Facade Pattern
The Facade Pattern is used to consolidate numerous complicated objects and function calls in a single interface.
UML Example
Code Examples
Java
C++
C# .NET
VB .NET
Open Source Applications
Apache Excalibur
/**
* A facade to the modularized *LoggerManager building system.
* Add methods here to create LoggerManagers to your preference.
*
* @author <a href="mailto:dev@nospamavalon.apache.org">Avalon Development Team</a>
* @version CVS $Revision: 1.3 $ $Date: 2004/03/10 13:54:50 $
* @since 4.0
*/
public class Facade
{
/**
* Assemble a new LoggerManager running on top of LogKit
* configured from a configuration file logging to a supplied
* logger as a fallback.
* Use this method as a sample showing how to assemble your
* own LoggerManager running on top of LogKit flavour.
*/
public static LoggerManager createLogKitConfigurable(
final String prefix, final String switchTo )
{
final org.apache.log.Hierarchy hierarchy = new Hierarchy();
final LoggerManager bare = new LogKitAdapter( hierarchy );
final LoggerManager decorated = applyDecorators( bare, prefix, switchTo );
final LoggerManagerTee tee = new LoggerManagerTee( decorated );
tee.addTee( new LogKitLoggerHelper( hierarchy ) );
tee.addTee( new LogKitConfHelper( hierarchy ) );
tee.makeReadOnly();
return tee;
}
/**
* Assemble LoggerManager for Log4J system configured
* via a configuration file. All the logging errors
* will go to System.err however.
*/
public static LoggerManager createLog4JConfigurable(
final String prefix, final String switchTo )
{
final LoggerManager bare = new Log4JConfAdapter();
final LoggerManager decorated = applyDecorators( bare, prefix, switchTo );
return decorated;
}
private static LoggerManager applyDecorators( LoggerManager target,
final String prefix, final String switchTo )
{
if ( switchTo != null )
{
target = new LogToSelfDecorator( target, switchTo );
}
if ( prefix != null && prefix.length() > 0 )
{
target = new PrefixDecorator( target, prefix );
}
target = new CachingDecorator( target );
return target;
}
}