Initial Checkin

1 files changed, 377 insertions, 0 deletions

diff --git a/java/sql/DriverManager.java b/java/sql/DriverManager.java
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+/*************************************************************************
+/* DriverManager.java -- Manage JDBC drivers
+/*
+/* Copyright (c) 1999 Free Software Foundation, Inc.
+/* Written by Aaron M. Renn (arenn@urbanophile.com)
+/*
+/* This library is free software; you can redistribute it and/or modify
+/* it under the terms of the GNU Library General Public License as published 
+/* by the Free Software Foundation, either version 2 of the License, or
+/* (at your option) any later verion.
+/*
+/* This library 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 Library General Public License for more details.
+/*
+/* You should have received a copy of the GNU Library General Public License
+/* along with this library; if not, write to the Free Software Foundation
+/* Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307 USA
+/*************************************************************************/
+
+package java.sql;
+
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.util.Enumeration;
+import java.util.Properties;
+import java.util.StringTokenizer;
+import java.util.Vector;
+
+/**
+  * This class manages the JDBC drivers in the system. It maintains a
+  * registry of drivers and locates the appropriate driver to handle a
+  * JDBC database URL.
+  * <p>
+  * On startup, <code>DriverManager</code> loads all the managers specified
+  * by the system property <code>jdbc.drivers</code>.  The value of this
+  * property should be a colon separated list of fully qualified driver
+  * class names.  Additional drivers can be loaded at any time by
+  * simply loading the driver class with <code>class.forName(String)</code>.
+  * The driver should automatically register itself in a static 
+  * initializer.
+  * <p>
+  * The methods in this class are all <code>static</code>. This class
+  * cannot be instantiated.
+  *
+  * @author Aaron M. Renn (arenn@urbanophile.com)
+  */
+public class DriverManager 
+{
+
+/*
+ * Class Variables
+ */
+
+/**
+  * This is the log stream for JDBC drivers.
+  */
+private static PrintStream log_stream;
+
+/**
+  * This is the log writer for JDBC drivers.
+  */
+private static PrintWriter log_writer;
+
+/**
+  * This is the login timeout used by JDBC drivers.
+  */
+private static int login_timeout;
+
+/**
+  * This is the list of JDBC drivers that are loaded.
+  */
+private static Vector drivers;
+ // Hmm, seems like we might want to do a Hashtable and lookup by something,
+ // but what would it be?
+
+// Load all drivers on startup
+static
+{
+  drivers = new Vector();
+
+  String driver_string = System.getProperty("jdbc.drivers");
+  if (driver_string != null)
+    {
+      StringTokenizer st = new StringTokenizer(driver_string);
+      while (st.hasMoreTokens())
+        {
+          String driver_classname = st.nextToken();
+
+          try
+            {
+              Class.forName(driver_classname); // The driver registers itself
+            }
+          catch (Exception e) { ; } // Ignore not founds
+        }
+    }
+
+}
+  
+/*************************************************************************/
+
+/*
+ * Class Methods
+ */
+
+/**
+  * This method returns the login timeout in use by JDBC drivers systemwide.
+  *
+  * @return The login timeout.
+  */
+public static int
+getLoginTimeout()
+{
+  return(login_timeout);
+}
+
+/*************************************************************************/
+
+/**
+  * This method set the login timeout used by JDBC drivers.  This is a
+  * system-wide parameter that applies to all drivers.
+  *
+  * @param login_timeout The new login timeout value.
+  */
+public static void
+setLoginTimeout(int login_timeout)
+{
+  DriverManager.login_timeout = login_timeout;
+}
+
+/*************************************************************************/
+
+/**
+  * This method returns the log writer being used by all JDBC drivers.
+  * This method should be used in place of the deprecated
+  * <code>getLogStream</code> method.
+  *
+  * @return The log writer in use by JDBC drivers.
+  */
+public static PrintWriter
+getLogWriter()
+{
+  return(log_writer);
+}
+
+/*************************************************************************/
+
+/**
+  * This method sets the log writer being used by JDBC drivers.  This is a
+  * system-wide parameter that affects all drivers.  Note that since there
+  * is no way to retrieve a <code>PrintStream</code> from a 
+  * <code>PrintWriter</code>, this method cannot set the log stream in
+  * use by JDBC.  Thus any older drivers may not see this setting.
+  *
+  * @param log_writer The new log writer for JDBC.
+  */
+public static void
+setLogWriter(PrintWriter log_writer)
+{
+  DriverManager.log_writer = log_writer;
+}
+
+/*************************************************************************/
+
+/**
+  * This method returns the log stream in use by JDBC.
+  *
+  * @return The log stream in use by JDBC.
+  *
+  * @deprecated Use <code>getLogWriter()</code> instead.
+  */
+public static PrintStream
+getLogStream()
+{
+  return(log_stream);
+}
+
+/*************************************************************************/
+
+/**
+  * This method sets the log stream in use by JDBC.
+  *
+  * @param log_stream The log stream in use by JDBC.
+  *
+  * @deprecated Use <code>setLogWriter</code> instead.
+  */
+public static void
+setLogStream(PrintStream log_stream)
+{
+  DriverManager.log_stream = log_stream;
+}
+
+/*************************************************************************/
+
+/**
+  * This method prints the specified line to the log stream.
+  *
+  * @param str The string to write to the log stream.
+  */
+public static void
+println(String str)
+{
+  if (log_stream != null) // Watch for user not using logging
+    log_stream.println(str);
+}
+
+/*************************************************************************/
+
+/**
+  * This method registers a new driver with the manager.  This is normally
+  * called by the driver itself in a static initializer.
+  *
+  * @param driver The new <code>Driver</code> to add.
+  */
+public static void
+registerDriver(Driver driver)
+{
+  if (!drivers.contains(driver))
+    drivers.addElement(driver);
+}
+
+/*************************************************************************/
+
+/**
+  * This method de-registers a driver from the manager.
+  *
+  * @param driver The <code>Driver</code> to unregister.
+  */
+public static void
+deregisterDriver(Driver driver)
+{
+  if (drivers.contains(driver))
+    drivers.removeElement(driver);
+}
+
+/*************************************************************************/
+
+/**
+  * This method returns a list of all the currently registered JDBC drivers
+  * that were loaded by the current <code>ClassLoader</code>.
+  *
+  * @return An <code>Enumeration</code> of all currently loaded JDBC drivers.
+  */
+public static Enumeration
+getDrivers()
+{
+  Vector v = new Vector();
+  Enumeration e = drivers.elements();
+
+  // Is this right?
+  ClassLoader cl = Thread.currentThread().getContextClassLoader();
+
+  while(e.hasMoreElements())
+    {
+      Object obj = e.nextElement();
+      if (!obj.getClass().getClassLoader().equals(cl))
+        continue;
+
+      v.addElement(obj);
+    } 
+
+  return(v.elements());
+}
+
+/*************************************************************************/
+
+/**
+  * This method returns a driver that can connect to the specified
+  * JDBC URL string.  This will be selected from among drivers loaded
+  * at initialization time and those drivers manually loaded by the
+  * same class loader as the caller.
+  *
+  * @param url The JDBC URL string to find a driver for.
+  *
+  * @return A <code>Driver</code> that can connect to the specified
+  * URL, or <code>null</code> if a suitable driver cannot be found.
+  *
+  * @exception SQLException If an error occurs.
+  */
+public static Driver
+getDriver(String url) throws SQLException
+{
+  // FIXME: Limit driver search to the appropriate subset of loaded drivers.
+
+  Enumeration e = drivers.elements();
+  while(e.hasMoreElements())
+    {
+      Driver d = (Driver)e.nextElement();
+      if (d.acceptsURL(url))
+        return(d);
+    }
+
+  return(null);
+}
+
+/*************************************************************************/
+
+/**
+  * This method attempts to return a connection to the specified
+  * JDBC URL string.
+  *
+  * @param url The JDBC URL string to connect to.
+  *
+  * @return A <code>Connection</code> to that URL.
+  *
+  * @exception SQLException If an error occurs.
+  */
+public static Connection
+getConnection(String url) throws SQLException
+{
+  return(getConnection(url, new Properties()));
+}
+
+/*************************************************************************/
+
+/**
+  * This method attempts to return a connection to the specified
+  * JDBC URL string using the specified username and password.
+  *
+  * @param url The JDBC URL string to connect to.
+  * @param user The username to connect with.
+  * @param password The password to connect with.
+  *
+  * @return A <code>Connection</code> to that URL.
+  *
+  * @exception SQLException If an error occurs.
+  */
+public static Connection
+getConnection(String url, String user, String password) throws SQLException
+{
+  Properties p = new Properties();
+
+  p.setProperty("user", user);
+  p.setProperty("password", password);
+
+  return(getConnection(url, p));
+}
+
+/*************************************************************************/
+
+/**
+  * This method attempts to return a connection to the specified
+  * JDBC URL string using the specified connection properties.
+  *
+  * @param url The JDBC URL string to connect to.
+  * @param properties The connection properties.
+  *
+  * @return A <code>Connection</code> to that URL.
+  *
+  * @exception SQLException If an error occurs.
+  */
+public static Connection
+getConnection(String url, Properties properties) throws SQLException
+{
+  Driver d = getDriver(url);
+  if (d == null)
+    throw new SQLException("Driver not found for URL: " + url);
+
+  return(d.connect(url, properties));
+}
+
+/*************************************************************************/
+
+/*
+ * Constructors
+ */
+
+// Keep bozos from trying to instantiate us.
+private
+DriverManager()
+{
+  ;
+}
+
+} // class DriverManager 
+