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 * * 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.kylin.query.adhoc; import java.sql.Connection; import java.sql.SQLException; import org.apache.commons.dbcp.BasicDataSource; import org.apache.kylin.common.KylinConfig; public class JdbcPushDownConnectionManager { private volatile static JdbcPushDownConnectionManager manager = null; static JdbcPushDownConnectionManager getConnectionManager() throws ClassNotFoundException { if (manager == null) { synchronized (JdbcPushDownConnectionManager.class) { if (manager == null) { manager = new JdbcPushDownConnectionManager(KylinConfig.getInstanceFromEnv()); } } } return manager; } private final BasicDataSource dataSource; private JdbcPushDownConnectionManager(KylinConfig config) throws ClassNotFoundException { dataSource = new BasicDataSource(); Class.forName(config.getJdbcDriverClass()); dataSource.setDriverClassName(config.getJdbcDriverClass()); dataSource.setUrl(config.getJdbcUrl()); dataSource.setUsername(config.getJdbcUsername()); dataSource.setPassword(config.getJdbcPassword()); dataSource.setMaxActive(config.getPoolMaxTotal()); dataSource.setMaxIdle(config.getPoolMaxIdle()); dataSource.setMinIdle(config.getPoolMinIdle()); // Default settings dataSource.setTestOnBorrow(true); dataSource.setValidationQuery("select 1"); dataSource.setRemoveAbandoned(true); dataSource.setRemoveAbandonedTimeout(300); } public void close() { try { dataSource.close(); } catch (Exception e) { throw new RuntimeException(e); } } public void close(Connection conn) { try { conn.close(); } catch (Exception e) { throw new RuntimeException(e); } } public synchronized Connection getConnection() { try { return dataSource.getConnection(); } catch (SQLException e) { throw new RuntimeException(e); } } }