dlr 01/10/21 13:59:42
Modified: src/java/org/apache/turbine/util/db/adapter DBFactory.java
Log:
Backported some of my clarifications from the jakarta-turbine-torque
module as to what this class actually does and how it works:
Table of "drivers" is actually a table of "adapters" keyed by JDBC
driver name. Updated documentation, variable, and methods names
appropriately.
Revision Changes Path
1.2 +46 -34
jakarta-turbine-2/src/java/org/apache/turbine/util/db/adapter/DBFactory.java
Index: DBFactory.java
===================================================================
RCS file:
/home/cvs/jakarta-turbine-2/src/java/org/apache/turbine/util/db/adapter/DBFactory.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -u -r1.1 -r1.2
--- DBFactory.java 2001/08/16 05:09:50 1.1
+++ DBFactory.java 2001/10/21 20:59:42 1.2
@@ -70,23 +70,28 @@
* @author <a href="mailto:[EMAIL PROTECTED]";>Jon S. Stevens</a>
* @author <a href="mailto:[EMAIL PROTECTED]";>Brett McLaughlin</a>
* @author <a href="mailto:[EMAIL PROTECTED]";>Ralf Stranzenbach</a>
- * @version $Id: DBFactory.java,v 1.1 2001/08/16 05:09:50 jvanzyl Exp $
+ * @author <a href="mailto:[EMAIL PROTECTED]";>Daniel Rall</a>
+ * @version $Id: DBFactory.java,v 1.2 2001/10/21 20:59:42 dlr Exp $
*/
public class DBFactory
{
- // List of registered drivers.
- private static Hashtable drivers = null;
+ /**
+ * A table of <code>Class</code> objects for registered adapters,
+ * keyed by the fully qualified class name of their associated
+ * JDBC driver.
+ */
+ private static Hashtable adapters = null;
// This static code creates the list of possible drivers and adds
- // the "NO DATABASE" adaptor to this list. After all the
+ // the "NO DATABASE" adapter to this list. After all the
// TurbineResources is queried to get a list of JDBC drivers and
// their associated adaptors.
static
{
- drivers = new Hashtable();
+ adapters = new Hashtable();
// Add the null db driver.
- registerDriver("", DBNone.class);
+ registerAdapter("", DBNone.class);
Enumeration adaptors =
TurbineResources.getVector("database.adaptor").elements();
@@ -113,64 +118,71 @@
Log.error(ign2);
}
}
- if ((c != null) && (driver != null))
+ if (c != null && driver != null)
{
- registerDriver(driver, c);
+ registerAdapter(driver, c);
}
}
}
/**
- * Try to register the class of a database driver at the factory.
- * This concept allows for dynamically adding new database drivers
- * using the configuration files instead of changing the codebase.
+ * Registers the <code>Class</code> of a database adapter at the
+ * factory. This concept allows for dynamically adding new
+ * database adapters using the configuration files instead of
+ * changing the codebase.
*
- * @param driver The fully-qualified name of the JDBC driver to create.
- * @param dc The named JDBC driver.
+ * @param driver The fully-qualified class name of the JDBC driver
+ * to associate with an adapter.
+ * @param adapterClass The <code>Class</code> of the database
+ * adapter associated with <code>driver</code>.
*/
- private static void registerDriver(String driver, Class dc)
+ private static void registerAdapter(String driver, Class adapterClass)
{
- if (!drivers.containsKey(driver))
- // Add this new driver class to the list of known drivers.
- drivers.put(driver, dc);
+ if (!adapters.containsKey(driver))
+ {
+ // Add this new adapter class to the list of known adapters.
+ adapters.put(driver, adapterClass);
+ }
}
/**
* Creates an instance of the Turbine database adapter associated with the
* specified JDBC driver.
- *
- * NOTE: This method used to be <code>protected</code>. I'd like to try
- * to get it back that way ASAP. I had to change its access level since
- * it is called by <code>ConnectionPool</code>, and these two
- * classes are no longer in the same package. -Daniel <[EMAIL PROTECTED]>
+
+ /**
+ * Creates a new instance of the Turbine database adapter associated
+ * with the specified JDBC driver.
*
- * @param driver The fully-qualified name of the JDBC driver to create.
- * @return An instance of a Turbine database adapter.
+ * @param driver The fully-qualified name of the JDBC driver to
+ * create a new adapter instance for.
+ * @return An instance of a Turbine database adapter.
*/
public static DB create(String driver)
throws InstantiationException
{
- Class dc = (Class)drivers.get(driver);
+ Class adapterClass = (Class) adapters.get(driver);
- if (dc != null)
+ if (adapterClass != null)
{
try
{
- // Create an instantiation of the driver.
- DB retVal = (DB)dc.newInstance();
- retVal.setJDBCDriver(driver);
- return retVal;
+ DB adapter = (DB) adapterClass.newInstance();
+ adapter.setJDBCDriver(driver);
+ return adapter;
}
catch (IllegalAccessException e)
{
- throw new InstantiationException(
- "Driver " + driver + " not instantiated.");
+ throw new InstantiationException
+ ("Could not instantiate adapter for JDBC driver: " +
+ driver + ": Assure that adapter bytecodes are in your " +
+ "classpath");
}
}
else
{
- throw new InstantiationException(
- "Database type " + driver + " not implemented.");
+ throw new InstantiationException
+ ("Unknown JDBC driver: " + driver + ": Check your " +
+ "configuration file");
}
}
}
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