ExploreConnection.java

/*
 * Copyright © 2014 Cask Data, Inc.
 *
 * Licensed 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 co.cask.cdap.explore.jdbc;

import co.cask.cdap.explore.client.ExploreClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.sql.Array;
import java.sql.Blob;
import java.sql.CallableStatement;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.NClob;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLClientInfoException;
import java.sql.SQLException;
import java.sql.SQLFeatureNotSupportedException;
import java.sql.SQLWarning;
import java.sql.SQLXML;
import java.sql.Savepoint;
import java.sql.Statement;
import java.sql.Struct;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.Executor;

/**
 * Explore JDBC connection.
 *
 * Closing a connection will affect executing statements, but the results of those already executed
 * will still be available.
 */
public class ExploreConnection implements Connection {
  private static final Logger LOG = LoggerFactory.getLogger(ExploreConnection.class);

  private final String namespace;
  private final ExploreConnectionParams connectionParams;
  private ExploreClient exploreClient;
  private boolean isClosed = false;

  ExploreConnection(ExploreClient exploreClient, String namespace, ExploreConnectionParams connectionParams) {
    this.exploreClient = exploreClient;
    this.namespace = namespace;
    this.connectionParams = connectionParams;
  }

  @Override
  public Statement createStatement() throws SQLException {
    if (isClosed) {
      throw new SQLException("Can't create Statement, connection is closed");
    }
    Statement statement = new ExploreStatement(this, exploreClient, namespace);
    statement.setFetchSize(connectionParams.getFetchSize());
    return statement;
  }

  @Override
  public PreparedStatement prepareStatement(String sql) throws SQLException {
    if (isClosed) {
      throw new SQLException("Can't create Statement, connection is closed");
    }
    PreparedStatement preparedStatement = new ExplorePreparedStatement(this, exploreClient, sql, namespace);
    preparedStatement.setFetchSize(connectionParams.getFetchSize());
    return preparedStatement;
  }

  @Override
  public Statement createStatement(int resultSetType, int resultSetConcurrency) throws SQLException {
    // TYPE_SCROLL_INSENSITIVE is accepted here for integration purposes,
    // but the result set type will still be TYPE_FORWARD_ONLY
    if ((resultSetType == ResultSet.TYPE_FORWARD_ONLY || resultSetType == ResultSet.TYPE_SCROLL_INSENSITIVE) &&
      resultSetConcurrency == ResultSet.CONCUR_READ_ONLY) {
      return createStatement();
    }
    throw new SQLFeatureNotSupportedException("Statement with result set type " + resultSetType +
                                                " and resultset concurrency " + resultSetConcurrency +
                                                " is not supported");
  }

  @Override
  public PreparedStatement prepareStatement(String s, int resultSetType, int resultSetConcurrency)
    throws SQLException {
    // TYPE_SCROLL_INSENSITIVE is accepted here for integration purposes,
    // but the result set type will still be TYPE_FORWARD_ONLY
    if ((resultSetType == ResultSet.TYPE_FORWARD_ONLY || resultSetType == ResultSet.TYPE_SCROLL_INSENSITIVE) &&
      resultSetConcurrency == ResultSet.CONCUR_READ_ONLY) {
      return prepareStatement(s);
    }
    throw new SQLFeatureNotSupportedException("Statement with result set type " + resultSetType +
                                                " and resultset concurrency " + resultSetConcurrency +
                                                " is not supported");
  }

  @Override
  public DatabaseMetaData getMetaData() throws SQLException {
    if (isClosed) {
      throw new SQLException("Connection is closed");
    }
    return new ExploreDatabaseMetaData(this, exploreClient);
  }

  @Override
  public void close() throws SQLException {
    try {
      exploreClient.close();
    } catch (IOException e) {
      LOG.error("Could not close explore client", e);
      throw new SQLException(e);
    } finally {
      // Free resources
      isClosed = true;
      exploreClient = null;
    }
  }

  @Override
  public boolean isClosed() throws SQLException {
    return isClosed;
  }

  @Override
  public boolean isReadOnly() throws SQLException {
    // Explore does not support writing to datasets using SQL queries
    return true;
  }

  @Override
  public boolean getAutoCommit() throws SQLException {
    // We don't (yet) support write, but with Hive, every statement is auto commit.
    return true;
  }

  @Override
  public String getCatalog() throws SQLException {
    // Hive does not have a notion of catalog - it only knows "schemas", ie databases
    return "";
  }

  @Override
  public int getTransactionIsolation() throws SQLException {
    return Connection.TRANSACTION_NONE;
  }

  @Override
  public CallableStatement prepareCall(String s) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public String nativeSQL(String s) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setAutoCommit(boolean b) throws SQLException {
    if (!b) {
      throw new SQLFeatureNotSupportedException("Explore only supports auto commit = true");
    }
  }

  @Override
  public void commit() throws SQLException {
    // no-op
  }

  @Override
  public void rollback() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setReadOnly(boolean b) throws SQLException {
    if (!b) {
      throw new SQLFeatureNotSupportedException("Explore only supports read only = true");
    }
  }

  @Override
  public void setCatalog(String s) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setTransactionIsolation(int i) throws SQLException {
    // no-op
  }

  @Override
  public SQLWarning getWarnings() throws SQLException {
    return null;
  }

  @Override
  public void clearWarnings() throws SQLException {
    // no-op
  }

  @Override
  public CallableStatement prepareCall(String s, int i, int i2) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Map<String, Class<?>> getTypeMap() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setTypeMap(Map<String, Class<?>> stringClassMap) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setHoldability(int i) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public int getHoldability() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Savepoint setSavepoint() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Savepoint setSavepoint(String s) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void rollback(Savepoint savepoint) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void releaseSavepoint(Savepoint savepoint) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability)
      throws SQLException {
    // The resultSetType can only be TYPE_FORWARD_ONLY and concurrency CONCUR_READ_ONLY,
    // and holdability is not supported yet
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public PreparedStatement prepareStatement(String s, int resultSetType, int resultSetConcurrency,
                                            int resultSetHoldability) throws SQLException {
    // The resultSetType can only be TYPE_FORWARD_ONLY and concurrency CONCUR_READ_ONLY,
    // and holdability is not supported yet
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public CallableStatement prepareCall(String s, int i, int i2, int i3) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public PreparedStatement prepareStatement(String s, int i) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public PreparedStatement prepareStatement(String s, int[] ints) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public PreparedStatement prepareStatement(String s, String[] strings) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Clob createClob() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Blob createBlob() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public NClob createNClob() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public SQLXML createSQLXML() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public boolean isValid(int i) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public void setClientInfo(String s, String s2) throws SQLClientInfoException {
    throw new SQLClientInfoException("Method not supported", null);
  }

  @Override
  public void setClientInfo(Properties properties) throws SQLClientInfoException {
    throw new SQLClientInfoException("Method not supported", null);
  }

  @Override
  public String getClientInfo(String s) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Properties getClientInfo() throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Array createArrayOf(String s, Object[] objects) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public Struct createStruct(String s, Object[] objects) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public <T> T unwrap(Class<T> tClass) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  @Override
  public boolean isWrapperFor(Class<?> aClass) throws SQLException {
    throw new SQLFeatureNotSupportedException();
  }

  public int getNetworkTimeout() throws SQLException {
    // JDK 1.7
    throw new SQLFeatureNotSupportedException();
  }

  public void setNetworkTimeout(Executor executor, int milliseconds) throws SQLException {
    // JDK 1.7
    throw new SQLFeatureNotSupportedException();
  }

  public String getSchema() throws SQLException {
    // JDK 1.7
    throw new SQLFeatureNotSupportedException();
  }

  public void setSchema(String schema) throws SQLException {
    // JDK 1.7
    throw new SQLFeatureNotSupportedException();
  }

  public void abort(Executor executor) throws SQLException {
    // JDK 1.7
    throw new SQLFeatureNotSupportedException();
  }
}