1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/java/jdbc-dk-driver/src/main/java/info/globalcode/sql/dk/jdbc/Driver.java Mon Mar 04 22:02:52 2019 +0100
1.3 @@ -0,0 +1,157 @@
1.4 +/**
1.5 + * SQL-DK
1.6 + * Copyright © 2015 František Kučera (frantovo.cz)
1.7 + *
1.8 + * This program is free software: you can redistribute it and/or modify
1.9 + * it under the terms of the GNU General Public License as published by
1.10 + * the Free Software Foundation, either version 3 of the License, or
1.11 + * (at your option) any later version.
1.12 + *
1.13 + * This program is distributed in the hope that it will be useful,
1.14 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.15 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.16 + * GNU General Public License for more details.
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License
1.19 + * along with this program. If not, see <http://www.gnu.org/licenses/>.
1.20 + */
1.21 +package info.globalcode.sql.dk.jdbc;
1.22 +
1.23 +import info.globalcode.sql.dk.Constants;
1.24 +import info.globalcode.sql.dk.configuration.Configuration;
1.25 +import info.globalcode.sql.dk.configuration.ConfigurationException;
1.26 +import info.globalcode.sql.dk.configuration.DatabaseDefinition;
1.27 +import info.globalcode.sql.dk.configuration.Loader;
1.28 +import info.globalcode.sql.dk.configuration.Properties;
1.29 +import info.globalcode.sql.dk.configuration.Property;
1.30 +import java.sql.Connection;
1.31 +import java.sql.DriverManager;
1.32 +import java.sql.DriverPropertyInfo;
1.33 +import java.sql.SQLException;
1.34 +import java.sql.SQLFeatureNotSupportedException;
1.35 +import java.util.logging.Level;
1.36 +import java.util.logging.Logger;
1.37 +
1.38 +/**
1.39 + * <p>
1.40 + * Meta JDBC driver that works as redirector/router. It loads SQL-DK's configuration file and
1.41 + * instantiates a real JDBC connection (PostgreSQL, MariDB etc.) of given name.
1.42 + * </p>
1.43 + *
1.44 + * <p>
1.45 + * Raison d'être: user can define his/her database connections just once (in SQL-DK's configuration)
1.46 + * and use them in many other programs – there is no need to define the connection (hostname,
1.47 + * username, password, properties…) in each application again and again. User will simply connect to
1.48 + * e.g. <code>jdbc:sql-dk://my-connection</code> and this driver reads parameters of
1.49 + * <code>my-connection</code> from SQL-DK's configuration and returns real driver implementation.
1.50 + * </p>
1.51 + *
1.52 + * <p>
1.53 + * Of course, the real JDBC driver for given database is still needed on the class path.
1.54 + * </p>
1.55 + *
1.56 + * <p>
1.57 + * TODO: current version is quite heavy-weight, because it includes whole SQL-DK source tree. Some
1.58 + * refactoring and separation is desired to provide more light-weight JDBC driver. However the
1.59 + * public interface and behavior of this driver should remain unchanged.
1.60 + * </p>
1.61 + *
1.62 + * @author Ing. František Kučera (frantovo.cz)
1.63 + */
1.64 +public class Driver implements java.sql.Driver {
1.65 +
1.66 + private static final Logger log = Logger.getLogger(Driver.class.getName());
1.67 +
1.68 + private final Loader loader = new Loader();
1.69 +
1.70 + static {
1.71 + try {
1.72 + DriverManager.registerDriver(new Driver());
1.73 + } catch (SQLException e) {
1.74 + log.log(Level.SEVERE, "Unable to register JDBC driver", e);
1.75 + }
1.76 + }
1.77 +
1.78 + @Override
1.79 + public Connection connect(String url, java.util.Properties info) throws SQLException {
1.80 + if (acceptsURL(url)) {
1.81 + log.log(Level.FINER, "Loading SQL-DK configuration for URL: {0}", url);
1.82 + String name = extractDatabaseName(url);
1.83 + log.log(Level.FINE, "Loading SQL-DK configuration for name: {0}", name);
1.84 +
1.85 + try {
1.86 + return getConnection(name, info);
1.87 + } catch (ConfigurationException e) {
1.88 + log.log(Level.SEVERE, "Unable to load SQL-DK configuration for name: {0}. Is it defined in {1}?", new Object[]{name, Constants.CONFIG_FILE});
1.89 + throw new SQLException("Unable to load SQL-DK configuration for name: " + name, e);
1.90 + }
1.91 + } else {
1.92 + // The driver should return "null" if it realizes it is the wrong kind of driver to connect to the given URL.
1.93 + return null;
1.94 + }
1.95 + }
1.96 +
1.97 + private Connection getConnection(String connectionName, java.util.Properties info) throws SQLException, ConfigurationException {
1.98 + Configuration c = loader.loadConfiguration();
1.99 + DatabaseDefinition dd = c.getDatabase(connectionName);
1.100 +
1.101 + if (acceptsURL(dd.getUrl())) {
1.102 + log.log(Level.SEVERE, "SQL-DK meta JDBC driver loops to itself: {0} → {1} Please check {2}", new Object[]{connectionName, dd.getUrl(), Constants.CONFIG_FILE});
1.103 + throw new ConfigurationException("SQL-DK meta JDBC driver loops to itself.");
1.104 + } else {
1.105 + return Loader.jdbcConnect(dd, translate(info));
1.106 + }
1.107 + }
1.108 +
1.109 + private String extractDatabaseName(String url) {
1.110 + return url.split("//", 2)[1];
1.111 + }
1.112 +
1.113 + /**
1.114 + * TODO: refactor/move, reuse
1.115 + *
1.116 + * @param info
1.117 + * @return
1.118 + */
1.119 + private Properties translate(java.util.Properties info) {
1.120 + Properties properties = new Properties();
1.121 +
1.122 + for (String name : info.stringPropertyNames()) {
1.123 + String value = info.getProperty(name);
1.124 + properties.add(new Property(name, value));
1.125 + }
1.126 +
1.127 + return properties;
1.128 + }
1.129 +
1.130 + @Override
1.131 + public boolean acceptsURL(String url) throws SQLException {
1.132 + return url != null && url.startsWith("jdbc:sql-dk://");
1.133 + }
1.134 +
1.135 + @Override
1.136 + public DriverPropertyInfo[] getPropertyInfo(String url, java.util.Properties info) throws SQLException {
1.137 + return new DriverPropertyInfo[0];
1.138 + }
1.139 +
1.140 + @Override
1.141 + public int getMajorVersion() {
1.142 + return 0;
1.143 + }
1.144 +
1.145 + @Override
1.146 + public int getMinorVersion() {
1.147 + return 1;
1.148 + }
1.149 +
1.150 + @Override
1.151 + public boolean jdbcCompliant() {
1.152 + return false;
1.153 + }
1.154 +
1.155 + @Override
1.156 + public Logger getParentLogger() throws SQLFeatureNotSupportedException {
1.157 + throw new SQLFeatureNotSupportedException("Not supported yet.");
1.158 + }
1.159 +
1.160 +}