Java tutorial
/** * 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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.tajo.client.v2; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.tajo.exception.QueryFailedException; import org.apache.tajo.exception.UndefinedDatabaseException; import org.apache.tajo.client.v2.exception.ClientUnableToConnectException; import org.apache.tajo.exception.TajoException; import java.io.Closeable; import java.io.IOException; import java.sql.ResultSet; import java.util.Properties; public class TajoClient implements Closeable { private static Log LOG = LogFactory.getLog(TajoClient.class); /** * default client port number */ public static final int DEFAULT_PORT = 26002; private final ClientDelegate delegate; /** * Initialize TajoClient with a hostname and default port 26002. * * @param host hostname to connect */ public TajoClient(String host) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(host, DEFAULT_PORT, null); } /** * Initialize TajoClient with a hostname and default port 26002. * * @param host Hostname to connect * @param clientParams Client connection parameters */ public TajoClient(String host, Properties clientParams) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(host, DEFAULT_PORT, clientParams); } /** * Initialize TajoClient with a hostname and port * * @param host Hostname to connect * @param port Port number to connect */ public TajoClient(String host, int port) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(host, port, null); } /** * Initialize TajoClient with a hostname and port * * @param host Hostname to connect * @param port Port number to connect * @param clientParams Client connection parameters */ public TajoClient(String host, int port, Properties clientParams) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(host, port, clientParams); } /** * Initialize TajoClient via service discovery protocol * * @param discovery Service discovery */ public TajoClient(ServiceDiscovery discovery) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(discovery, null); } /** * Initialize TajoClient via service discovery protocol * * @param discovery Service discovery * @param clientParams Client connection parameters */ public TajoClient(ServiceDiscovery discovery, Properties clientParams) throws ClientUnableToConnectException { delegate = ClientDelegateFactory.newDefaultDelegate(discovery, clientParams); } /** * Submit and executes the given SQL statement, which may be an <code>INSERT (INTO)</code>, * or <code>CREATE TABLE AS SELECT</code> statement or anSQL statement that returns nothing, * such as an SQL DDL statement. * * @param sql a SQL statement * @return inserted row number * @throws TajoException */ public int executeUpdate(String sql) throws TajoException { return delegate.executeUpdate(sql); } /** * Submit a SQL query statement * * @param sql a SQL statement * @return QueryHandler * @throws TajoException */ public ResultSet executeQuery(String sql) throws TajoException, QueryFailedException { return delegate.executeSQL(sql); } /** * Execute a SQL statement through asynchronous API * * @param sql * @return * @throws TajoException */ public QueryFuture executeQueryAsync(String sql) throws TajoException { return delegate.executeSQLAsync(sql); } public void close() { try { delegate.close(); } catch (IOException e) { LOG.warn(e); } } /** * Select working database * * @param database Database name * @throws UndefinedDatabaseException */ public void selectDB(String database) throws UndefinedDatabaseException { delegate.selectDB(database); } /** * Get the current working database * * @return Current working database */ public String currentDB() { return delegate.currentDB(); } }