fixes mybatis/migration#1 Drivers loaded at runtime via driverClassLoader were not registered correctly.

Author: harawata

src/main/java/org/apache/ibatis/datasource/unpooled/UnpooledDataSource.java

@@ -17,9 +17,14 @@
 
 import java.io.PrintWriter;
 import java.sql.Connection;
+import java.sql.Driver;
 import java.sql.DriverManager;
+import java.sql.DriverPropertyInfo;
 import java.sql.SQLException;
+import java.util.Enumeration;
+import java.util.Map;
 import java.util.Properties;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Logger;
 
 import javax.sql.DataSource;
@@ -30,7 +35,7 @@ public class UnpooledDataSource implements DataSource {
 
   private ClassLoader driverClassLoader;
   private Properties driverProperties;
-  private boolean driverInitialized;
+  private static Map<String, Driver> driverCache = new ConcurrentHashMap<String, Driver>();
 
   private String driver;
   private String url;
@@ -41,7 +46,11 @@ public class UnpooledDataSource implements DataSource {
   private Integer defaultTransactionIsolationLevel;
 
   static {
-    DriverManager.getDrivers();
+    Enumeration<Driver> drivers = DriverManager.getDrivers();
+    while (drivers.hasMoreElements()) {
+      Driver driver = drivers.nextElement();
+      driverCache.put(driver.getClass().getName(), driver);
+    }
   }
 
   public UnpooledDataSource() {
@@ -121,7 +130,6 @@ public String getDriver() {
 
   public synchronized void setDriver(String driver) {
     this.driver = driver;
-    driverInitialized = false;
   }
 
   public String getUrl() {
@@ -183,14 +191,18 @@ private Connection doGetConnection(Properties properties) throws SQLException {
   }
 
   private synchronized void initializeDriver() throws SQLException {
-    if (!driverInitialized) {
-      driverInitialized = true;
+    if (!driverCache.containsKey(driver)) {
+      Class<?> driverType;
       try {
         if (driverClassLoader != null) {
-          Class.forName(driver, true, driverClassLoader);
+          driverType = Class.forName(driver, true, driverClassLoader);
         } else {
-          Resources.classForName(driver);
+          driverType = Resources.classForName(driver);
         }
+        // http://www.kfu.com/~nsayer/Java/dyn-jdbc.html
+        Driver driverInstance = (Driver)driverType.newInstance();
+        DriverManager.registerDriver(new DriverProxy(driverInstance));
+        driverCache.put(driver, driverInstance);
       } catch (Exception e) {
         throw new SQLException("Error setting driver on UnpooledDataSource. Cause: " + e);
       }
@@ -206,6 +218,38 @@ private void configureConnection(Connection conn) throws SQLException {
     }
   }
 
+  private static class DriverProxy implements Driver {
+    private Driver driver;
+
+    DriverProxy(Driver d) {
+      this.driver = d;
+    }
+
+    public boolean acceptsURL(String u) throws SQLException {
+      return this.driver.acceptsURL(u);
+    }
+
+    public Connection connect(String u, Properties p) throws SQLException {
+      return this.driver.connect(u, p);
+    }
+
+    public int getMajorVersion() {
+      return this.driver.getMajorVersion();
+    }
+
+    public int getMinorVersion() {
+      return this.driver.getMinorVersion();
+    }
+
+    public DriverPropertyInfo[] getPropertyInfo(String u, Properties p) throws SQLException {
+      return this.driver.getPropertyInfo(u, p);
+    }
+
+    public boolean jdbcCompliant() {
+      return this.driver.jdbcCompliant();
+    }
+  }
+
   public <T> T unwrap(Class<T> iface) throws SQLException {
     throw new SQLException(getClass().getName() + " is not a wrapper.");
   }

src/test/java/org/apache/ibatis/datasource/unpooled/UnpooledDataSourceTest.java

@@ -0,0 +1,70 @@
+/*-
+ *    Copyright 2009-2013 the original author or authors.
+ *
+ *    Licensed 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.ibatis.datasource.unpooled;
+
+import static org.junit.Assert.*;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.sql.Driver;
+import java.sql.DriverManager;
+import java.util.Enumeration;
+
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class UnpooledDataSourceTest {
+
+  @Test
+  public void shouldNotRegisterTheSameDriverMultipleTimes() throws Exception {
+    // https://code.google.com/p/mybatis/issues/detail?id=430
+    UnpooledDataSource dataSource = null;
+    dataSource = new UnpooledDataSource("org.hsqldb.jdbcDriver", "jdbc:hsqldb:mem:multipledrivers", "sa", "");
+    dataSource.getConnection();
+    int before = countRegisteredDrivers();
+    dataSource = new UnpooledDataSource("org.hsqldb.jdbcDriver", "jdbc:hsqldb:mem:multipledrivers", "sa", "");
+    dataSource.getConnection();
+    assertEquals(before, countRegisteredDrivers());
+  }
+
+  @Ignore("Requires MySQL server and a driver.")
+  @Test
+  public void shouldRegisterDynamicallyLoadedDriver() throws Exception {
+    int before = countRegisteredDrivers();
+    ClassLoader driverClassLoader = null;
+    UnpooledDataSource dataSource = null;
+    driverClassLoader = new URLClassLoader(new URL[] { new URL("jar:file:/PATH_TO/mysql-connector-java-5.1.25.jar!/") });
+    dataSource = new UnpooledDataSource(driverClassLoader, "com.mysql.jdbc.Driver", "jdbc:mysql://127.0.0.1/test", "root", "");
+    dataSource.getConnection();
+    assertEquals(before + 1, countRegisteredDrivers());
+    driverClassLoader = new URLClassLoader(new URL[] { new URL("jar:file:/PATH_TO/mysql-connector-java-5.1.25.jar!/") });
+    dataSource = new UnpooledDataSource(driverClassLoader, "com.mysql.jdbc.Driver", "jdbc:mysql://127.0.0.1/test", "root", "");
+    dataSource.getConnection();
+    assertEquals(before + 1, countRegisteredDrivers());
+  }
+
+  protected int countRegisteredDrivers() {
+    Enumeration<Driver> drivers = DriverManager.getDrivers();
+    int count = 0;
+    while (drivers.hasMoreElements()) {
+      Driver driver = drivers.nextElement();
+      System.out.println(driver.getClass().getName());
+      count++;
+    }
+    return count;
+  }
+
+}