/*
 * 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.calcite.avatica.jdbc;

import org.apache.calcite.avatica.AvaticaParameter;
import org.apache.calcite.avatica.AvaticaPreparedStatement;
import org.apache.calcite.avatica.AvaticaUtils;
import org.apache.calcite.avatica.ColumnMetaData;
import org.apache.calcite.avatica.ConnectionPropertiesImpl;
import org.apache.calcite.avatica.Meta;
import org.apache.calcite.avatica.MetaImpl;
import org.apache.calcite.avatica.MissingResultsException;
import org.apache.calcite.avatica.NoSuchConnectionException;
import org.apache.calcite.avatica.NoSuchStatementException;
import org.apache.calcite.avatica.QueryState;
import org.apache.calcite.avatica.SqlType;
import org.apache.calcite.avatica.metrics.Gauge;
import org.apache.calcite.avatica.metrics.MetricsSystem;
import org.apache.calcite.avatica.metrics.noop.NoopMetricsSystem;
import org.apache.calcite.avatica.proto.Common;
import org.apache.calcite.avatica.proto.Requests;
import org.apache.calcite.avatica.remote.ProtobufMeta;
import org.apache.calcite.avatica.remote.TypedValue;
import org.apache.calcite.avatica.util.Unsafe;

import com.google.common.base.Optional;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static org.apache.calcite.avatica.remote.MetricsHelper.concat;

import java.lang.reflect.InvocationTargetException;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Properties;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

/** Implementation of {@link Meta} upon an existing JDBC data source. */
public class JdbcMeta implements ProtobufMeta {
  private static final Logger LOG = LoggerFactory.getLogger(JdbcMeta.class);

  private static final String CONN_CACHE_KEY_BASE = "avatica.connectioncache";

  private static final String STMT_CACHE_KEY_BASE = "avatica.statementcache";

  /** Special value for {@code Statement#getLargeMaxRows()} that means fetch
   * an unlimited number of rows in a single batch.
   *
   * <p>Any other negative value will return an unlimited number of rows but
   * will do it in the default batch size, namely 100. */
  public static final int UNLIMITED_COUNT = -2;

  // End of constants, start of member variables

  final Calendar calendar = Unsafe.localCalendar();

  /** Generates ids for statements. The ids are unique across all connections
   * created by this JdbcMeta. */
  private final AtomicInteger statementIdGenerator = new AtomicInteger();

  private final String url;
  private final Properties info;
  private final Cache<String, Connection> connectionCache;
  private final Cache<Integer, StatementInfo> statementCache;
  private final MetricsSystem metrics;

  /**
   * Creates a JdbcMeta.
   *
   * @param url a database url of the form
   *  <code>jdbc:<em>subprotocol</em>:<em>subname</em></code>
   */
  public JdbcMeta(String url) throws SQLException {
    this(url, new Properties());
  }

  /**
   * Creates a JdbcMeta.
   *
   * @param url a database url of the form
   * <code>jdbc:<em>subprotocol</em>:<em>subname</em></code>
   * @param user the database user on whose behalf the connection is being
   *   made
   * @param password the user's password
   */
  public JdbcMeta(final String url, final String user, final String password)
      throws SQLException {
    this(url, new Properties() {
      {
        put("user", user);
        put("password", password);
      }
    });
  }

  public JdbcMeta(String url, Properties info) throws SQLException {
    this(url, info, NoopMetricsSystem.getInstance());
  }

  /**
   * Creates a JdbcMeta.
   *
   * @param url a database url of the form
   * <code> jdbc:<em>subprotocol</em>:<em>subname</em></code>
   * @param info a list of arbitrary string tag/value pairs as
   * connection arguments; normally at least a "user" and
   * "password" property should be included
   */
  public JdbcMeta(String url, Properties info, MetricsSystem metrics)
      throws SQLException {
    this.url = url;
    this.info = info;
    this.metrics = Objects.requireNonNull(metrics);

    int concurrencyLevel = Integer.parseInt(
        info.getProperty(ConnectionCacheSettings.CONCURRENCY_LEVEL.key(),
            ConnectionCacheSettings.CONCURRENCY_LEVEL.defaultValue()));
    int initialCapacity = Integer.parseInt(
        info.getProperty(ConnectionCacheSettings.INITIAL_CAPACITY.key(),
            ConnectionCacheSettings.INITIAL_CAPACITY.defaultValue()));
    long maxCapacity = Long.parseLong(
        info.getProperty(ConnectionCacheSettings.MAX_CAPACITY.key(),
            ConnectionCacheSettings.MAX_CAPACITY.defaultValue()));
    long connectionExpiryDuration = Long.parseLong(
        info.getProperty(ConnectionCacheSettings.EXPIRY_DURATION.key(),
            ConnectionCacheSettings.EXPIRY_DURATION.defaultValue()));
    TimeUnit connectionExpiryUnit = TimeUnit.valueOf(
        info.getProperty(ConnectionCacheSettings.EXPIRY_UNIT.key(),
            ConnectionCacheSettings.EXPIRY_UNIT.defaultValue()));
    this.connectionCache = CacheBuilder.newBuilder()
        .concurrencyLevel(concurrencyLevel)
        .initialCapacity(initialCapacity)
        .maximumSize(maxCapacity)
        .expireAfterAccess(connectionExpiryDuration, connectionExpiryUnit)
        .removalListener(new ConnectionExpiryHandler())
        .build();
    LOG.debug("instantiated connection cache: {}", connectionCache.stats());

    concurrencyLevel = Integer.parseInt(
        info.getProperty(StatementCacheSettings.CONCURRENCY_LEVEL.key(),
            StatementCacheSettings.CONCURRENCY_LEVEL.defaultValue()));
    initialCapacity = Integer.parseInt(
        info.getProperty(StatementCacheSettings.INITIAL_CAPACITY.key(),
            StatementCacheSettings.INITIAL_CAPACITY.defaultValue()));
    maxCapacity = Long.parseLong(
        info.getProperty(StatementCacheSettings.MAX_CAPACITY.key(),
            StatementCacheSettings.MAX_CAPACITY.defaultValue()));
    connectionExpiryDuration = Long.parseLong(
        info.getProperty(StatementCacheSettings.EXPIRY_DURATION.key(),
            StatementCacheSettings.EXPIRY_DURATION.defaultValue()));
    connectionExpiryUnit = TimeUnit.valueOf(
        info.getProperty(StatementCacheSettings.EXPIRY_UNIT.key(),
            StatementCacheSettings.EXPIRY_UNIT.defaultValue()));
    this.statementCache = CacheBuilder.newBuilder()
        .concurrencyLevel(concurrencyLevel)
        .initialCapacity(initialCapacity)
        .maximumSize(maxCapacity)
        .expireAfterAccess(connectionExpiryDuration, connectionExpiryUnit)
        .removalListener(new StatementExpiryHandler())
        .build();

    LOG.debug("instantiated statement cache: {}", statementCache.stats());

    // Register some metrics
    this.metrics.register(concat(JdbcMeta.class, "ConnectionCacheSize"), new Gauge<Long>() {
      @Override public Long getValue() {
        return connectionCache.size();
      }
    });

    this.metrics.register(concat(JdbcMeta.class, "StatementCacheSize"), new Gauge<Long>() {
      @Override public Long getValue() {
        return statementCache.size();
      }
    });
  }

  // For testing purposes
  protected AtomicInteger getStatementIdGenerator() {
    return statementIdGenerator;
  }

  // For testing purposes
  protected Cache<String, Connection> getConnectionCache() {
    return connectionCache;
  }

  // For testing purposes
  protected Cache<Integer, StatementInfo> getStatementCache() {
    return statementCache;
  }

  /**
   * Converts from JDBC metadata to Avatica columns.
   */
  protected static List<ColumnMetaData>
  columns(ResultSetMetaData metaData) throws SQLException {
    if (metaData == null) {
      return Collections.emptyList();
    }
    final List<ColumnMetaData> columns = new ArrayList<>();
    for (int i = 1; i <= metaData.getColumnCount(); i++) {
      final SqlType sqlType = SqlType.valueOf(metaData.getColumnType(i));
      final ColumnMetaData.Rep rep = ColumnMetaData.Rep.of(sqlType.internal);
      final ColumnMetaData.AvaticaType t;
      if (sqlType == SqlType.ARRAY || sqlType == SqlType.STRUCT || sqlType == SqlType.MULTISET) {
        ColumnMetaData.AvaticaType arrayValueType = ColumnMetaData.scalar(Types.JAVA_OBJECT,
            metaData.getColumnTypeName(i), ColumnMetaData.Rep.OBJECT);
        t = ColumnMetaData.array(arrayValueType, metaData.getColumnTypeName(i), rep);
      } else {
        t = ColumnMetaData.scalar(metaData.getColumnType(i), metaData.getColumnTypeName(i), rep);
      }
      ColumnMetaData md =
          new ColumnMetaData(i - 1, metaData.isAutoIncrement(i),
              metaData.isCaseSensitive(i), metaData.isSearchable(i),
              metaData.isCurrency(i), metaData.isNullable(i),
              metaData.isSigned(i), metaData.getColumnDisplaySize(i),
              metaData.getColumnLabel(i), metaData.getColumnName(i),
              metaData.getSchemaName(i), metaData.getPrecision(i),
              metaData.getScale(i), metaData.getTableName(i),
              metaData.getCatalogName(i), t, metaData.isReadOnly(i),
              metaData.isWritable(i), metaData.isDefinitelyWritable(i),
              metaData.getColumnClassName(i));
      columns.add(md);
    }
    return columns;
  }

  /**
   * Converts from JDBC metadata to Avatica parameters
   */
  protected static List<AvaticaParameter> parameters(ParameterMetaData metaData)
      throws SQLException {
    if (metaData == null) {
      return Collections.emptyList();
    }
    final List<AvaticaParameter> params = new ArrayList<>();
    for (int i = 1; i <= metaData.getParameterCount(); i++) {
      params.add(
          new AvaticaParameter(metaData.isSigned(i), metaData.getPrecision(i),
              metaData.getScale(i), metaData.getParameterType(i),
              metaData.getParameterTypeName(i),
              metaData.getParameterClassName(i), "?" + i));
    }
    return params;
  }

  protected static Signature signature(ResultSetMetaData metaData,
      ParameterMetaData parameterMetaData, String sql,
      Meta.StatementType statementType) throws  SQLException {
    final CursorFactory cf = CursorFactory.LIST;  // because JdbcResultSet#frame
    return new Signature(columns(metaData), sql, parameters(parameterMetaData),
        null, cf, statementType);
  }

  protected static Signature signature(ResultSetMetaData metaData)
      throws SQLException {
    return signature(metaData, null, null, null);
  }

  public Map<DatabaseProperty, Object> getDatabaseProperties(ConnectionHandle ch) {
    try {
      final Map<DatabaseProperty, Object> map = new HashMap<>();
      final Connection conn = getConnection(ch.id);
      final DatabaseMetaData metaData = conn.getMetaData();
      for (DatabaseProperty p : DatabaseProperty.values()) {
        addProperty(map, metaData, p);
      }
      return map;
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  private static Object addProperty(Map<DatabaseProperty, Object> map,
      DatabaseMetaData metaData, DatabaseProperty p) throws SQLException {
    Object propertyValue;
    if (p.isJdbc) {
      try {
        propertyValue = p.method.invoke(metaData);
      } catch (IllegalAccessException | InvocationTargetException e) {
        throw new RuntimeException(e);
      }
    } else {
      propertyValue = p.defaultValue;
    }

    return map.put(p, propertyValue);
  }

  public MetaResultSet getTables(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat tableNamePattern, List<String> typeList) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getTables(catalog, schemaPattern.s,
              tableNamePattern.s, toArray(typeList));
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  /**
    * Registers a StatementInfo for the given ResultSet, returning the id under
    * which it is registered. This should be used for metadata ResultSets, which
    * have an implicit statement created.
    */
  private int registerMetaStatement(ResultSet rs) throws SQLException {
    final int id = statementIdGenerator.getAndIncrement();
    StatementInfo statementInfo = new StatementInfo(rs.getStatement());
    statementInfo.setResultSet(rs);
    statementCache.put(id, statementInfo);
    return id;
  }

  public MetaResultSet getColumns(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat tableNamePattern, Pat columnNamePattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getColumns(catalog, schemaPattern.s,
              tableNamePattern.s, columnNamePattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getSchemas(ConnectionHandle ch, String catalog, Pat schemaPattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getSchemas(catalog, schemaPattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getCatalogs(ConnectionHandle ch) {
    try {
      final ResultSet rs = getConnection(ch.id).getMetaData().getCatalogs();
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getTableTypes(ConnectionHandle ch) {
    try {
      final ResultSet rs = getConnection(ch.id).getMetaData().getTableTypes();
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getProcedures(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat procedureNamePattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getProcedures(catalog, schemaPattern.s,
              procedureNamePattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getProcedureColumns(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat procedureNamePattern, Pat columnNamePattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getProcedureColumns(catalog,
              schemaPattern.s, procedureNamePattern.s, columnNamePattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getColumnPrivileges(ConnectionHandle ch, String catalog, String schema,
      String table, Pat columnNamePattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getColumnPrivileges(catalog, schema,
              table, columnNamePattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getTablePrivileges(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat tableNamePattern) {
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getTablePrivileges(catalog,
              schemaPattern.s, tableNamePattern.s);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getBestRowIdentifier(ConnectionHandle ch, String catalog, String schema,
      String table, int scope, boolean nullable) {
    LOG.trace("getBestRowIdentifier catalog:{} schema:{} table:{} scope:{} nullable:{}", catalog,
        schema, table, scope, nullable);
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getBestRowIdentifier(catalog, schema,
              table, scope, nullable);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getVersionColumns(ConnectionHandle ch, String catalog, String schema,
      String table) {
    LOG.trace("getVersionColumns catalog:{} schema:{} table:{}", catalog, schema, table);
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getVersionColumns(catalog, schema, table);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getPrimaryKeys(ConnectionHandle ch, String catalog, String schema,
      String table) {
    LOG.trace("getPrimaryKeys catalog:{} schema:{} table:{}", catalog, schema, table);
    try {
      final ResultSet rs =
          getConnection(ch.id).getMetaData().getPrimaryKeys(catalog, schema, table);
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getImportedKeys(ConnectionHandle ch, String catalog, String schema,
      String table) {
    return null;
  }

  public MetaResultSet getExportedKeys(ConnectionHandle ch, String catalog, String schema,
      String table) {
    return null;
  }

  public MetaResultSet getCrossReference(ConnectionHandle ch, String parentCatalog,
      String parentSchema, String parentTable, String foreignCatalog,
      String foreignSchema, String foreignTable) {
    return null;
  }

  public MetaResultSet getTypeInfo(ConnectionHandle ch) {
    try {
      final ResultSet rs = getConnection(ch.id).getMetaData().getTypeInfo();
      int stmtId = registerMetaStatement(rs);
      return JdbcResultSet.create(ch.id, stmtId, rs);
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  public MetaResultSet getIndexInfo(ConnectionHandle ch, String catalog, String schema,
      String table, boolean unique, boolean approximate) {
    return null;
  }

  public MetaResultSet getUDTs(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat typeNamePattern, int[] types) {
    return null;
  }

  public MetaResultSet getSuperTypes(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat typeNamePattern) {
    return null;
  }

  public MetaResultSet getSuperTables(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat tableNamePattern) {
    return null;
  }

  public MetaResultSet getAttributes(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat typeNamePattern, Pat attributeNamePattern) {
    return null;
  }

  public MetaResultSet getClientInfoProperties(ConnectionHandle ch) {
    return null;
  }

  public MetaResultSet getFunctions(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat functionNamePattern) {
    return null;
  }

  public MetaResultSet getFunctionColumns(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat functionNamePattern, Pat columnNamePattern) {
    return null;
  }

  public MetaResultSet getPseudoColumns(ConnectionHandle ch, String catalog, Pat schemaPattern,
      Pat tableNamePattern, Pat columnNamePattern) {
    return null;
  }

  public Iterable<Object> createIterable(StatementHandle handle, QueryState state,
      Signature signature, List<TypedValue> parameterValues, Frame firstFrame) {
    return null;
  }

  protected Connection getConnection(String id) throws SQLException {
    if (id == null) {
      throw new NullPointerException("Connection id is null.");
    }
    Connection conn = connectionCache.getIfPresent(id);
    if (conn == null) {
      throw new NoSuchConnectionException("Connection not found: invalid id, closed, or expired: "
          + id);
    }
    return conn;
  }

  public StatementHandle createStatement(ConnectionHandle ch) {
    try {
      final Connection conn = getConnection(ch.id);
      final Statement statement = conn.createStatement();
      final int id = statementIdGenerator.getAndIncrement();
      statementCache.put(id, new StatementInfo(statement));
      StatementHandle h = new StatementHandle(ch.id, id, null);
      LOG.trace("created statement {}", h);
      return h;
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public void closeStatement(StatementHandle h) {
    StatementInfo info = statementCache.getIfPresent(h.id);
    if (info == null || info.statement == null) {
      LOG.debug("client requested close unknown statement {}", h);
      return;
    }
    LOG.trace("closing statement {}", h);
    try {
      ResultSet results = info.getResultSet();
      if (info.isResultSetInitialized() && null != results) {
        results.close();
      }
      info.statement.close();
    } catch (SQLException e) {
      throw propagate(e);
    } finally {
      statementCache.invalidate(h.id);
    }
  }

  @Override public void openConnection(ConnectionHandle ch,
      Map<String, String> info) {
    Properties fullInfo = new Properties();
    fullInfo.putAll(this.info);
    if (info != null) {
      fullInfo.putAll(info);
    }

    final ConcurrentMap<String, Connection> cacheAsMap = connectionCache.asMap();
    if (cacheAsMap.containsKey(ch.id)) {
      throw new RuntimeException("Connection already exists: " + ch.id);
    }
    // Avoid global synchronization of connection opening
    try {
      Connection conn = createConnection(url, fullInfo);
      Connection loadedConn = cacheAsMap.putIfAbsent(ch.id, conn);
      // Race condition: someone beat us to storing the connection in the cache.
      if (loadedConn != null) {
        conn.close();
        throw new RuntimeException("Connection already exists: " + ch.id);
      }
    } catch (SQLException e) {
      throw new RuntimeException(e);
    }
  }

  // Visible for testing
  protected Connection createConnection(String url, Properties info) throws SQLException {
    // Allows simpler testing of openConnection
    return DriverManager.getConnection(url, info);
  }

  @Override public void closeConnection(ConnectionHandle ch) {
    Connection conn = connectionCache.getIfPresent(ch.id);
    if (conn == null) {
      LOG.debug("client requested close unknown connection {}", ch);
      return;
    }
    LOG.trace("closing connection {}", ch);
    try {
      conn.close();
    } catch (SQLException e) {
      throw propagate(e);
    } finally {
      connectionCache.invalidate(ch.id);
    }
  }

  protected void apply(Connection conn, ConnectionProperties connProps)
      throws SQLException {
    if (connProps.isAutoCommit() != null) {
      conn.setAutoCommit(connProps.isAutoCommit());
    }
    if (connProps.isReadOnly() != null) {
      conn.setReadOnly(connProps.isReadOnly());
    }
    if (connProps.getTransactionIsolation() != null) {
      conn.setTransactionIsolation(connProps.getTransactionIsolation());
    }
    if (connProps.getCatalog() != null) {
      conn.setCatalog(connProps.getCatalog());
    }
    if (connProps.getSchema() != null) {
      conn.setSchema(connProps.getSchema());
    }
  }

  @Override public ConnectionProperties connectionSync(ConnectionHandle ch,
      ConnectionProperties connProps) {
    LOG.trace("syncing properties for connection {}", ch);
    try {
      Connection conn = getConnection(ch.id);
      ConnectionPropertiesImpl props = new ConnectionPropertiesImpl(conn).merge(connProps);
      if (props.isDirty()) {
        apply(conn, props);
        props.setDirty(false);
      }
      return props;
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  RuntimeException propagate(Throwable e) {
    if (e instanceof RuntimeException) {
      throw (RuntimeException) e;
    } else if (e instanceof Error) {
      throw (Error) e;
    } else {
      throw new RuntimeException(e);
    }
  }

  public StatementHandle prepare(ConnectionHandle ch, String sql,
      long maxRowCount) {
    try {
      final Connection conn = getConnection(ch.id);
      final PreparedStatement statement = conn.prepareStatement(sql);
      final int id = getStatementIdGenerator().getAndIncrement();
      Meta.StatementType statementType = null;
      if (statement.isWrapperFor(AvaticaPreparedStatement.class)) {
        final AvaticaPreparedStatement avaticaPreparedStatement;
        avaticaPreparedStatement =
            statement.unwrap(AvaticaPreparedStatement.class);
        statementType = avaticaPreparedStatement.getStatementType();
      }
      // Set the maximum number of rows
      setMaxRows(statement, maxRowCount);
      getStatementCache().put(id, new StatementInfo(statement));
      StatementHandle h = new StatementHandle(ch.id, id,
          signature(statement.getMetaData(), statement.getParameterMetaData(),
              sql, statementType));
      LOG.trace("prepared statement {}", h);
      return h;
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @SuppressWarnings("deprecation")
  public ExecuteResult prepareAndExecute(StatementHandle h, String sql,
      long maxRowCount, PrepareCallback callback) throws NoSuchStatementException {
    return prepareAndExecute(h, sql, maxRowCount, AvaticaUtils.toSaturatedInt(maxRowCount),
        callback);
  }

  public ExecuteResult prepareAndExecute(StatementHandle h, String sql, long maxRowCount,
      int maxRowsInFirstFrame, PrepareCallback callback) throws NoSuchStatementException {
    try {
      final StatementInfo info = getStatementCache().getIfPresent(h.id);
      if (info == null) {
        throw new NoSuchStatementException(h);
      }
      final Statement statement = info.statement;
      // Make sure that we limit the number of rows for the query
      setMaxRows(statement, maxRowCount);
      boolean ret = statement.execute(sql);
      info.setResultSet(statement.getResultSet());
      // Either execute(sql) returned true or the resultSet was null
      assert ret || null == info.getResultSet();
      final List<MetaResultSet> resultSets = new ArrayList<>();
      if (null == info.getResultSet()) {
        // Create a special result set that just carries update count
        resultSets.add(
            JdbcResultSet.count(h.connectionId, h.id,
                AvaticaUtils.getLargeUpdateCount(statement)));
      } else {
        resultSets.add(
            JdbcResultSet.create(h.connectionId, h.id, info.getResultSet(), maxRowsInFirstFrame));
      }
      LOG.trace("prepAndExec statement {}", h);
      // TODO: review client to ensure statementId is updated when appropriate
      return new ExecuteResult(resultSets);
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  /**
   * Sets the provided maximum number of rows on the given statement.
   *
   * @param statement The JDBC Statement to operate on
   * @param maxRowCount The maximum number of rows which should be returned for the query
   */
  void setMaxRows(Statement statement, long maxRowCount) throws SQLException {
    // Special handling of maxRowCount as JDBC 0 is unlimited, our meta 0 row
    if (maxRowCount > 0) {
      AvaticaUtils.setLargeMaxRows(statement, maxRowCount);
    } else if (maxRowCount < 0) {
      statement.setMaxRows(0);
    }
  }

  public boolean syncResults(StatementHandle sh, QueryState state, long offset)
      throws NoSuchStatementException {
    try {
      final Connection conn = getConnection(sh.connectionId);
      final StatementInfo info = statementCache.getIfPresent(sh.id);
      if (null == info) {
        throw new NoSuchStatementException(sh);
      }
      final Statement statement = info.statement;
      // Let the state recreate the necessary ResultSet on the Statement
      info.setResultSet(state.invoke(conn, statement));

      if (null != info.getResultSet()) {
        // If it is non-null, try to advance to the requested offset.
        return info.advanceResultSetToOffset(info.getResultSet(), offset);
      }

      // No results, nothing to do. Client can move on.
      return false;
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  public Frame fetch(StatementHandle h, long offset, int fetchMaxRowCount) throws
      NoSuchStatementException, MissingResultsException {
    LOG.trace("fetching {} offset:{} fetchMaxRowCount:{}", h, offset, fetchMaxRowCount);
    try {
      final StatementInfo statementInfo = statementCache.getIfPresent(h.id);
      if (null == statementInfo) {
        // Statement might have expired, or never existed on this server.
        throw new NoSuchStatementException(h);
      }

      if (!statementInfo.isResultSetInitialized()) {
        // The Statement exists, but the results are missing. Need to call syncResults(...)
        throw new MissingResultsException(h);
      }
      if (statementInfo.getResultSet() == null) {
        return Frame.EMPTY;
      } else {
        return JdbcResultSet.frame(statementInfo, statementInfo.getResultSet(), offset,
            fetchMaxRowCount, calendar, Optional.<Meta.Signature>absent());
      }
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  private static String[] toArray(List<String> typeList) {
    if (typeList == null) {
      return null;
    }
    return typeList.toArray(new String[typeList.size()]);
  }

  @SuppressWarnings("deprecation")
  @Override public ExecuteResult execute(StatementHandle h, List<TypedValue> parameterValues,
      long maxRowCount) throws NoSuchStatementException {
    return execute(h, parameterValues, AvaticaUtils.toSaturatedInt(maxRowCount));
  }

  @Override public ExecuteResult execute(StatementHandle h,
      List<TypedValue> parameterValues, int maxRowsInFirstFrame) throws NoSuchStatementException {
    try {
      if (MetaImpl.checkParameterValueHasNull(parameterValues)) {
        throw new SQLException("exception while executing query: unbound parameter");
      }

      final StatementInfo statementInfo = statementCache.getIfPresent(h.id);
      if (null == statementInfo) {
        throw new NoSuchStatementException(h);
      }
      final List<MetaResultSet> resultSets;
      final PreparedStatement preparedStatement =
          (PreparedStatement) statementInfo.statement;

      if (parameterValues != null) {
        for (int i = 0; i < parameterValues.size(); i++) {
          TypedValue o = parameterValues.get(i);
          preparedStatement.setObject(i + 1, o.toJdbc(calendar));
        }
      }

      if (preparedStatement.execute()) {
        final Signature signature2;
        if (preparedStatement.isWrapperFor(AvaticaPreparedStatement.class)) {
          signature2 = h.signature;
        } else {
          h.signature = signature(preparedStatement.getMetaData(),
              preparedStatement.getParameterMetaData(), h.signature.sql,
              Meta.StatementType.SELECT);
          signature2 = h.signature;
        }

        // Make sure we set this for subsequent fetch()'s to find the result set.
        statementInfo.setResultSet(preparedStatement.getResultSet());

        if (statementInfo.getResultSet() == null) {
          resultSets = Collections.<MetaResultSet>singletonList(
              JdbcResultSet.empty(h.connectionId, h.id, signature2));
        } else {
          resultSets = Collections.<MetaResultSet>singletonList(
              JdbcResultSet.create(h.connectionId, h.id, statementInfo.getResultSet(),
                  maxRowsInFirstFrame, signature2));
        }
      } else {
        resultSets = Collections.<MetaResultSet>singletonList(
            JdbcResultSet.count(h.connectionId, h.id, preparedStatement.getUpdateCount()));
      }

      return new ExecuteResult(resultSets);
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public void commit(ConnectionHandle ch) {
    try {
      final Connection conn = getConnection(ch.id);
      conn.commit();
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public void rollback(ConnectionHandle ch) {
    try {
      final Connection conn = getConnection(ch.id);
      conn.rollback();
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public ExecuteBatchResult prepareAndExecuteBatch(StatementHandle h,
      List<String> sqlCommands) throws NoSuchStatementException {
    try {
      // Get the statement
      final StatementInfo info = statementCache.getIfPresent(h.id);
      if (info == null) {
        throw new NoSuchStatementException(h);
      }

      // addBatch() for each sql command
      final Statement stmt = info.statement;
      for (String sqlCommand : sqlCommands) {
        stmt.addBatch(sqlCommand);
      }

      // Execute the batch and return the results
      return new ExecuteBatchResult(AvaticaUtils.executeLargeBatch(stmt));
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public ExecuteBatchResult executeBatch(StatementHandle h,
      List<List<TypedValue>> updateBatches) throws NoSuchStatementException {
    try {
      final StatementInfo info = statementCache.getIfPresent(h.id);
      if (null == info) {
        throw new NoSuchStatementException(h);
      }

      final PreparedStatement preparedStmt = (PreparedStatement) info.statement;
      int rowUpdate = 1;
      for (List<TypedValue> batch : updateBatches) {
        int i = 1;
        for (TypedValue value : batch) {
          // Set the TypedValue in the PreparedStatement
          try {
            preparedStmt.setObject(i, value.toJdbc(calendar));
            i++;
          } catch (SQLException e) {
            throw new RuntimeException("Failed to set value on row #" + rowUpdate
                + " and column #" + i, e);
          }
          // Track the update number for better error messages
          rowUpdate++;
        }
        preparedStmt.addBatch();
      }
      return new ExecuteBatchResult(AvaticaUtils.executeLargeBatch(preparedStmt));
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  @Override public ExecuteBatchResult executeBatchProtobuf(StatementHandle h,
      List<Requests.UpdateBatch> updateBatches) throws NoSuchStatementException {
    try {
      final StatementInfo info = statementCache.getIfPresent(h.id);
      if (null == info) {
        throw new NoSuchStatementException(h);
      }

      final PreparedStatement preparedStmt = (PreparedStatement) info.statement;
      for (Requests.UpdateBatch update : updateBatches) {
        int i = 1;
        for (Common.TypedValue value : update.getParameterValuesList()) {
          // Use the value and then increment
          preparedStmt.setObject(i++, TypedValue.protoToJdbc(value, calendar));
        }
        preparedStmt.addBatch();
      }
      return new ExecuteBatchResult(AvaticaUtils.executeLargeBatch(preparedStmt));
    } catch (SQLException e) {
      throw propagate(e);
    }
  }

  /** Configurable statement cache settings. */
  public enum StatementCacheSettings {
    /** JDBC connection property for setting connection cache concurrency level. */
    CONCURRENCY_LEVEL(STMT_CACHE_KEY_BASE + ".concurrency", "100"),

    /** JDBC connection property for setting connection cache initial capacity. */
    INITIAL_CAPACITY(STMT_CACHE_KEY_BASE + ".initialcapacity", "1000"),

    /** JDBC connection property for setting connection cache maximum capacity. */
    MAX_CAPACITY(STMT_CACHE_KEY_BASE + ".maxcapacity", "10000"),

    /** JDBC connection property for setting connection cache expiration duration.
     *
     * <p>Used in conjunction with {@link #EXPIRY_UNIT}.</p>
     */
    EXPIRY_DURATION(STMT_CACHE_KEY_BASE + ".expirydiration", "5"),

    /** JDBC connection property for setting connection cache expiration unit.
     *
     * <p>Used in conjunction with {@link #EXPIRY_DURATION}.</p>
     */
    EXPIRY_UNIT(STMT_CACHE_KEY_BASE + ".expiryunit", TimeUnit.MINUTES.name());

    private final String key;
    private final String defaultValue;

    StatementCacheSettings(String key, String defaultValue) {
      this.key = key;
      this.defaultValue = defaultValue;
    }

    /** The configuration key for specifying this setting. */
    public String key() {
      return key;
    }

    /** The default value for this setting. */
    public String defaultValue() {
      return defaultValue;
    }
  }

  /** Configurable connection cache settings. */
  public enum ConnectionCacheSettings {
    /** JDBC connection property for setting connection cache concurrency level. */
    CONCURRENCY_LEVEL(CONN_CACHE_KEY_BASE + ".concurrency", "10"),

    /** JDBC connection property for setting connection cache initial capacity. */
    INITIAL_CAPACITY(CONN_CACHE_KEY_BASE + ".initialcapacity", "100"),

    /** JDBC connection property for setting connection cache maximum capacity. */
    MAX_CAPACITY(CONN_CACHE_KEY_BASE + ".maxcapacity", "1000"),

    /** JDBC connection property for setting connection cache expiration duration. */
    EXPIRY_DURATION(CONN_CACHE_KEY_BASE + ".expiryduration", "10"),

    /** JDBC connection property for setting connection cache expiration unit. */
    EXPIRY_UNIT(CONN_CACHE_KEY_BASE + ".expiryunit", TimeUnit.MINUTES.name());

    private final String key;
    private final String defaultValue;

    ConnectionCacheSettings(String key, String defaultValue) {
      this.key = key;
      this.defaultValue = defaultValue;
    }

    /** The configuration key for specifying this setting. */
    public String key() {
      return key;
    }

    /** The default value for this setting. */
    public String defaultValue() {
      return defaultValue;
    }
  }

  /** Callback for {@link #connectionCache} member expiration. */
  private class ConnectionExpiryHandler
      implements RemovalListener<String, Connection> {

    public void onRemoval(RemovalNotification<String, Connection> notification) {
      String connectionId = notification.getKey();
      Connection doomed = notification.getValue();
      LOG.debug("Expiring connection {} because {}", connectionId, notification.getCause());
      try {
        if (doomed != null) {
          doomed.close();
        }
      } catch (Throwable t) {
        LOG.info("Exception thrown while expiring connection {}", connectionId, t);
      }
    }
  }

  /** Callback for {@link #statementCache} member expiration. */
  private class StatementExpiryHandler
      implements RemovalListener<Integer, StatementInfo> {
    public void onRemoval(RemovalNotification<Integer, StatementInfo> notification) {
      Integer stmtId = notification.getKey();
      StatementInfo doomed = notification.getValue();
      if (doomed == null) {
        // log/throw?
        return;
      }
      LOG.debug("Expiring statement {} because {}", stmtId, notification.getCause());
      try {
        if (doomed.getResultSet() != null) {
          doomed.getResultSet().close();
        }
        if (doomed.statement != null) {
          doomed.statement.close();
        }
      } catch (Throwable t) {
        LOG.info("Exception thrown while expiring statement {}", stmtId, t);
      }
    }
  }
}

// End JdbcMeta.java