/*
* Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package java.sql;
import java.util.Iterator;
import java.sql.Driver;
import java.util.ServiceLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* <P>The basic service for managing a set of JDBC drivers.<br>
* <B>NOTE:</B> The {@link <code>DataSource</code>} interface, new in the
* JDBC 2.0 API, provides another way to connect to a data source.
* The use of a <code>DataSource</code> object is the preferred means of
* connecting to a data source.
*
* <P>As part of its initialization, the <code>DriverManager</code> class will
* attempt to load the driver classes referenced in the "jdbc.drivers"
* system property. This allows a user to customize the JDBC Drivers
* used by their applications. For example in your
* ~/.hotjava/properties file you might specify:
* <pre>
* <CODE>jdbc.drivers=foo.bah.Driver:wombat.sql.Driver:bad.taste.ourDriver</CODE>
* </pre>
*<P> The <code>DriverManager</code> methods <code>getConnection</code> and
* <code>getDrivers</code> have been enhanced to support the Java Standard Edition
* <a href="../../../technotes/guides/jar/jar.html#Service%20Provider">Service Provider</a> mechanism. JDBC 4.0 Drivers must
* include the file <code>META-INF/services/java.sql.Driver</code>. This file contains the name of the JDBC drivers
* implementation of <code>java.sql.Driver</code>. For example, to load the <code>my.sql.Driver</code> class,
* the <code>META-INF/services/java.sql.Driver</code> file would contain the entry:
* <pre>
* <code>my.sql.Driver</code>
* </pre>
*
* <P>Applications no longer need to explictly load JDBC drivers using <code>Class.forName()</code>. Existing programs
* which currently load JDBC drivers using <code>Class.forName()</code> will continue to work without
* modification.
*
* <P>When the method <code>getConnection</code> is called,
* the <code>DriverManager</code> will attempt to
* locate a suitable driver from amongst those loaded at
* initialization and those loaded explicitly using the same classloader
* as the current applet or application.
*
* <P>
* Starting with the Java 2 SDK, Standard Edition, version 1.3, a
* logging stream can be set only if the proper
* permission has been granted. Normally this will be done with
* the tool PolicyTool, which can be used to grant <code>permission
* java.sql.SQLPermission "setLog"</code>.
* @see Driver
* @see Connection
*/
public class DriverManager {
/**
* The <code>SQLPermission</code> constant that allows the
* setting of the logging stream.
* @since 1.3
*/
final static SQLPermission SET_LOG_PERMISSION =
new SQLPermission("setLog");
//--------------------------JDBC 2.0-----------------------------
/**
* Retrieves the log writer.
*
* The <code>getLogWriter</code> and <code>setLogWriter</code>
* methods should be used instead
* of the <code>get/setlogStream</code> methods, which are deprecated.
* @return a <code>java.io.PrintWriter</code> object
* @see #setLogWriter
* @since 1.2
*/
public static java.io.PrintWriter getLogWriter() {
return logWriter;
}
/**
* Sets the logging/tracing <code>PrintWriter</code> object
* that is used by the <code>DriverManager</code> and all drivers.
* <P>
* There is a minor versioning problem created by the introduction
* of the method <code>setLogWriter</code>. The
* method <code>setLogWriter</code> cannot create a <code>PrintStream</code> object
* that will be returned by <code>getLogStream</code>---the Java platform does
* not provide a backward conversion. As a result, a new application
* that uses <code>setLogWriter</code> and also uses a JDBC 1.0 driver that uses
* <code>getLogStream</code> will likely not see debugging information written
* by that driver.
*<P>
* Starting with the Java 2 SDK, Standard Edition, version 1.3 release, this method checks
* to see that there is an <code>SQLPermission</code> object before setting
* the logging stream. If a <code>SecurityManager</code> exists and its
* <code>checkPermission</code> method denies setting the log writer, this
* method throws a <code>java.lang.SecurityException</code>.
*
* @param out the new logging/tracing <code>PrintStream</code> object;
* <code>null</code> to disable logging and tracing
* @throws SecurityException
* if a security manager exists and its
* <code>checkPermission</code> method denies
* setting the log writer
*
* @see SecurityManager#checkPermission
* @see #getLogWriter
* @since 1.2
*/
public static void setLogWriter(java.io.PrintWriter out) {
SecurityManager sec = System.getSecurityManager();
if (sec != null) {
sec.checkPermission(SET_LOG_PERMISSION);
}
logStream = null;
logWriter = out;
}
//---------------------------------------------------------------
/**
* Attempts to establish a connection to the given database URL.
* The <code>DriverManager</code> attempts to select an appropriate driver from
* the set of registered JDBC drivers.
*
* @param url a database url of the form
* <code> jdbc:<em>subprotocol</em>:<em>subname</em></code>
* @param info a list of arbitrary string tag/value pairs as
* connection arguments; normally at least a "user" and
* "password" property should be included
* @return a Connection to the URL
* @exception SQLException if a database access error occurs
*/
public static Connection getConnection(String url,
java.util.Properties info) throws SQLException {
// Gets the classloader of the code that called this method, may
// be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
return (getConnection(url, info, callerCL));
}
/**
* Attempts to establish a connection to the given database URL.
* The <code>DriverManager</code> attempts to select an appropriate driver from
* the set of registered JDBC drivers.
*
* @param url a database url of the form
* <code>jdbc:<em>subprotocol</em>:<em>subname</em></code>
* @param user the database user on whose behalf the connection is being
* made
* @param password the user's password
* @return a connection to the URL
* @exception SQLException if a database access error occurs
*/
public static Connection getConnection(String url,
String user, String password) throws SQLException {
java.util.Properties info = new java.util.Properties();
// Gets the classloader of the code that called this method, may
// be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
if (user != null) {
info.put("user", user);
}
if (password != null) {
info.put("password", password);
}
return (getConnection(url, info, callerCL));
}
/**
* Attempts to establish a connection to the given database URL.
* The <code>DriverManager</code> attempts to select an appropriate driver from
* the set of registered JDBC drivers.
*
* @param url a database url of the form
* <code> jdbc:<em>subprotocol</em>:<em>subname</em></code>
* @return a connection to the URL
* @exception SQLException if a database access error occurs
*/
public static Connection getConnection(String url)
throws SQLException {
java.util.Properties info = new java.util.Properties();
// Gets the classloader of the code that called this method, may
// be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
return (getConnection(url, info, callerCL));
}
/**
* Attempts to locate a driver that understands the given URL.
* The <code>DriverManager</code> attempts to select an appropriate driver from
* the set of registered JDBC drivers.
*
* @param url a database URL of the form
* <code>jdbc:<em>subprotocol</em>:<em>subname</em></code>
* @return a <code>Driver</code> object representing a driver
* that can connect to the given URL
* @exception SQLException if a database access error occurs
*/
public static Driver getDriver(String url)
throws SQLException {
java.util.Vector drivers = null;
println("DriverManager.getDriver(\"" + url + "\")");
if (!initialized) {
initialize();
}
synchronized (DriverManager.class){
// use the read copy of the drivers vector
drivers = readDrivers;
}
// Gets the classloader of the code that called this method, may
// be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
// Walk through the loaded drivers attempting to locate someone
// who understands the given URL.
for (int i = 0; i < drivers.size(); i++) {
DriverInfo di = (DriverInfo)drivers.elementAt(i);
// If the caller does not have permission to load the driver then
// skip it.
if ( getCallerClass(callerCL, di.driverClassName ) !=
di.driverClass ) {
println(" skipping: " + di);
continue;
}
try {
println(" trying " + di);
if (di.driver.acceptsURL(url)) {
// Success!
println("getDriver returning " + di);
return (di.driver);
}
} catch (SQLException ex) {
// Drop through and try the next driver.
}
}
println("getDriver: no suitable driver");
throw new SQLException("No suitable driver", "08001");
}
/**
* Registers the given driver with the <code>DriverManager</code>.
* A newly-loaded driver class should call
* the method <code>registerDriver</code> to make itself
* known to the <code>DriverManager</code>.
*
* @param driver the new JDBC Driver that is to be registered with the
* <code>DriverManager</code>
* @exception SQLException if a database access error occurs
*/
public static synchronized void registerDriver(java.sql.Driver driver)
throws SQLException {
if (!initialized) {
initialize();
}
DriverInfo di = new DriverInfo();
di.driver = driver;
di.driverClass = driver.getClass();
di.driverClassName = di.driverClass.getName();
// Not Required -- drivers.addElement(di);
writeDrivers.addElement(di);
println("registerDriver: " + di);
/* update the read copy of drivers vector */
readDrivers = (java.util.Vector) writeDrivers.clone();
}
/**
* Drops a driver from the <code>DriverManager</code>'s list.
* Applets can only deregister drivers from their own classloaders.
*
* @param driver the JDBC Driver to drop
* @exception SQLException if a database access error occurs
*/
public static synchronized void deregisterDriver(Driver driver)
throws SQLException {
// Gets the classloader of the code that called this method,
// may be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
println("DriverManager.deregisterDriver: " + driver);
// Walk through the loaded drivers.
int i;
DriverInfo di = null;
for (i = 0; i < writeDrivers.size(); i++) {
di = (DriverInfo)writeDrivers.elementAt(i);
if (di.driver == driver) {
break;
}
}
// If we can't find the driver just return.
if (i >= writeDrivers.size()) {
println(" couldn't find driver to unload");
return;
}
// If the caller does not have permission to load the driver then
// throw a security exception.
if (getCallerClass(callerCL, di.driverClassName ) != di.driverClass ) {
throw new SecurityException();
}
// Remove the driver. Other entries in drivers get shuffled down.
writeDrivers.removeElementAt(i);
/* update the read copy of drivers vector */
readDrivers = (java.util.Vector) writeDrivers.clone();
}
/**
* Retrieves an Enumeration with all of the currently loaded JDBC drivers
* to which the current caller has access.
*
* <P><B>Note:</B> The classname of a driver can be found using
* <CODE>d.getClass().getName()</CODE>
*
* @return the list of JDBC Drivers loaded by the caller's class loader
*/
public static java.util.Enumeration<Driver> getDrivers() {
java.util.Vector<Driver> result = new java.util.Vector<Driver>();
java.util.Vector drivers = null;
if (!initialized) {
initialize();
}
synchronized (DriverManager.class){
// use the readcopy of drivers
drivers = readDrivers;
}
// Gets the classloader of the code that called this method, may
// be null.
ClassLoader callerCL = DriverManager.getCallerClassLoader();
// Walk through the loaded drivers.
for (int i = 0; i < drivers.size(); i++) {
DriverInfo di = (DriverInfo)drivers.elementAt(i);
// If the caller does not have permission to load the driver then
// skip it.
if ( getCallerClass(callerCL, di.driverClassName ) != di.driverClass ) {
println(" skipping: " + di);
continue;
}
result.addElement(di.driver);
}
return (result.elements());
}
/**
* Sets the maximum time in seconds that a driver will wait
* while attempting to connect to a database.
*
* @param seconds the login time limit in seconds; zero means there is no limit
* @see #getLoginTimeout
*/
public static void setLoginTimeout(int seconds) {
loginTimeout = seconds;
}
/**
* Gets the maximum time in seconds that a driver can wait
* when attempting to log in to a database.
*
* @return the driver login time limit in seconds
* @see #setLoginTimeout
*/
public static int getLoginTimeout() {
return (loginTimeout);
}
/**
* Sets the logging/tracing PrintStream that is used
* by the <code>DriverManager</code>
* and all drivers.
*<P>
* In the Java 2 SDK, Standard Edition, version 1.3 release, this method checks
* to see that there is an <code>SQLPermission</code> object before setting
* the logging stream. If a <code>SecurityManager</code> exists and its
* <code>checkPermission</code> method denies setting the log writer, this
* method throws a <code>java.lang.SecurityException</code>.
*
* @param out the new logging/tracing PrintStream; to disable, set to <code>null</code>
* @deprecated
* @throws SecurityException if a security manager exists and its
* <code>checkPermission</code> method denies setting the log stream
*
* @see SecurityManager#checkPermission
* @see #getLogStream
*/
public static void setLogStream(java.io.PrintStream out) {
SecurityManager sec = System.getSecurityManager();
if (sec != null) {
sec.checkPermission(SET_LOG_PERMISSION);
}
logStream = out;
if ( out != null )
logWriter = new java.io.PrintWriter(out);
else
logWriter = null;
}
/**
* Retrieves the logging/tracing PrintStream that is used by the <code>DriverManager</code>
* and all drivers.
*
* @return the logging/tracing PrintStream; if disabled, is <code>null</code>
* @deprecated
* @see #setLogStream
*/
public static java.io.PrintStream getLogStream() {
return logStream;
}
/**
* Prints a message to the current JDBC log stream.
*
* @param message a log or tracing message
*/
public static void println(String message) {
synchronized (logSync) {
if (logWriter != null) {
logWriter.println(message);
// automatic flushing is never enabled, so we must do it ourselves
logWriter.flush();
}
}
}
//------------------------------------------------------------------------
// Returns the class object that would be created if the code calling the
// driver manager had loaded the driver class, or null if the class
// is inaccessible.
private static Class getCallerClass(ClassLoader callerClassLoader,
String driverClassName) {
Class callerC = null;
try {
callerC = Class.forName(driverClassName, true, callerClassLoader);
}
catch (Exception ex) {
callerC = null; // being very careful
}
return callerC;
}
private static void loadInitialDrivers() {
String drivers;
try {
drivers = (String) AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
return System.getProperty("jdbc.drivers");
}
});
} catch (Exception ex) {
drivers = null;
}
// If the driver is packaged as a Service Provider, load it.
// Get all the drivers through the classloader
// exposed as a java.sql.Driver.class service.
// ServiceLoader.load() replaces the sun.misc.Providers()
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
ServiceLoader<Driver> loadedDrivers = ServiceLoader.load(Driver.class);
Iterator driversIterator = loadedDrivers.iterator();
/* Load these drivers, so that they can be instantiated.
* It may be the case that the driver class may not be there
* i.e. there may be a packaged driver with the service class
* as implementation of java.sql.Driver but the actual class
* may be missing. In that case a java.util.ServiceConfigurationError
* will be thrown at runtime by the VM trying to locate
* and load the service.
*
* Adding a try catch block to catch those runtime errors
* if driver not available in classpath but it's
* packaged as service and that service is there in classpath.
*/
try{
while(driversIterator.hasNext()) {
println(" Loading done by the java.util.ServiceLoader : "+driversIterator.next());
}
} catch(Throwable t) {
// Do nothing
}
return null;
}
});
println("DriverManager.initialize: jdbc.drivers = " + drivers);
if (drivers == null) {
return;
}
while (drivers.length() != 0) {
int x = drivers.indexOf(':');
String driver;
if (x < 0) {
driver = drivers;
drivers = "";
} else {
driver = drivers.substring(0, x);
drivers = drivers.substring(x+1);
}
if (driver.length() == 0) {
continue;
}
try {
println("DriverManager.Initialize: loading " + driver);
Class.forName(driver, true,
ClassLoader.getSystemClassLoader());
} catch (Exception ex) {
println("DriverManager.Initialize: load failed: " + ex);
}
}
}
// Worker method called by the public getConnection() methods.
private static Connection getConnection(
String url, java.util.Properties info, ClassLoader callerCL) throws SQLException {
java.util.Vector drivers = null;
/*
* When callerCl is null, we should check the application's
* (which is invoking this class indirectly)
* classloader, so that the JDBC driver class outside rt.jar
* can be loaded from here.
*/
synchronized(DriverManager.class) {
// synchronize loading of the correct classloader.
if(callerCL == null) {
callerCL = Thread.currentThread().getContextClassLoader();
}
}
if(url == null) {
throw new SQLException("The url cannot be null", "08001");
}
println("DriverManager.getConnection(\"" + url + "\")");
if (!initialized) {
initialize();
}
synchronized (DriverManager.class){
// use the readcopy of drivers
drivers = readDrivers;
}
// Walk through the loaded drivers attempting to make a connection.
// Remember the first exception that gets raised so we can reraise it.
SQLException reason = null;
for (int i = 0; i < drivers.size(); i++) {
DriverInfo di = (DriverInfo)drivers.elementAt(i);
// If the caller does not have permission to load the driver then
// skip it.
if ( getCallerClass(callerCL, di.driverClassName ) != di.driverClass ) {
println(" skipping: " + di);
continue;
}
try {
println(" trying " + di);
Connection result = di.driver.connect(url, info);
if (result != null) {
// Success!
println("getConnection returning " + di);
return (result);
}
} catch (SQLException ex) {
if (reason == null) {
reason = ex;
}
}
}
// if we got here nobody could connect.
if (reason != null) {
println("getConnection failed: " + reason);
throw reason;
}
println("getConnection: no suitable driver found for "+ url);
throw new SQLException("No suitable driver found for "+ url, "08001");
}
// Class initialization.
static void initialize() {
if (initialized) {
return;
}
initialized = true;
loadInitialDrivers();
println("JDBC DriverManager initialized");
}
/* Prevent the DriverManager class from being instantiated. */
private DriverManager(){}
/* write copy of the drivers vector */
private static java.util.Vector writeDrivers = new java.util.Vector();
/* write copy of the drivers vector */
private static java.util.Vector readDrivers = new java.util.Vector();
private static int loginTimeout = 0;
private static java.io.PrintWriter logWriter = null;
private static java.io.PrintStream logStream = null;
private static boolean initialized = false;
private static Object logSync = new Object();
/* Returns the caller's class loader, or null if none */
private static native ClassLoader getCallerClassLoader();
}
// DriverInfo is a package-private support class.
class DriverInfo {
Driver driver;
Class driverClass;
String driverClassName;
public String toString() {
return ("driver[className=" + driverClassName + "," + driver + "]");
}
}