var conn = getConnection();
               final var result = conn.getMetaData().getColumns(null, null, table, null)) {
              final var columns = new HashSet<String>();
              while (result.next()) {
                  columns.add(result.getString("COLUMN_NAME").toLowerCase());
              }
              return columns;
          }
      }
  
      @FunctionalInterface
      public interface ResultHandler<T> {
          T handle(ResultSet resultSet) throws SQLException;
      }
  }
  