Java tutorial
/** * Copyright (C) 2013, Moss Computing Inc. * * This file is part of blankslate. * * blankslate is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2, or (at your option) * any later version. * * blankslate is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with blankslate; see the file COPYING. If not, write to the * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301 USA. * * Linking this library statically or dynamically with other modules is * making a combined work based on this library. Thus, the terms and * conditions of the GNU General Public License cover the whole * combination. * * As a special exception, the copyright holders of this library give you * permission to link this library with independent modules to produce an * executable, regardless of the license terms of these independent * modules, and to copy and distribute the resulting executable under * terms of your choice, provided that you also meet, for each linked * independent module, the terms and conditions of the license of that * module. An independent module is a module which is not derived from * or based on this library. If you modify this library, you may extend * this exception to your version of the library, but you are not * obligated to do so. If you do not wish to do so, delete this * exception statement from your version. */ package com.moss.blankslate; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import com.moss.jdbcdrivers.DatabaseType; import com.moss.jdbcdrivers.JdbcConnectionConfig; public class PostgresqlCatalogFactory extends CatalogFactory { private static final Log log = LogFactory.getLog(PostgresqlCatalogFactory.class); private static final String CONFIG_PROPERTY_KEY_HOST = "postgres.host"; private static final String CONFIG_PROPERTY_KEY_PASSWORD = "postgres.saPassword"; // Hard-coded assumptions that might need to be parameterized private static final String DEFAULT_SCHEMA_NAME = "postgres"; private static final String LOGIN = "postgres"; private static Integer sequenceNum = 1; private String hostname, password; /** * Postgres doesn't always delete a catalog immediately. See http://www.mail-archive.com/pgsql-hackers@postgresql.org/msg65284.html */ public PostgresqlCatalogFactory() { hostname = properties.getProperty(CONFIG_PROPERTY_KEY_HOST); password = properties.getProperty(CONFIG_PROPERTY_KEY_PASSWORD); } public BlankslateCatalogHandle createCatalog(boolean deleteOnExit) throws Exception { checkConfig(); String testCatalogName = "test-" + sequenceNum + "-" + getCatalogNameQualifier(); synchronized (sequenceNum) { sequenceNum++; } JdbcConnectionConfig config = new JdbcConnectionConfig(DatabaseType.DB_TYPE_POSTGRESQL, null, hostname, null, "postgres", LOGIN, password); Connection adminConnection = config.createConnection(); if (catalogExists(testCatalogName, adminConnection)) { log.warn("Database '" + testCatalogName + "' already exists... will be deleted"); deleteCatalog(testCatalogName); } // THIS IS THE CONFIGURATION FOR THE AS-YET-UNCREATED CATALOG JdbcConnectionConfig newCatalogConfig = new JdbcConnectionConfig(DatabaseType.DB_TYPE_POSTGRESQL, null, hostname, null, testCatalogName, LOGIN, password); // CREATE THE CATALOG adminConnection.createStatement().execute("CREATE DATABASE \"" + testCatalogName + "\" TEMPLATE template0"); adminConnection.close(); assertClosed(adminConnection); // CREATE THE DEFAULT SCHEMA Connection newDatabaseConnection = newCatalogConfig.createConnection(); dropSchema(DEFAULT_SCHEMA_NAME, newDatabaseConnection); newDatabaseConnection.createStatement().execute("create schema " + DEFAULT_SCHEMA_NAME + ""); newDatabaseConnection.commit(); newDatabaseConnection.close(); assertClosed(newDatabaseConnection); BlankslateCatalogHandle handle = new BlankslateCatalogHandle(testCatalogName, newCatalogConfig, DEFAULT_SCHEMA_NAME); return handle; } public List getCatalogs(Connection connection) throws SQLException { List catalogNames = new ArrayList(); Statement stmt = connection.createStatement(); ResultSet rs = stmt.executeQuery("select datname from pg_catalog.pg_database"); while (rs.next()) { String name = rs.getString(1); log.debug("Found catalog " + name); catalogNames.add(name); } rs.close(); stmt.close(); return catalogNames; } public boolean catalogExists(String catalogName, Connection connection) throws SQLException { //NOTE: postgres stores all catalog names as lowercase, regardless return getCatalogs(connection).contains(catalogName.toLowerCase()); } private void assertClosed(Connection connection) throws Exception { if (!connection.isClosed()) throw new Exception("Connection not closed!"); } private void dropSchema(String schemaName, Connection connection) throws SQLException { ResultSet schemas = connection.getMetaData().getSchemas(); boolean hasSchema = false; while (schemas.next()) { String nextSchema = schemas.getString("TABLE_SCHEM"); log.debug("Found schema " + nextSchema); if (nextSchema.equals(schemaName)) hasSchema = true; } if (hasSchema) { log.debug("Dropping schema \"" + schemaName + "\""); connection.createStatement().execute("DROP SCHEMA " + schemaName); connection.commit(); } else { log.debug("Could not find schema to drop: \"" + schemaName + "\""); } } private void checkConfig() throws ConfigurationException { if (hostname == null || LOGIN == null || password == null) { String errors = ""; if (hostname == null) errors += "\n" + CONFIG_PROPERTY_KEY_HOST; if (password == null) errors += "\n" + CONFIG_PROPERTY_KEY_PASSWORD; throw new ConfigurationException( "Missing configuration information (set these properties in ~/.blankslate/blankslate.properties or ./blankslate.properties):" + errors); } } private void deleteCatalog(String name) throws Exception { // Thread.sleep(500); JdbcConnectionConfig config = new JdbcConnectionConfig(DatabaseType.DB_TYPE_POSTGRESQL, null, hostname, null, "postgres", LOGIN, password); Connection adminConnection = config.createConnection(); adminConnection.createStatement().execute("drop database \"" + name + "\""); adminConnection.commit(); adminConnection.close(); assertClosed(adminConnection); } public void deleteCatalog(BlankslateCatalogHandle name) throws Exception { deleteCatalog(name.getName()); } }