001    /*
002     * Sonar, open source software quality management tool.
003     * Copyright (C) 2008-2012 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * Sonar is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * Sonar is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public
017     * License along with Sonar; if not, write to the Free Software
018     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019     */
020    package org.sonar.batch.bootstrap;
021    
022    import java.sql.Driver;
023    import java.sql.DriverManager;
024    import java.sql.SQLException;
025    import java.util.ArrayList;
026    import java.util.Enumeration;
027    import java.util.HashSet;
028    import java.util.List;
029    
030    /**
031     * Companion of {@link JdbcDriverHolder} and allows it to deregister JDBC drivers.
032     * <p>
033     * Some hacks are involved in the loading of the class - see {@link JdbcDriverHolder#stop()},
034     * so this class can refer to classes only from java.* package and must not be referred from other classes.
035     * Placement and naming of this class and methods are very important, since it loaded and invoked via reflection.
036     * </p>
037     */
038    public class JdbcLeakPrevention {
039    
040      /**
041       * @return list of names of deregistered drivers
042       */
043      public List<String> clearJdbcDriverRegistrations() throws SQLException {
044        List<String> driverNames = new ArrayList<String>();
045        HashSet<Driver> originalDrivers = new HashSet<Driver>();
046        Enumeration<Driver> drivers = DriverManager.getDrivers();
047        while (drivers.hasMoreElements()) {
048          originalDrivers.add(drivers.nextElement());
049        }
050        drivers = DriverManager.getDrivers();
051        while (drivers.hasMoreElements()) {
052          Driver driver = drivers.nextElement();
053          if (driver.getClass().getClassLoader() != this.getClass().getClassLoader()) {
054            continue;
055          }
056          if (originalDrivers.contains(driver)) {
057            driverNames.add(driver.getClass().getCanonicalName());
058          }
059          DriverManager.deregisterDriver(driver);
060        }
061        return driverNames;
062      }
063    
064    }