DPML Notify

[mcconnell AT dpml.net]

Author: mcconnell AT dpml.net
Date: Tue May 10 14:47:13 2005
New Revision: 2495

Added:
   
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerDescriptor.java
      - copied, changed from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerDescriptor.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerRegistry.java
      - copied, changed from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerRegistry.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerDescriptor.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerRegistry.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/images/misc.png
   (contents, props changed)
   
development/main/transit/core/handler/src/main/net/dpml/transit/images/server.png
   (contents, props changed)
   
development/main/transit/core/handler/src/main/net/dpml/transit/images/source.png
   (contents, props changed)
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerControllerPanel.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerPanel.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/GenericTable.java
      - copied, changed from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTable.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/NodeTableModel.java
      - copied, changed from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTableModel.java
Removed:
   
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerDescriptor.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerRegistry.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTable.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTableModel.java
Modified:
   
development/main/transit/core/handler/src/main/net/dpml/transit/SecuredTransitContext.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/Transit.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/artifact/ArtifactURLConnection.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/logging/StandardFormatter.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostPanel.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ResourcePanel.java
   
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/TransitDialog.java
   
development/main/transit/core/handler/src/test/net/dpml/transit/test/LinkTestCase.java
   
development/main/transit/core/handler/src/test/net/dpml/transit/test/OfflineTestCase.java
   
development/main/transit/core/handler/src/test/net/dpml/transit/test/OnlineTestCase.java
Log:
Add support for custom content handler controllers.  This updates introduce a 
initialization phase to the singleton transit instance during which the 
sub-systems established by the SecuredTransitContext may be updated within a 
context within which an initial Transit instance has been established.

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/SecuredTransitContext.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/SecuredTransitContext.java
  (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/SecuredTransitContext.java
  Tue May 10 14:47:13 2005
@@ -21,6 +21,8 @@
 import net.dpml.io.ResourceHelper;
 import net.dpml.lang.NullArgumentException;
 import net.dpml.transit.cache.CacheHandler;
+import net.dpml.transit.content.ContentHandlerRegistry;
+import net.dpml.transit.content.DefaultContentHandlerRegistry;
 import net.dpml.transit.host.ResourceManager;
 import net.dpml.transit.link.FileLinkManager;
 import net.dpml.transit.link.LinkManager;
@@ -28,6 +30,7 @@
 import net.dpml.transit.network.RequestIdentifier;
 import net.dpml.transit.network.TransitAuthenticator;
 import net.dpml.transit.network.TransitAuthenticatorImpl;
+import net.dpml.transit.repository.StandardLoader;
 import net.dpml.transit.util.Util;
 
 import java.io.File;
@@ -36,6 +39,7 @@
 import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.net.MalformedURLException;
+import java.net.URI;
 import java.net.URL;
 import java.net.UnknownHostException;
 import java.util.logging.Logger;
@@ -55,20 +59,6 @@
     // static
     //------------------------------------------------------------------
 
-    // The following static operations is here simply to setup an example 
content 
-    // handler plugin declaration that we can use for testing.  This will be 
-    // removed once a proper installation strategy is established for 
content 
-    // handler plugins.
-    
-    static
-    {
-        Preferences prefs = Preferences.userNodeForPackage( 
SecuredTransitContext.class );
-        Preferences content = prefs.node( "content" );
-        Preferences p = content.node( "part" );
-        p.put( "title", "Part Content Handler" );
-        p.put( "uri", 
"artifact:plugin:dpml/tools/dpml-composition-unit#SNAPSHOT" );
-    }
-
    /**
     * The namespace string for transit related properties.
     */
@@ -144,6 +134,18 @@
     */
     private static final String DEFAULT_REMOTE_AUTHORITY = 
"http://repository.dpml.net";;
 
+   /**
+    * Return the singleton context.
+    * @return the secure context
+    */
+    public static SecuredTransitContext getInstance()
+    {
+        synchronized( SecuredTransitContext.class )
+        {
+            return m_CONTEXT;
+        }
+    }
+
     //------------------------------------------------------------------
     // state
     //------------------------------------------------------------------
@@ -169,19 +171,62 @@
     private URL m_authorativeHost;
 
    /**
-    * Return the singleton context.
-    * @return the secure context
+    * Logging channel.
     */
-    public static SecuredTransitContext getInstance()
+    private Logger m_logger;
+
+   /**
+    * Prefs enabled flag.
+    */
+    private boolean m_prefsEnabled = false;
+
+    //------------------------------------------------------------------
+    // constructors
+    //------------------------------------------------------------------
+
+    /**
+     * Creation of a new secured transit context.
+     * @param authorative the authorative url.
+     * @param props the properties for the secured transit context.
+     * @param handler the cache handler.
+     * @exception TransitException if a context creation error occurs.
+     */
+    private SecuredTransitContext( 
+      boolean flag, URL authorative, ContentHandlerRegistry registry, 
CacheHandler handler, Properties props )
+        throws TransitException
     {
-        synchronized( SecuredTransitContext.class )
+        this( flag, handler, registry );
+        try
         {
-            return m_CONTEXT;
+            setupAuthenticator( props );
         }
+        catch( IOException e )
+        {
+            throw new TransitException( "Unable to read Transit 
configuration at " + authorative, e );
+        }
+    }
+
+    /**
+     * Creation of a new secured transit context using a remote service.
+     * @param handler the cache handler
+     */
+    private SecuredTransitContext( boolean flag, CacheHandler handler, 
ContentHandlerRegistry registry )
+    {
+        m_prefsEnabled = flag;
+        m_authorativeHost = null;
+        m_cacheHandler = handler;
+        m_contentHandlerRegistry = registry;
+
+        m_logger = Logger.getLogger( "transit" );
+
+        // Niclas; Hardcoding the LinkManager for now. When/If pluggable
+        //         LinkManagers becomes a reality, we'll worry about how
+        //         to install them.
+        m_linkManager = new FileLinkManager();
     }
 
     //------------------------------------------------------------------
-    // implementation
+    // SecuredTransitContext 
     //------------------------------------------------------------------
 
    /**
@@ -230,16 +275,15 @@
                     classname = getResourceManagerClassname( props ); // 
using properties
                 }
 
-                Preferences prefs = Preferences.userNodeForPackage( 
SecuredTransitContext.class );
-                Preferences content = prefs.node( "content" );
-                ContentHandlerRegistry registry = new 
ContentHandlerRegistry( logger, content );
+                Preferences prefs = Preferences.userNodeForPackage( 
ContentHandlerRegistry.class );
+                ContentHandlerRegistry registry = new 
DefaultContentHandlerRegistry( logger, prefs );
                 ResourceManager manager = createResourceManager( classname, 
authorative );
                 CacheHandler ch = manager.createCacheHandler();
                 if( logger.isLoggable( Level.FINE ) )
                 {
                    logger.fine( "establish cache: " + 
ch.getClass().getName() );
                 }
-                m_CONTEXT = new SecuredTransitContext( authorative, 
registry, ch, props );
+                m_CONTEXT = new SecuredTransitContext( flag, authorative, 
registry, ch, props );
             }
             catch( Exception e )
             {
@@ -251,6 +295,161 @@
         }
     }
 
+    /**
+     * Return cache handler directory.
+     * @return the cache handler
+     */
+    public CacheHandler getCacheHandler()
+    {
+        return m_cacheHandler;
+    }
+
+    public LinkManager getLinkManager()
+    {
+        return m_linkManager;
+    }
+
+   /**
+    * Return the registry of pluggable content handlers.
+    * @return the content handler registry
+    */
+    public ContentHandlerRegistry getContentHandlerRegistry()
+    {
+        return m_contentHandlerRegistry;
+    }
+
+    /**
+     * Return the authorative host URL.
+     * @return the authorative host url
+     */
+    public URL getAuthorativeHost()
+    {
+        return m_authorativeHost;
+    }
+
+   /**
+    * Initialization of any sub-systems following the establishment of the 
initial
+    * transit system. As a general principal any subsystems that cannot be 
established
+    * for technical reasons (security or permission restrictions, etc.) 
should log 
+    * an appropriate message and fallback to the initial setup thereby 
ensuring that
+    * an operable transit system is available.
+    *
+    * @exception TransitException if an initialization error occurs
+    */
+    protected void initialize() throws TransitException
+    {
+        if( false == m_prefsEnabled )
+        {
+            return;
+        }
+        Preferences prefs = Preferences.userNodeForPackage( 
ContentHandlerRegistry.class );
+        String path = prefs.get( "uri", null );
+        if( null != path )
+        {
+            m_logger.info( "assigning custom content handler registry" );
+            try
+            {
+                URI uri = new URI( path );
+                StandardLoader loader = new StandardLoader();
+                Object[] args = new Object[]{ prefs, m_logger };
+                ClassLoader classloader = Transit.class.getClassLoader();
+                ContentHandlerRegistry registry = (ContentHandlerRegistry) 
loader.getPlugin( classloader, uri, args );
+                m_contentHandlerRegistry = registry;
+                m_logger.info( "registry uri: " + path );
+            }
+            catch( Throwable e )
+            {
+                final String error = 
+                  "Bypassing custom content hander registry assignment due 
to internal error.";
+                m_logger.log( Level.WARNING, error, e );
+            }
+        }
+    }
+
+    //------------------------------------------------------------------
+    // internals 
+    //------------------------------------------------------------------
+
+   /**
+    * Setup the transit authenticator.
+    * @param properties the transit properties
+    * @exception UnknownHostException if a proxy host is declared but is 
unknown
+    */
+    private void setupAuthenticator( Properties properties )
+        throws UnknownHostException
+    {
+        TransitAuthenticator ta = createProxyAuthenticator( properties );
+        if( ta != null )
+        {
+            RequestIdentifier id = createProxyRequestIdentifier( properties 
);
+            DelegatingAuthenticator da = 
DelegatingAuthenticator.getInstance();
+            da.addTransitAuthenticator( ta, id );
+        }
+    }
+
+   /**
+    * Creation of a new transit authenticator.
+    * @param properties the transit properties
+    * @return the transit authenticator
+    */
+    private TransitAuthenticator createProxyAuthenticator( Properties 
properties )
+    {
+        String username = Util.getProperty( properties, PROXY_USERNAME_KEY, 
null );
+        String password = Util.getProperty( properties, PROXY_PASSWORD_KEY, 
null );
+        if( null == username )
+        {
+            return null;
+        }
+        return new TransitAuthenticatorImpl( username, password );
+    }
+
+   /**
+    * Creation of a new request identifier.
+    * @param properties the transit properties
+    * @return the request identifier
+    * @exception UnknownHostException if a proxy host is declared but is 
unknown
+    * @exception IllegalArgumentException if a proxy host is declared and
+    *   either the proxy scheme or proxy prompt property values are undefined
+    */
+    private RequestIdentifier createProxyRequestIdentifier( Properties 
properties )
+        throws UnknownHostException, IllegalArgumentException
+    {
+        String proxy = Util.getProperty( properties, PROXY_HOST_KEY, null );
+        if( null == proxy )
+        {
+            return null;
+        }
+
+        String protocol = Util.getProperty( properties, PROXY_PROTOCOL_KEY, 
"http" );
+        String scheme = Util.getProperty( properties, PROXY_SCHEME_KEY, null 
);
+        if( scheme == null )
+        {
+            throw new IllegalArgumentException( "Missing " + 
PROXY_SCHEME_KEY + " in properties." );
+        }
+        String prompt = Util.getProperty( properties, PROXY_PROMPT_KEY, null 
);
+        if( prompt == null )
+        {
+            throw new IllegalArgumentException( "Missing " + 
PROXY_PROMPT_KEY + " in properties." );
+        }
+
+        String portText = Util.getProperty( properties, PROXY_PORT_KEY, "0" 
);
+        int port = Integer.parseInt( portText );
+        Properties system = System.getProperties();
+        system.put( "http.proxyHost", proxy );
+        system.put( "http.proxyPort", "" + port );
+        String excludes = Util.getProperty( properties, PROXY_EXCLUDES_KEY, 
null );
+        if( null != excludes )
+        {
+            system.put( "http.nonProxyHosts", excludes );
+        }
+        RequestIdentifier id = new RequestIdentifier( proxy, port, protocol, 
scheme, prompt );
+        return id;
+    }
+
+    //------------------------------------------------------------------
+    // internal static utilities
+    //------------------------------------------------------------------
+
    /**
     * Create the resource manager that will be responsible for the 
establishment
     * of the transit cache handler. The class implementating the resource 
manager
@@ -337,43 +536,6 @@
               ResourceManager.TRANSIT_RESOURCE_MANAGER_CLASSNAME ) );
     }
 
-    /**
-     * Creation of a new secured transit context.
-     * @param authorative the authorative url.
-     * @param props the properties for the secured transit context.
-     * @param handler the cache handler.
-     * @exception TransitException if a context creation error occurs.
-     */
-    private SecuredTransitContext( URL authorative, ContentHandlerRegistry 
registry, CacheHandler handler, Properties props )
-        throws TransitException
-    {
-        this( handler, registry );
-        try
-        {
-            setupAuthenticator( props );
-        }
-        catch( IOException e )
-        {
-            throw new TransitException( "Unable to read Transit 
configuration at " + authorative, e );
-        }
-    }
-
-    /**
-     * Creation of a new secured transit context using a remote service.
-     * @param handler the cache handler
-     */
-    private SecuredTransitContext( CacheHandler handler, 
ContentHandlerRegistry registry )
-    {
-        m_authorativeHost = null;
-        m_cacheHandler = handler;
-        m_contentHandlerRegistry = registry;
-
-        // Niclas; Hardcoding the LinkManager for now. When/If pluggable
-        //         LinkManagers becomes a reality, we'll worry about how
-        //         to install them.
-        m_linkManager = new FileLinkManager();
-    }
-
     private static Properties getTransitProperties( URL authorative ) throws 
IOException
     {
         try
@@ -389,38 +551,6 @@
         }
     }
 
-    /**
-     * Return cache handler directory.
-     * @return the cache handler
-     */
-    public CacheHandler getCacheHandler()
-    {
-        return m_cacheHandler;
-    }
-
-    public LinkManager getLinkManager()
-    {
-        return m_linkManager;
-    }
-
-   /**
-    * Return the registry of pluggable content handlers.
-    * @return the content handler registry
-    */
-    public ContentHandlerRegistry getContentHandlerRegistry()
-    {
-        return m_contentHandlerRegistry;
-    }
-
-    /**
-     * Return the authorative host URL.
-     * @return the authorative host url
-     */
-    public URL getAuthorativeHost()
-    {
-        return m_authorativeHost;
-    }
-
    /**
     * Resolve the authorative url.  The implementation will check for a
     * system property named "dpml.transit.authority.file".  If the value
@@ -641,79 +771,4 @@
         }
     }
 
-   /**
-    * Setup the transit authenticator.
-    * @param properties the transit properties
-    * @exception UnknownHostException if a proxy host is declared but is 
unknown
-    */
-    private void setupAuthenticator( Properties properties )
-        throws UnknownHostException
-    {
-        TransitAuthenticator ta = createProxyAuthenticator( properties );
-        if( ta != null )
-        {
-            RequestIdentifier id = createProxyRequestIdentifier( properties 
);
-            DelegatingAuthenticator da = 
DelegatingAuthenticator.getInstance();
-            da.addTransitAuthenticator( ta, id );
-        }
-    }
-
-   /**
-    * Creation of a new transit authenticator.
-    * @param properties the transit properties
-    * @return the transit authenticator
-    */
-    private TransitAuthenticator createProxyAuthenticator( Properties 
properties )
-    {
-        String username = Util.getProperty( properties, PROXY_USERNAME_KEY, 
null );
-        String password = Util.getProperty( properties, PROXY_PASSWORD_KEY, 
null );
-        if( null == username )
-        {
-            return null;
-        }
-        return new TransitAuthenticatorImpl( username, password );
-    }
-
-   /**
-    * Creation of a new request identifier.
-    * @param properties the transit properties
-    * @return the request identifier
-    * @exception UnknownHostException if a proxy host is declared but is 
unknown
-    * @exception IllegalArgumentException if a proxy host is declared and
-    *   either the proxy scheme or proxy prompt property values are undefined
-    */
-    private RequestIdentifier createProxyRequestIdentifier( Properties 
properties )
-        throws UnknownHostException, IllegalArgumentException
-    {
-        String proxy = Util.getProperty( properties, PROXY_HOST_KEY, null );
-        if( null == proxy )
-        {
-            return null;
-        }
-
-        String protocol = Util.getProperty( properties, PROXY_PROTOCOL_KEY, 
"http" );
-        String scheme = Util.getProperty( properties, PROXY_SCHEME_KEY, null 
);
-        if( scheme == null )
-        {
-            throw new IllegalArgumentException( "Missing " + 
PROXY_SCHEME_KEY + " in properties." );
-        }
-        String prompt = Util.getProperty( properties, PROXY_PROMPT_KEY, null 
);
-        if( prompt == null )
-        {
-            throw new IllegalArgumentException( "Missing " + 
PROXY_PROMPT_KEY + " in properties." );
-        }
-
-        String portText = Util.getProperty( properties, PROXY_PORT_KEY, "0" 
);
-        int port = Integer.parseInt( portText );
-        Properties system = System.getProperties();
-        system.put( "http.proxyHost", proxy );
-        system.put( "http.proxyPort", "" + port );
-        String excludes = Util.getProperty( properties, PROXY_EXCLUDES_KEY, 
null );
-        if( null != excludes )
-        {
-            system.put( "http.nonProxyHosts", excludes );
-        }
-        RequestIdentifier id = new RequestIdentifier( proxy, port, protocol, 
scheme, prompt );
-        return id;
-    }
 }

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/Transit.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/Transit.java  
      (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/Transit.java  
      Tue May 10 14:47:13 2005
@@ -1,5 +1,5 @@
 /*
- * Copyright 2004 Stephen McConnell.
+ * Copyright 2004-2005 Stephen McConnell.
  * Copyright 2004-2005 Niclas Hedhman.
  *
  * Licensed  under the  Apache License,  Version 2.0  (the "License");
@@ -45,6 +45,10 @@
  */
 public final class Transit
 {
+    //------------------------------------------------------------------
+    // static 
+    //------------------------------------------------------------------
+
    /**
     * DPML home key.
     */
@@ -76,39 +80,6 @@
     public static final String SYSTEM_SYMBOL =       "DPML_SYSTEM";
 
    /**
-    * Singleton transit instance.
-    */
-    private static Transit m_INSTANCE;
-
-   /**
-    * Repository established by transit.
-    */
-    private Repository m_repository;
-
-   /**
-    * Singleton repository monitor router.
-    */
-    private RepositoryMonitorRouter m_repositoryMonitor;
-
-   /**
-    * Singleton cache monitor router.
-    */
-    private CacheMonitorRouter m_cacheMonitor;
-
-   /**
-    * Singleton network monitor router.
-    */
-    private NetworkMonitorRouter m_networkMonitor;
-
-   /**
-    * PrintWriter where operations troubleshooting messages
-    * can be written to.
-    */
-    private PrintWriter m_logWriter;
-
-    private SecuredTransitContext m_context;
-
-   /**
     * The DPML home directory established via assesment of the the 
${dpml.home}
     * system property and the DPML_HOME environment variable.  If neither are
     * defined the behaviour is platform specific.  If the os is Windows,
@@ -170,11 +141,50 @@
             if( m_INSTANCE == null )
             {
                 m_INSTANCE = new Transit();
+
+                // before returning from this method we need to give the 
transit
+                // subsystems a chance to complete initialization actions 
that 
+                // are themselves dependent on an establish Transit instance
+
+                m_INSTANCE.getTransitContext().initialize();
             }
             return m_INSTANCE;
         }
     }
 
+    //------------------------------------------------------------------
+    // state 
+    //------------------------------------------------------------------
+
+   /**
+    * Repository established by transit.
+    */
+    private Repository m_repository;
+
+   /**
+    * Singleton repository monitor router.
+    */
+    private RepositoryMonitorRouter m_repositoryMonitor;
+
+   /**
+    * Singleton cache monitor router.
+    */
+    private CacheMonitorRouter m_cacheMonitor;
+
+   /**
+    * Singleton network monitor router.
+    */
+    private NetworkMonitorRouter m_networkMonitor;
+
+   /**
+    * PrintWriter where operations troubleshooting messages
+    * can be written to.
+    */
+    private PrintWriter m_logWriter;
+
+    private SecuredTransitContext m_context;
+
+
     SecuredTransitContext getTransitContext()
     {
         return m_context;
@@ -508,4 +518,13 @@
             "net.dpml.transit.logging.ConfigurationHandler" ) );
     }
 
+    //------------------------------------------------------------------
+    // static internal 
+    //------------------------------------------------------------------
+
+   /**
+    * Singleton transit instance.
+    */
+    private static Transit m_INSTANCE;
+
 }

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/artifact/ArtifactURLConnection.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/artifact/ArtifactURLConnection.java
 (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/artifact/ArtifactURLConnection.java
 Tue May 10 14:47:13 2005
@@ -33,12 +33,14 @@
 import net.dpml.transit.Transit;
 import net.dpml.transit.TransitException;
 import net.dpml.transit.SecuredTransitContext;
-import net.dpml.transit.ContentHandlerRegistry;
+import net.dpml.transit.content.ContentHandlerRegistry;
 import net.dpml.transit.cache.CacheHandler;
 import net.dpml.transit.layout.ClassicResolver;
 import net.dpml.transit.layout.LocationResolver;
 import net.dpml.transit.util.MimeTypeHandler;
 import net.dpml.transit.util.StreamUtils;
+import net.dpml.transit.repository.StandardLoader;
+import net.dpml.transit.repository.Plugin;
 
 /**
  * Artifact URL protocol connection processor.
@@ -86,6 +88,9 @@
         throws NullPointerException, IOException
     {
         super( url );
+
+        Transit.getInstance(); // make sure Transit is initialized
+
         m_context = context;
         m_reference = getReference( url );
 
@@ -194,12 +199,46 @@
 
         String type = m_artifact.getType();
         ContentHandlerRegistry registry = 
m_context.getContentHandlerRegistry();
-        ContentHandler handler = registry.getContentHandler( getURL(), type 
);
+        ContentHandler handler = registry.getContentHandler( type );
         if( null != handler )
         {
             return handler.getContent( this, classes );
         }
 
+        // 
+        // if the type is a plugin then hande this directly
+        //
+
+        if( "plugin".equals( type ) )
+        { 
+            StandardLoader loader = new StandardLoader();
+            ClassLoader classloader = 
Thread.currentThread().getContextClassLoader();
+            URI uri = m_artifact.toURI();
+            if( classes.length == 0 )
+            { 
+                return loader.getPlugin( classloader, uri, new Object[0] );
+            }
+            else
+            {
+                for( int i=0; i<classes.length; i++ )
+                {
+                    Class c = classes[i];
+                    if( ClassLoader.class.equals( c ) )
+                    {
+                        return loader.getPluginClassLoader( classloader, uri 
);
+                    }
+                    else if( Class.class.equals( c ) )
+                    {
+                        return loader.getPluginClass( classloader, uri );
+                    }
+                    else if( Plugin.class.equals( c ) )
+                    {
+                        return loader.getPluginDescriptor( uri );
+                    }
+                }
+            }
+        }
+
         //
         // otherwise fallback on the default jvm content handling
         //

Copied: 
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerDescriptor.java
 (from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerDescriptor.java)
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerDescriptor.java
       (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerDescriptor.java
       Tue May 10 14:47:13 2005
@@ -1,5 +1,6 @@
 /*
- * Copyright 2004 Niclas Hedhman
+ * Copyright 2005 Stephen McConnell
+ *
  * 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
@@ -15,142 +16,18 @@
  * limitations under the License.
  */
 
-package net.dpml.transit;
+package net.dpml.transit.content;
 
 import java.net.URI;
-import java.net.URISyntaxException;
-import java.util.prefs.PreferenceChangeListener;
-import java.util.prefs.PreferenceChangeEvent;
-import java.util.prefs.Preferences;
-import java.util.logging.Logger;
-import java.util.logging.Level;
 
 /**
- * A description of a pluggable content handler.  This class wraps an 
underlying
- * preference node that describes a content handler plugin.  It exposes 
operations 
- * through which the plugin name and URI can be retrieved without directly 
accessing
- * the underlying Preferences instance.
+ * A description of a pluggable content handler. 
  */
-public class ContentHandlerDescriptor implements PreferenceChangeListener
+public interface ContentHandlerDescriptor
 {
-    // 
------------------------------------------------------------------------
-    // state
-    // 
------------------------------------------------------------------------
-
-    private Preferences m_preferences;
-
-    private String m_type;
-
-    private String m_title;
-
-    private URI m_uri;
-
-    private Logger m_logger;
-
-    // 
------------------------------------------------------------------------
-    // constructor
-    // 
------------------------------------------------------------------------
-
-   /**
-    * A description of a pluggable part handler including the part handler 
title
-    * and a uri referencing a plugin that is castable to a ContentHandler 
instance.
-    *
-    * @param logger an internal logging channel
-    * @param prefs the preferences node containing part handler description
-    */
-    public ContentHandlerDescriptor( Logger logger, Preferences prefs )
-    {
-        m_logger = logger;
-        m_preferences = prefs;
-        prefs.addPreferenceChangeListener( this );
-        m_type = prefs.name();
-        m_title = prefs.get( "title", m_type );
-        String path = prefs.get( "uri", null );
-        m_uri = setURI( path );
-    }
-
-    // 
------------------------------------------------------------------------
-    // PreferencesChangeListener
-    // 
------------------------------------------------------------------------
-
-   /**
-    * Listen to changes in the preferences object that defines this 
descriptor
-    * and reflect the changes in the state of the descriptor class.
-    * 
-    * @param event the preference change event
-    */
-    public void preferenceChange( PreferenceChangeEvent event )
-    {
-        String key = event.getKey();
-        String value = event.getNewValue();
-        Preferences prefs = event.getNode();
-        if( "title".equals( key ) )
-        {
-            m_title = value;
-        }
-        else if( "uri".equals( key ) )
-        {
-            m_uri = setURI( value );
-        }
-        else
-        {
-            final String warning = 
-              "A content handler plugin description preference node change 
event references an unrecognized key."
-              + "\nPreference Node: " + m_preferences
-              + "\nKey: " + key;
-            m_logger.log( Level.SEVERE, warning );
-        }
-    }
-
-    // 
------------------------------------------------------------------------
-    // ContenthandlerDescriptor
-    // 
------------------------------------------------------------------------
-
-    public String getContentType()
-    {
-        return m_type;
-    }
-
-    public String getPluginTitle()
-    {
-        return m_title;
-    }
-
-    public URI getPluginURI()
-    {
-        return m_uri;
-    }
-
-    // 
------------------------------------------------------------------------
-    // internals
-    // 
------------------------------------------------------------------------
+    public String getContentType();
 
-    protected void dispose()
-    {
-        m_preferences.removePreferenceChangeListener( this );
-    }
+    public String getPluginTitle();
 
-    private URI setURI( String path )
-    { 
-        if( null == path ) 
-        {
-            return null;
-        }
-        else
-        {
-            try
-            {
-                return new URI( path );
-            }
-            catch( URISyntaxException e )
-            {
-                final String error = 
-                  "A content handler plugin description preference node 
contains an invalid uri attribute."
-                  + "\nPreference Node: " + m_preferences
-                  + "\nURI Value: " + path;
-                m_logger.log( Level.SEVERE, error, e );
-                return null;
-            }
-        }
-    }
+    public URI getPluginURI();
 }

Copied: 
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerRegistry.java
 (from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerRegistry.java)
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/ContentHandlerRegistry.java
 (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/content/ContentHandlerRegistry.java
 Tue May 10 14:47:13 2005
@@ -1,5 +1,6 @@
 /*
- * Copyright 2004 Niclas Hedhman
+ * Copyright 2005 Stephen McConnell
+ *
  * 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
@@ -15,7 +16,7 @@
  * limitations under the License.
  */
 
-package net.dpml.transit;
+package net.dpml.transit.content;
 
 import java.io.IOException;
 import java.net.URI;
@@ -33,217 +34,22 @@
 
 import net.dpml.io.CascadingIOException;
 
+import net.dpml.transit.TransitException;
 import net.dpml.transit.repository.StandardLoader;
 
 /**
- * A registry of descriptions of plugable content handlers.  This 
implementation
- * maps user defined preferences to instance of ContentHandlerDescriptor.
+ * A interface supporting access to pluggable content handlers. An 
implementation
+ * may request a Logger and Preferences node as optional constructor 
arguments.
  */
-public class ContentHandlerRegistry implements NodeChangeListener
+public interface ContentHandlerRegistry
 {
-    // 
------------------------------------------------------------------------
-    // state
-    // 
------------------------------------------------------------------------
-
-    private final Map m_descriptors = new Hashtable();
-
-    private final Preferences m_preferences;
-
-    private Logger m_logger;
-
-    private final Map m_links = new WeakHashMap();
-
-    // 
------------------------------------------------------------------------
-    // constructor
-    // 
------------------------------------------------------------------------
-
-   /**
-    * Responsible for the establishment of a map containing keys that 
correspond to 
-    * artifact types, and values that correspond to the description of a 
-    * content type handler plugins.
-    */
-    public ContentHandlerRegistry( Logger logger, Preferences prefs ) throws 
BackingStoreException
-    {
-        m_logger = logger;
-        m_preferences = prefs;
-        synchronized( m_descriptors )
-        {
-            prefs.addNodeChangeListener( this );
-            String[] names = prefs.childrenNames();
-            for( int i=0; i<names.length; i++ )
-            {
-                String name = names[i];
-                Preferences p = prefs.node( name );
-                addContentHandlerDescriptor( p );
-            }
-        }
-    }
-
-    // 
------------------------------------------------------------------------
-    // ContentHandlerRegistry
-    // 
------------------------------------------------------------------------
-
-    public ContentHandler getContentHandler( final URL url, final String 
type ) throws IOException
-    {
-        URI uri = getContentHandlerDescriptorURI( type );
-        if( null == uri )
-        {
-            return null;
-        }
-        else
-        {
-            ContentHandler handler = (ContentHandler) m_links.get( uri );
-            if( null != handler )
-            {
-                return handler;
-            }
-
-            try
-            {
-                m_logger.info( "loading content handler for: " + type );
-                StandardLoader loader = new StandardLoader();
-                ClassLoader classloader = 
Thread.currentThread().getContextClassLoader();
-                Object plugin = loader.getPlugin( classloader, uri, new 
Object[0] );
-                if( plugin instanceof ContentHandler )
-                {
-                    handler = (ContentHandler) plugin;
-                    m_links.put( uri, handler );
-                    //m_links.put( url, handler );
-                    return handler;
-                }
-                else
-                {
-                    final String error = 
-                      "Content handler plugin uri does not resolve to a 
java.net.ContentHandler."
-                      + "\nHandler URI: " + uri 
-                      + "\nHandler Class: " + plugin.getClass().getName();
-                    throw new TransitException( error );
-                }
-            }
-            catch( Exception e )
-            {
-                final String error = 
-                  "Unable to load a content handler plugin.";
-                throw new CascadingIOException( error, e );
-            }
-        }
-    }
-
-    // 
------------------------------------------------------------------------
-    // NodeChangeListener (listens to host prefs addition and removal)
-    // 
------------------------------------------------------------------------
-
    /**
-    * Handle the addition of a content handler mapping.
+    * Return a content handler capable for supporting the supplied type. If
+    * the a handler is available the handler is returned otherwise the 
returned
+    * value is null.
     *
-    * @param event the node addition event
-    */
-    public void childAdded( NodeChangeEvent event )
-    {
-        Preferences prefs = event.getChild();
-        addContentHandlerDescriptor( prefs );
-    }
-
-    public void childRemoved( NodeChangeEvent event )
-    {
-        Preferences prefs = event.getChild();
-        removeContentHandlerDescriptor( prefs );
-    }
-
-    // 
------------------------------------------------------------------------
-    // internals
-    // 
------------------------------------------------------------------------
-
-    private URI getContentHandlerDescriptorURI( final String type )
-    {
-        ContentHandlerDescriptor descriptor = getContentHandlerDescriptor( 
type );
-        if( null == descriptor )
-        {
-            return null;
-        }
-        else
-        {
-            return descriptor.getPluginURI();
-        }
-    }
-
-    public ContentHandlerDescriptor getContentHandlerDescriptor( final 
String type )
-    { 
-        if( null == type )
-        {
-            throw new NullPointerException( "type" );
-        }
-        synchronized( m_descriptors )
-        {
-            ContentHandlerDescriptor descriptor = (ContentHandlerDescriptor) 
m_descriptors.get( type );
-            if( null == descriptor )
-            {
-                return null;
-            } 
-            else if( null == descriptor.getPluginURI() )
-            {
-                return null;
-            }
-            else
-            {
-                return descriptor;
-            }
-        }
-    }
-
-   /**
-    * Add a description of a content handler based on a supplied 
-    * prefernces object. The name of the preferences object 
-    * corresponds to an artifact type.  Request for the resolution 
-    * of URL content may be resolved by locating a content handler 
-    * plugin for the type exposed by the URL.
-    */
-    private void addContentHandlerDescriptor( ContentHandlerDescriptor 
descriptor )
-    {
-        String type = descriptor.getContentType();
-        if( m_descriptors.containsKey( type ) )
-        {
-            final String error = 
-              "Duplicate content handler descriptor type."
-              + "\nContentHandlerDescriptor: " + descriptor 
-              + "\nContent Type: " + type;
-            throw new IllegalStateException( error );
-        }
-        else
-        {
-            m_logger.fine( "registering '" + type + "' content handler" );
-            m_descriptors.put( type, descriptor );
-        }
-    }
-
-   /**
-    * Add a description of a content handler based on a supplied 
-    * prefernces object. The name of the preferences object 
-    * corresponds to an artifact type.  Request for the resolution 
-    * of URL content may be resolved by locating a content handler 
-    * plugin for the type exposed by the URL.
-    */
-    private void addContentHandlerDescriptor( Preferences prefs )
-    {
-        ContentHandlerDescriptor descriptor = new ContentHandlerDescriptor( 
m_logger, prefs );
-        addContentHandlerDescriptor( descriptor );
-    }
-
-   /**
-    * Remove a content handler descriptor.
-    * @param prefs the preferences node
+    * @param the artifact type
+    * @return the content handler or null if not available
     */
-    private void removeContentHandlerDescriptor( Preferences prefs )
-    {
-        synchronized( m_descriptors )
-        {
-            String type = prefs.name();
-            ContentHandlerDescriptor descriptor = 
getContentHandlerDescriptor( type );
-            if( descriptor != null )
-            {
-                m_descriptors.remove( type );
-                descriptor.dispose();
-            }
-        }
-    }
+    ContentHandler getContentHandler( final String type ) throws IOException;
 }

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerDescriptor.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerDescriptor.java
        Tue May 10 14:47:13 2005
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2005 Stephen McConnell
+ *
+ * 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 net.dpml.transit.content;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.prefs.PreferenceChangeListener;
+import java.util.prefs.PreferenceChangeEvent;
+import java.util.prefs.Preferences;
+import java.util.logging.Logger;
+import java.util.logging.Level;
+
+/**
+ * A description of a pluggable content handler.  This class wraps an 
underlying
+ * preference node that describes a content handler plugin.  It exposes 
operations 
+ * through which the plugin name and URI can be retrieved without directly 
accessing
+ * the underlying Preferences instance.
+ */
+public class DefaultContentHandlerDescriptor implements 
ContentHandlerDescriptor, PreferenceChangeListener
+{
+    // 
------------------------------------------------------------------------
+    // state
+    // 
------------------------------------------------------------------------
+
+    private Preferences m_preferences;
+
+    private String m_type;
+
+    private String m_title;
+
+    private URI m_uri;
+
+    private Logger m_logger;
+
+    // 
------------------------------------------------------------------------
+    // constructor
+    // 
------------------------------------------------------------------------
+
+   /**
+    * A description of a pluggable part handler including the part handler 
title
+    * and a uri referencing a plugin that is castable to a ContentHandler 
instance.
+    *
+    * @param logger an internal logging channel
+    * @param prefs the preferences node containing part handler description
+    */
+    public DefaultContentHandlerDescriptor( Logger logger, Preferences prefs 
)
+    {
+        m_logger = logger;
+        m_preferences = prefs;
+        prefs.addPreferenceChangeListener( this );
+        m_type = prefs.name();
+        m_title = prefs.get( "title", m_type );
+        String path = prefs.get( "uri", null );
+        m_uri = setURI( path );
+    }
+
+    // 
------------------------------------------------------------------------
+    // PreferencesChangeListener
+    // 
------------------------------------------------------------------------
+
+   /**
+    * Listen to changes in the preferences object that defines this 
descriptor
+    * and reflect the changes in the state of the descriptor class.
+    * 
+    * @param event the preference change event
+    */
+    public void preferenceChange( PreferenceChangeEvent event )
+    {
+        String key = event.getKey();
+        String value = event.getNewValue();
+        Preferences prefs = event.getNode();
+        if( "title".equals( key ) )
+        {
+            m_title = value;
+        }
+        else if( "uri".equals( key ) )
+        {
+            m_uri = setURI( value );
+        }
+        else
+        {
+            final String warning = 
+              "A content handler plugin description preference node change 
event references an unrecognized key."
+              + "\nPreference Node: " + m_preferences
+              + "\nKey: " + key;
+            m_logger.log( Level.SEVERE, warning );
+        }
+    }
+
+    // 
------------------------------------------------------------------------
+    // ContentHandlerDescriptor
+    // 
------------------------------------------------------------------------
+
+    public String getContentType()
+    {
+        return m_type;
+    }
+
+    public String getPluginTitle()
+    {
+        return m_title;
+    }
+
+    public URI getPluginURI()
+    {
+        return m_uri;
+    }
+
+    // 
------------------------------------------------------------------------
+    // internals
+    // 
------------------------------------------------------------------------
+
+    protected void dispose()
+    {
+        m_preferences.removePreferenceChangeListener( this );
+    }
+
+    private URI setURI( String path )
+    { 
+        if( null == path ) 
+        {
+            return null;
+        }
+        else
+        {
+            try
+            {
+                return new URI( path );
+            }
+            catch( URISyntaxException e )
+            {
+                final String error = 
+                  "A content handler plugin description preference node 
contains an invalid uri attribute."
+                  + "\nPreference Node: " + m_preferences
+                  + "\nURI Value: " + path;
+                m_logger.log( Level.SEVERE, error, e );
+                return null;
+            }
+        }
+    }
+}

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerRegistry.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/content/DefaultContentHandlerRegistry.java
  Tue May 10 14:47:13 2005
@@ -0,0 +1,273 @@
+/*
+ * Copyright 2005 Stephen McConnell
+ *
+ * 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 net.dpml.transit.content;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URL;
+import java.net.URISyntaxException;
+import java.net.ContentHandler;
+import java.util.Hashtable;
+import java.util.Map;
+import java.util.WeakHashMap;
+import java.util.prefs.Preferences;
+import java.util.prefs.NodeChangeListener;
+import java.util.prefs.NodeChangeEvent;
+import java.util.prefs.BackingStoreException;
+import java.util.logging.Logger;
+
+import net.dpml.io.CascadingIOException;
+
+import net.dpml.transit.TransitException;
+import net.dpml.transit.repository.StandardLoader;
+
+/**
+ * A registry of descriptions of plugable content handlers.  This 
implementation
+ * maps user defined preferences to instance of ContentHandlerDescriptor.
+ */
+public class DefaultContentHandlerRegistry implements 
ContentHandlerRegistry, NodeChangeListener
+{
+    // 
------------------------------------------------------------------------
+    // static
+    // 
------------------------------------------------------------------------
+
+    // The following static operations is here simply to setup an example 
content 
+    // handler plugin declaration that we can use for testing.  This will be 
+    // removed once a proper installation strategy is established for 
content 
+    // handler plugins.
+    
+    static
+    {
+        Preferences prefs = Preferences.userNodeForPackage( 
ContentHandlerRegistry.class );
+        Preferences p = prefs.node( "part" );
+        p.put( "title", "Part Content Handler" );
+        p.put( "uri", 
"artifact:plugin:dpml/tools/dpml-composition-unit#SNAPSHOT" );
+    }
+
+    // 
------------------------------------------------------------------------
+    // state
+    // 
------------------------------------------------------------------------
+
+    private final Map m_descriptors = new Hashtable();
+
+    private final Preferences m_preferences;
+
+    private Logger m_logger;
+
+    private final Map m_links = new WeakHashMap();
+
+    // 
------------------------------------------------------------------------
+    // constructor
+    // 
------------------------------------------------------------------------
+
+   /**
+    * Responsible for the establishment of a map containing keys that 
correspond to 
+    * artifact types, and values that correspond to the description of a 
+    * content type handler plugins.
+    */
+    public DefaultContentHandlerRegistry( Logger logger, Preferences prefs ) 
throws BackingStoreException
+    {
+        m_logger = logger;
+        m_preferences = prefs;
+        synchronized( m_descriptors )
+        {
+            prefs.addNodeChangeListener( this );
+            String[] names = prefs.childrenNames();
+            for( int i=0; i<names.length; i++ )
+            {
+                String name = names[i];
+                Preferences p = prefs.node( name );
+                addContentHandlerDescriptor( p );
+            }
+        }
+    }
+
+    // 
------------------------------------------------------------------------
+    // ContentHandlerRegistry
+    // 
------------------------------------------------------------------------
+
+    public ContentHandler getContentHandler( final String type ) throws 
IOException
+    {
+        URI uri = getContentHandlerDescriptorURI( type );
+        if( null == uri )
+        {
+            return null;
+        }
+        else
+        {
+            ContentHandler handler = (ContentHandler) m_links.get( uri );
+            if( null != handler )
+            {
+                return handler;
+            }
+
+            try
+            {
+                m_logger.info( "loading content handler for: " + type );
+                StandardLoader loader = new StandardLoader();
+                ClassLoader classloader = 
Thread.currentThread().getContextClassLoader();
+                Object plugin = loader.getPlugin( classloader, uri, new 
Object[0] );
+                if( plugin instanceof ContentHandler )
+                {
+                    handler = (ContentHandler) plugin;
+                    m_links.put( uri, handler );
+                    return handler;
+                }
+                else
+                {
+                    final String error = 
+                      "Content handler plugin uri does not resolve to a 
java.net.ContentHandler."
+                      + "\nHandler URI: " + uri 
+                      + "\nHandler Class: " + plugin.getClass().getName();
+                    throw new TransitException( error );
+                }
+            }
+            catch( Exception e )
+            {
+                final String error = 
+                  "Unable to load a content handler plugin.";
+                throw new CascadingIOException( error, e );
+            }
+        }
+    }
+
+    // 
------------------------------------------------------------------------
+    // NodeChangeListener (listens to host prefs addition and removal)
+    // 
------------------------------------------------------------------------
+
+   /**
+    * Handle the addition of a content handler mapping.
+    *
+    * @param event the node addition event
+    */
+    public void childAdded( NodeChangeEvent event )
+    {
+        Preferences prefs = event.getChild();
+        addContentHandlerDescriptor( prefs );
+    }
+
+    public void childRemoved( NodeChangeEvent event )
+    {
+        Preferences prefs = event.getChild();
+        removeContentHandlerDescriptor( prefs );
+    }
+
+    // 
------------------------------------------------------------------------
+    // internals
+    // 
------------------------------------------------------------------------
+
+    private URI getContentHandlerDescriptorURI( final String type )
+    {
+        ContentHandlerDescriptor descriptor = getContentHandlerDescriptor( 
type );
+        if( null == descriptor )
+        {
+            return null;
+        }
+        else
+        {
+            return descriptor.getPluginURI();
+        }
+    }
+
+    public ContentHandlerDescriptor getContentHandlerDescriptor( final 
String type )
+    { 
+        if( null == type )
+        {
+            throw new NullPointerException( "type" );
+        }
+        synchronized( m_descriptors )
+        {
+            ContentHandlerDescriptor descriptor = (ContentHandlerDescriptor) 
m_descriptors.get( type );
+            if( null == descriptor )
+            {
+                return null;
+            } 
+            else if( null == descriptor.getPluginURI() )
+            {
+                return null;
+            }
+            else
+            {
+                return descriptor;
+            }
+        }
+    }
+
+   /**
+    * Add a description of a content handler based on a supplied 
+    * prefernces object. The name of the preferences object 
+    * corresponds to an artifact type.  Request for the resolution 
+    * of URL content may be resolved by locating a content handler 
+    * plugin for the type exposed by the URL.
+    */
+    protected void addContentHandlerDescriptor( ContentHandlerDescriptor 
descriptor )
+    {
+        String type = descriptor.getContentType();
+        if( m_descriptors.containsKey( type ) )
+        {
+            final String error = 
+              "Duplicate content handler descriptor type."
+              + "\nContentHandlerDescriptor: " + descriptor 
+              + "\nContent Type: " + type;
+            throw new IllegalStateException( error );
+        }
+        else
+        {
+            m_logger.fine( "registering '" + type + "' content handler" );
+            m_descriptors.put( type, descriptor );
+        }
+    }
+
+   /**
+    * Add a description of a content handler based on a supplied 
+    * prefernces object. The name of the preferences object 
+    * corresponds to an artifact type.  Request for the resolution 
+    * of URL content may be resolved by locating a content handler 
+    * plugin for the type exposed by the URL.
+    */
+    protected void addContentHandlerDescriptor( Preferences prefs )
+    {
+        ContentHandlerDescriptor descriptor = new 
DefaultContentHandlerDescriptor( m_logger, prefs );
+        addContentHandlerDescriptor( descriptor );
+    }
+
+   /**
+    * Remove a content handler descriptor.
+    * @param prefs the preferences node
+    * @return the content handler descriptor that was removed (possibly null)
+    */
+    protected ContentHandlerDescriptor removeContentHandlerDescriptor( 
Preferences prefs )
+    {
+        synchronized( m_descriptors )
+        {
+            String type = prefs.name();
+            ContentHandlerDescriptor descriptor = 
getContentHandlerDescriptor( type );
+            if( descriptor != null )
+            {
+                m_descriptors.remove( type );
+                if( descriptor instanceof DefaultContentHandlerDescriptor )
+                {
+                    DefaultContentHandlerDescriptor d = 
(DefaultContentHandlerDescriptor) descriptor;
+                    d.dispose();
+                }
+            }
+            return descriptor;
+        }
+    }
+}

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/images/misc.png
==============================================================================
Binary file. No diff available.

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/images/server.png
==============================================================================
Binary file. No diff available.

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/images/source.png
==============================================================================
Binary file. No diff available.

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/logging/StandardFormatter.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/logging/StandardFormatter.java
      (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/logging/StandardFormatter.java
      Tue May 10 14:47:13 2005
@@ -56,8 +56,9 @@
         buffer.append( lineSeparator );
         if( record.getThrown() != null ) 
         {
+            boolean trace = record.getLevel().intValue() > 900;
             Throwable cause = record.getThrown();
-            String error = ExceptionHelper.packException( cause, true );
+            String error = ExceptionHelper.packException( cause, trace );
             buffer.append( error );
         }
         return buffer.toString();

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerControllerPanel.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerControllerPanel.java
    Tue May 10 14:47:13 2005
@@ -0,0 +1,425 @@
+/*
+ * Copyright 2005 Stephen J. McConnell.
+ *
+ * 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 net.dpml.transit.prefs;
+
+import java.io.IOException;
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.event.ActionListener;
+import java.awt.event.ActionEvent;
+import java.awt.FlowLayout;
+import java.awt.BorderLayout;
+import java.awt.Component;
+import java.awt.Insets;
+import java.net.URI;
+import java.net.URL;
+import java.net.URISyntaxException;
+import java.beans.PropertyChangeEvent;
+import java.beans.PropertyChangeListener;
+import java.beans.PropertyChangeSupport;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Map;
+import java.util.Hashtable;
+import java.util.Properties;
+import java.util.prefs.Preferences;
+import java.util.prefs.PreferenceChangeListener;
+import java.util.prefs.PreferenceChangeEvent;
+
+import javax.swing.Action;
+import javax.swing.AbstractAction;
+import javax.swing.BoxLayout;
+import javax.swing.JDialog;
+import javax.swing.JTable;
+import javax.swing.JScrollPane;
+import javax.swing.JButton;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.JTextField;
+import javax.swing.JOptionPane;
+import javax.swing.border.EmptyBorder;
+import javax.swing.border.CompoundBorder;
+import javax.swing.border.TitledBorder;
+import javax.swing.event.DocumentEvent;
+import javax.swing.event.DocumentListener;
+import javax.swing.table.TableColumnModel;
+import javax.swing.table.TableColumn;
+import javax.swing.table.DefaultTableColumnModel;
+import javax.swing.JFileChooser;
+
+import net.dpml.transit.Transit;
+import net.dpml.transit.util.ExceptionHelper;
+import net.dpml.transit.content.ContentHandlerRegistry;
+import net.dpml.transit.repository.Plugin;
+
+
+/**
+ * Control panel for editing the cache preferences.
+ *
+ * @author <a href="mailto:mcconnell AT osm.net";>OSM</a>
+ */
+public class ContentHandlerControllerPanel extends JPanel implements 
PreferenceChangeListener, PropertyChangeListener, DocumentListener
+{
+    //--------------------------------------------------------------
+    // static
+    //--------------------------------------------------------------
+
+    static EmptyBorder border5 = new EmptyBorder( 5, 5, 5, 5);
+
+    //--------------------------------------------------------------
+    // state
+    //--------------------------------------------------------------
+
+    private final JDialog m_parent;
+    private JTextField m_base;
+    private JButton m_ok;
+    private JButton m_revert;
+    private JButton m_settings;
+
+    private Preferences m_preferences;
+
+    private PropertyChangeSupport m_propertyChangeSupport;
+
+    //--------------------------------------------------------------
+    // constructor
+    //--------------------------------------------------------------
+
+    public ContentHandlerControllerPanel( JDialog parent ) throws Exception 
+    {
+        m_parent = parent;
+        m_propertyChangeSupport = new PropertyChangeSupport( this );
+
+        m_preferences = Preferences.userNodeForPackage( 
ContentHandlerRegistry.class );
+
+        setLayout( new BorderLayout() );
+        setBackground( Color.white );
+
+        m_ok = new JButton( new OKAction( "OK" ) );
+        m_revert = new JButton( new RevertAction( "Undo" ) );
+        m_preferences.addPreferenceChangeListener( this );
+
+        // create a label containing an icon and label
+
+        {
+            JLabel label = 
+              IconHelper.createImageIconJLabel( 
+                Transit.class.getClassLoader(), 
"net/dpml/transit/images/source.png", "URI", "Controller URI" ); 
+            label.setBorder( new EmptyBorder( 0, 5, 0, 0 ) );
+            JPanel panel = new JPanel();
+            panel.setLayout( new BorderLayout() );
+            panel.setBackground( Color.white );
+            panel.add( label, BorderLayout.WEST );
+            add( panel, BorderLayout.NORTH );
+        }
+
+        // add a test field containing the content handler artifact uri
+
+        {
+            JPanel holder = new JPanel();
+            holder.setBackground( Color.white );
+            holder.setLayout( new BorderLayout() );
+
+            JPanel panel = new JPanel();
+            panel.setLayout( new BoxLayout( panel, BoxLayout.Y_AXIS ) );
+            panel.setBackground( Color.white );
+            panel.setBorder( new EmptyBorder( 10, 10, 10, 10 ) );
+            {
+                JPanel padding = new JPanel();
+                padding.setBackground( Color.white );
+                padding.setLayout( new BorderLayout() );
+                padding.setBorder( new EmptyBorder( 10, 2, 5, 2) );
+                String artifact = getControllerFieldTextFromPreferences();
+                m_base = new JTextField( artifact );
+                m_base.getDocument().addDocumentListener( this ); // listen 
for changes
+                m_base.setBackground( Color.white );
+                padding.add( m_base );
+                panel.add( padding );
+            }
+            {
+                JPanel settingsPanel = new JPanel();
+                settingsPanel.setBorder( 
+                  new CompoundBorder(
+                    new TitledBorder( 
+                      null, "Controller Settings", TitledBorder.LEFT, 
TitledBorder.TOP), 
+                    new EmptyBorder( 5, 5, 5, 10) 
+                  ) 
+                );
+                settingsPanel.setBackground( Color.white );
+                settingsPanel.setLayout( new BorderLayout() );
+                m_settings = new JButton( new SettingsAction( "Controller 
Settings" ) );
+                settingsPanel.add( m_settings, BorderLayout.EAST );
+                panel.add( settingsPanel );
+            }
+            holder.add( panel, BorderLayout.NORTH );
+            add( holder, BorderLayout.CENTER );
+        }
+
+        // add controls for modification of the registry controller
+
+        {
+            JPanel panel = new JPanel();
+            panel.setLayout( new FlowLayout( FlowLayout.RIGHT ) );
+            panel.add( m_revert );
+            panel.add( m_ok );
+            panel.add( new JButton( new CloseAction( "Cancel" ) ) );
+            panel.setBorder( new EmptyBorder( 10, 10, 5, 0 ) );
+            panel.setBackground( Color.white );
+            add( panel, BorderLayout.SOUTH );
+        }
+
+        m_propertyChangeSupport.addPropertyChangeListener( this );
+    }
+
+    //--------------------------------------------------------------
+    // DocumentListener
+    //--------------------------------------------------------------
+
+    public void insertUpdate( DocumentEvent event )
+    {
+        fireBaseChangedEvent();
+    }
+
+    public void removeUpdate( DocumentEvent event )
+    {
+        fireBaseChangedEvent();
+    }
+
+    public void changedUpdate( DocumentEvent event )
+    {
+        fireBaseChangedEvent();
+    }
+
+    private void fireBaseChangedEvent()
+    {
+        String artifact = getControllerFieldTextFromPreferences();
+        PropertyChangeEvent e = 
+          new PropertyChangeEvent( 
+            m_base, "base", artifact, m_base.getText() );
+        m_propertyChangeSupport.firePropertyChange( e );
+    }
+
+    //--------------------------------------------------------------
+    // PropertyChangeListener
+    //--------------------------------------------------------------
+
+   /**
+    * The actions dealing with changes to the dialog raise change events 
that 
+    * are captured here.  This listener checks changes and enables or 
disabled 
+    * the ok and undo buttons based on the state of controls relative to the 
+    * underlying preferences for the cache.
+    */
+    public void propertyChange( PropertyChangeEvent event )
+    {
+        String artifact = getControllerFieldTextFromPreferences();
+        boolean flag = ( false == artifact.equals( m_base.getText() ) );
+        m_ok.setEnabled( flag );
+        m_revert.setEnabled( flag );
+    }
+
+    private String getControllerFieldTextFromPreferences()
+    {
+        return m_preferences.get( "uri", "artifact:plugin:" );
+    }
+
+    private String getControllerPathFromPreferences()
+    {
+        return m_preferences.get( "uri", null );
+    }
+
+    public void preferenceChange( PreferenceChangeEvent event )
+    {
+        String artifact = getControllerFieldTextFromPreferences();
+        m_base.setText( artifact );
+    }
+
+    private class CloseAction extends AbstractAction
+    {
+         CloseAction( String name )
+         {
+             super( name );
+         }
+
+         public void actionPerformed( ActionEvent event )
+         {
+             m_parent.hide();
+         }
+     }
+
+    private class SettingsAction extends AbstractAction 
+    {
+        SettingsAction( String name )
+        {
+            super( name );
+            setEnabled( false );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            
+        }
+    }
+
+    private class RevertAction extends AbstractAction 
+    {
+        RevertAction( String name )
+        {
+            super( name );
+            setEnabled( false );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            String artifact = getControllerFieldTextFromPreferences();
+            String old = m_base.getText();
+            m_base.setText( artifact );
+            PropertyChangeEvent e = 
+              new PropertyChangeEvent( this, "uri", old, artifact );
+            m_propertyChangeSupport.firePropertyChange( e );
+        }
+    }
+
+    private class OKAction extends AbstractAction
+    {
+        OKAction( String name )
+        {
+            super( name );
+            setEnabled( false );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            String text = m_base.getText();
+            String artifact = getControllerFieldTextFromPreferences();
+            if( false == text.equals( artifact ) )
+            {
+                if( "".equals( text ) )
+                {
+                    m_preferences.remove( "uri" );
+                    m_parent.hide();
+                }
+                else
+                {
+                    boolean validated = validateControllerSpec( m_parent, 
text );
+                    if( validated )
+                    {
+                        m_parent.hide();
+                        m_preferences.put( "uri", text );
+                    }
+                }
+            }
+        }
+    }
+
+    private boolean validateControllerSpec( Component component, String spec 
)
+    {
+        URI uri = createControllerURI( component, spec );
+        if( null == uri )
+        {
+            return false;
+        }
+        URL url = getURLFromURI( component, uri );
+        if( null == url )
+        {
+            return false;
+        }
+        Plugin plugin = getPluginFromURL( component, url );
+        if( null == plugin )
+        {
+            return false;
+        }
+        String classname = plugin.getClassname();
+        return checkPluginClass( component, url );
+    }
+
+    private URI createControllerURI( Component component, String spec )
+    {
+        try
+        {
+            return new URI( spec );
+        }
+        catch( URISyntaxException e )
+        {
+            final String title = "Controller URI Error";
+            final String message = "Invalid uri.";
+            JOptionPane.showMessageDialog( component, message, title, 
JOptionPane.ERROR_MESSAGE );
+            return null;
+        }
+    }
+
+    private URL getURLFromURI( Component component, URI uri )
+    {
+        try
+        {
+            String spec = uri.toString();
+            return new URL( spec );
+        }
+        catch( IOException e )
+        {
+            final String title = "Controller URI Error";
+            final String message = "Cannot convert the uri to a url.";
+            JOptionPane.showMessageDialog( component, message, title, 
JOptionPane.ERROR_MESSAGE );
+            return null;
+        }
+    }
+
+    private Plugin getPluginFromURL( Component component, URL url )
+    {
+        try
+        {
+            return (Plugin) url.getContent( new Class[]{ Plugin.class } );
+        }
+        catch( Throwable e )
+        {
+            final String title = "Controller URI Error";
+            final String message = e.getMessage();
+            JOptionPane.showMessageDialog( component, message, title, 
JOptionPane.ERROR_MESSAGE );
+            return null;
+        }
+    }
+
+    private boolean checkPluginClass( Component component, URL url )
+    {
+        Class c = null;
+        try
+        {
+            c = (Class) url.getContent( new Class[]{ Class.class } );
+        }
+        catch( Throwable e )
+        {
+            final String title = "Controller URI Error";
+            final String message = e.getMessage();
+            e.printStackTrace();
+            JOptionPane.showMessageDialog( component, message, title, 
JOptionPane.ERROR_MESSAGE );
+            return false;
+        }
+        if( ContentHandlerRegistry.class.isAssignableFrom( c ) )
+        {
+            return true;
+        }
+        else
+        {
+            final String title = "Controller URI Error";
+            final String message = "Plugin class does not implement " + 
ContentHandlerRegistry.class.getName() + ".";
+            JOptionPane.showMessageDialog( component, message, title, 
JOptionPane.ERROR_MESSAGE );
+            return false;
+        }
+    }
+}

Added: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerPanel.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ContentHandlerPanel.java
      Tue May 10 14:47:13 2005
@@ -0,0 +1,404 @@
+/*
+ * Copyright 2004 Stephen J. McConnell.
+ *
+ * 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 net.dpml.transit.prefs;
+
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.event.ActionListener;
+import java.awt.event.ActionEvent;
+import java.awt.FlowLayout;
+import java.awt.BorderLayout;
+import java.awt.Component;
+import java.awt.Insets;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Map;
+import java.util.Hashtable;
+import java.util.Properties;
+import java.util.prefs.Preferences;
+
+import javax.swing.Action;
+import javax.swing.AbstractAction;
+import javax.swing.BoxLayout;
+import javax.swing.JDialog;
+import javax.swing.JTable;
+import javax.swing.JScrollPane;
+import javax.swing.JButton;
+import javax.swing.JPanel;
+import javax.swing.JLabel;
+import javax.swing.ListSelectionModel;
+import javax.swing.JOptionPane;
+import javax.swing.border.EmptyBorder;
+import javax.swing.border.CompoundBorder;
+import javax.swing.border.TitledBorder;
+import javax.swing.table.TableColumnModel;
+import javax.swing.table.TableColumn;
+import javax.swing.table.DefaultTableColumnModel;
+import javax.swing.event.ListSelectionListener;
+import javax.swing.event.ListSelectionEvent;
+
+import net.dpml.transit.Transit;
+import net.dpml.transit.util.ExceptionHelper;
+import net.dpml.transit.cache.CacheHandler;
+import net.dpml.transit.host.ResourceHost;
+import net.dpml.transit.util.Util;
+import net.dpml.transit.content.ContentHandlerRegistry;
+
+/**
+ * Runnable plugin that handles DPML environment setup.
+ *
+ * @author <a href="mailto:mcconnell AT osm.net";>OSM</a>
+ */
+public class ContentHandlerPanel extends JPanel implements 
ListSelectionListener
+{
+    //--------------------------------------------------------------
+    // static
+    //--------------------------------------------------------------
+
+    static EmptyBorder border5 = new EmptyBorder( 5, 5, 5, 5);
+
+    //--------------------------------------------------------------
+    // state
+    //--------------------------------------------------------------
+
+    private final JDialog m_parent;
+
+    private GenericTable m_table;
+
+    private JButton m_edit;
+    private JButton m_delete;
+
+    private String m_selection; // selected hostname
+
+    //--------------------------------------------------------------
+    // constructor
+    //--------------------------------------------------------------
+
+    public ContentHandlerPanel( JDialog parent ) throws Exception
+    {
+        m_parent = parent;
+
+        m_edit = new JButton( new EditAction( "Edit" ) );
+        m_delete = new JButton( new DeleteAction( "Delete" ) );
+
+        setLayout( new BorderLayout() );
+        setBorder( new EmptyBorder( 10, 6, 10, 6 ) );
+        setBackground( Color.white );
+
+        JPanel contentHandlerPanel = new JPanel();
+        contentHandlerPanel.setBackground( Color.white );
+
+         contentHandlerPanel.setLayout( new BorderLayout() );
+        TitledBorder tb = 
+          new TitledBorder( 
+            new EmptyBorder( 0,0,0,0 ), "Content Handlers", 
TitledBorder.LEFT, TitledBorder.TOP );
+        contentHandlerPanel.setBorder( new CompoundBorder( tb, border5 ) );
+
+        Preferences prefs = Preferences.userNodeForPackage( 
ContentHandlerRegistry.class );
+        TableColumnModel columns = createContentHandlerColumnModel();
+        NodeTableModel model = new NodeTableModel( prefs );
+        m_table = new GenericTable( model, columns );
+        m_table.setShowVerticalLines( false );
+        m_table.setShowHorizontalLines( false );
+        m_table.getSelectionModel().addListSelectionListener( this );
+
+        JScrollPane scroller = createScrollPanel( m_table );
+        contentHandlerPanel.add( scroller, BorderLayout.CENTER );
+        JPanel buttonHolder = new JPanel();
+        buttonHolder.setLayout( new FlowLayout( FlowLayout.RIGHT ) );
+        buttonHolder.add( new JButton( new AddAction( "Add" ) ) );
+        buttonHolder.add( m_edit );
+        buttonHolder.add( m_delete );
+        buttonHolder.setBorder( new EmptyBorder( 10, 10, 5, 0 ) );
+        buttonHolder.setBackground( Color.white );
+        contentHandlerPanel.add( buttonHolder, BorderLayout.SOUTH );
+
+        JPanel controllerPanel = createContentHandlerControllerPanel( parent 
);
+
+        add( controllerPanel, BorderLayout.NORTH );
+        add( contentHandlerPanel, BorderLayout.CENTER );
+    }
+
+    //--------------------------------------------------------------
+    // utilities
+    //--------------------------------------------------------------
+
+    private JPanel createContentHandlerControllerPanel( JDialog parent )
+    {
+        JLabel label = 
+          IconHelper.createImageIconJLabel( 
+            ResourcePanel.class.getClassLoader(),
+            "net/dpml/transit/images/misc.png", 
+            "Artifact", 
+            "Content Handler Controller settings." ); 
+        label.setBorder( new EmptyBorder( 0, 5, 0, 0 ) );
+
+        JPanel holder = new JPanel();
+         holder.setLayout( new BoxLayout( holder, BoxLayout.Y_AXIS ) );
+        holder.setBorder( new EmptyBorder( 0, 6, 0, 6 ) );
+        holder.setBackground( Color.white );
+        JPanel cache = new JPanel();
+        cache.setBackground( Color.white );
+         cache.setLayout( new BorderLayout() );
+        cache.add( label, BorderLayout.WEST );
+        cache.setBorder( 
+          new CompoundBorder(
+            new TitledBorder( null, "Cache", TitledBorder.LEFT, 
TitledBorder.TOP), border5 ) );
+        JButton button = new JButton( new ControllerAction( parent, 
"Controller" ) );
+        JPanel cacheButtonHolder = new JPanel();
+        cacheButtonHolder.setBackground( Color.white );
+         cacheButtonHolder.setLayout( new BorderLayout() );
+        cacheButtonHolder.add( button, BorderLayout.SOUTH );
+        cache.add( cacheButtonHolder, BorderLayout.EAST );
+        holder.add( cache );
+        return holder;
+    }
+
+    private static class ControllerAction extends AbstractAction
+    {
+        JDialog m_parent;
+
+        ControllerAction( JDialog parent, String name )
+        {
+            super( name );
+            m_parent = parent;
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            try
+            {
+                JDialog dialog = new JDialog( m_parent, true );
+                dialog.setTitle( "Content Handler Controller" );
+                Dimension size = new Dimension( 400, 240 );
+
+                JPanel frame = new JPanel();
+                frame.setLayout( new BorderLayout() );
+                frame.setBackground( Color.white );
+                frame.setBorder( new EmptyBorder( 10, 6, 0, 6 ) );
+    
+                JPanel panel = new ContentHandlerControllerPanel( dialog );
+                frame.add( panel, BorderLayout.CENTER );
+                dialog.setContentPane( frame );
+                dialog.setSize( size );
+                dialog.setLocationRelativeTo( (Component) event.getSource() 
);
+                dialog.setResizable( true );
+                dialog.setVisible(true);
+            }
+            catch( Throwable e )
+            {
+                final String error = 
+                  "Unexpected error while attempting to handle the 
'Controller' action. "
+                  + "\nCODEBASE: "
+                  + 
ResourcePanel.class.getProtectionDomain().getCodeSource().getLocation().toString();
+                String message = ExceptionHelper.packException( error, e, 
true );
+                System.err.println( message );
+            }
+        }
+
+        private static class CloseAction extends AbstractAction
+        {
+             private JDialog m_dialog;
+
+             CloseAction( String name, JDialog dialog )
+             {
+                 super( name );
+                 m_dialog = dialog;
+             }
+
+             public void actionPerformed( ActionEvent event )
+             {
+                 m_dialog.hide();
+             }
+        }
+    }
+
+   /**
+    * Creation of a parameterized scroll pane.
+    * @param view the viewport view
+    * @return the scroll pane wrapping the supplied view
+    */
+    private static JScrollPane createScrollPanel( Component view )
+    {
+        JScrollPane scroller = new JScrollPane();
+        scroller.setVerticalScrollBarPolicy( 
+          JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED );
+        scroller.setHorizontalScrollBarPolicy( 
+          JScrollPane.HORIZONTAL_SCROLLBAR_NEVER );
+        scroller.getViewport().setBackground( Color.white );
+        scroller.setViewportView( view );
+        return scroller;
+    }
+
+   /**
+    * Utility method to construct the hosts table column model.
+    * @return the table
+    */
+    private static TableColumnModel createContentHandlerColumnModel()
+    {
+         TableColumn iconColumn = new TableColumn( 0, 30, new 
DefaultCellRenderer(), null );
+        iconColumn.setHeaderValue( "" );
+         iconColumn.setMaxWidth( 30 );
+         iconColumn.setMinWidth( 30 );
+         TableColumn typeColumn = new TableColumn( 1, 100, new 
DefaultCellRenderer(), null );
+        typeColumn.setHeaderValue( "Type" );
+        TableColumnModel model = new DefaultTableColumnModel();
+         model.addColumn( iconColumn  );
+         model.addColumn( typeColumn );
+         return model;
+    }
+
+    private class AddAction extends AbstractAction
+    {
+        public AddAction( String name )
+        {
+             super( name );
+             setEnabled( true );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            String name = JOptionPane.showInputDialog( m_parent, "Content 
Handler Name:" );
+            if( null == name )
+            {
+                return;
+            }
+
+            /*
+            try
+            {
+                JDialog dialog = new JDialog( m_parent, true );
+                dialog.setTitle( "Resource Host: " + name );
+                JPanel panel = new HostPanel( dialog, name );
+                dialog.setContentPane( panel );
+                Dimension size = new Dimension( 400, 360 );
+                dialog.setSize( size );
+                dialog.setLocationRelativeTo( (Component) event.getSource() 
);
+                dialog.setResizable( true );
+                dialog.setVisible( true );
+            }
+            catch( Throwable e )
+            {
+                final String error = 
+                  "Unexpected error while attempting to construct host 
dialog."
+                  + "\nCODEBASE: "
+                  + 
ResourcePanel.class.getProtectionDomain().getCodeSource().getLocation().toString();
+                String message = ExceptionHelper.packException( error, e, 
true );
+                System.out.println( message );
+            }
+            */
+        }
+    }
+
+    private class EditAction extends AbstractAction
+    {
+        public EditAction( String name )
+        {
+             super( name );
+             setEnabled( false );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            /*
+            try
+            {
+                JDialog dialog = new JDialog( m_parent, true );
+                dialog.setTitle( "Resource Host: " + m_selection );
+                JPanel panel = new HostPanel( dialog, m_selection );
+                dialog.setContentPane( panel );
+                Dimension size = new Dimension( 400, 360 );
+                dialog.setSize( size );
+                dialog.setLocationRelativeTo( (Component) event.getSource() 
);
+                dialog.setResizable( true );
+                dialog.setVisible( true );
+            }
+            catch( Throwable e )
+            {
+                final String error = 
+                  "Unexpected error while attempting to construct host 
dialog."
+                  + "\nCODEBASE: "
+                  + 
ResourcePanel.class.getProtectionDomain().getCodeSource().getLocation().toString();
+                String message = ExceptionHelper.packException( error, e, 
true );
+                System.out.println( message );
+            }
+            */
+        }
+    }
+
+    private class DeleteAction extends AbstractAction
+    {
+        public DeleteAction( String name )
+        {
+             super( name );
+             setEnabled( false );
+        }
+
+        public void actionPerformed( ActionEvent event )
+        {
+            if( null == m_selection )
+            {
+                return;
+            }
+            /*
+            Preferences hosts = Preferences.userNodeForPackage( 
ResourceHost.class );
+            Preferences target = hosts.node( m_selection );
+            try
+            {
+                target.removeNode();
+            }
+            catch( Throwable e )
+            {
+                final String error = 
+                  "Unexpected error while attempting to delete a host 
preferences node."
+                  + "\nCODEBASE: "
+                  + 
ResourcePanel.class.getProtectionDomain().getCodeSource().getLocation().toString();
+                String message = ExceptionHelper.packException( error, e, 
true );
+                System.out.println( message );
+            }
+            */
+        }
+    }
+
+    public void valueChanged( ListSelectionEvent event )
+    {
+        if( !event.getValueIsAdjusting() )
+        {
+            ListSelectionModel model = m_table.getSelectionModel();
+            synchronized( model )
+            {
+                int n = model.getMinSelectionIndex();
+                if( ( n == model.getMaxSelectionIndex() ) && ( n > -1 ) ) 
+                {
+                    m_selection = (String) m_table.getValueAt( n, 1 );
+                    m_edit.setEnabled( true );
+                    m_delete.setEnabled( true );
+                }
+                else
+                {
+                    m_selection = null;
+                    m_edit.setEnabled( false );
+                    m_delete.setEnabled( false );
+                }
+            }
+        }
+    }
+}

Copied: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/GenericTable.java
 (from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTable.java)
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTable.java
       (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/GenericTable.java
     Tue May 10 14:47:13 2005
@@ -34,7 +34,7 @@
 /**
  * A table mapping the collection of preference nodes to hosts.
  */
-public class HostsTable extends JTable implements ListSelectionListener, 
FocusListener
+public class GenericTable extends JTable implements ListSelectionListener, 
FocusListener
 {
     
//--------------------------------------------------------------------------
     // static
@@ -84,7 +84,7 @@
     * @param data a table model containing the data to layout in view
     * @param columns the table column model to apply
     */
-    public HostsTable( TableModel data, TableColumnModel columns )
+    public GenericTable( TableModel data, TableColumnModel columns )
     {
         super( data, columns );
 

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostPanel.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostPanel.java
        (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostPanel.java
        Tue May 10 14:47:13 2005
@@ -130,7 +130,7 @@
 
         m_label = 
           IconHelper.createImageIconJLabel( 
-            Transit.class.getClassLoader(), 
"net/dpml/transit/images/network.png", "Host", "Host: " + name );
+            Transit.class.getClassLoader(), 
"net/dpml/transit/images/server.png", "Host", "Host: " + name );
 
         m_label.setBorder( new EmptyBorder( 0, 5, 0, 10 ) );
         JPanel labelPanel = new JPanel();

Copied: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/NodeTableModel.java
 (from r2485, 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTableModel.java)
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/HostsTableModel.java
  (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/NodeTableModel.java
   Tue May 10 14:47:13 2005
@@ -38,7 +38,7 @@
 /**
  * Table model used to manage features of an adapter.
  */
-class HostsTableModel extends AbstractTableModel implements 
NodeChangeListener
+class NodeTableModel extends AbstractTableModel implements NodeChangeListener
 {
     
//--------------------------------------------------------------------------
     // static
@@ -70,6 +70,8 @@
     private static final Icon FEATURE_ICON = 
       IconHelper.createImageIcon( Transit.class.getClassLoader(), ICON_PATH, 
"Features" );
 
+    private final Preferences m_preferences;
+
     
//--------------------------------------------------------------------------
     // constructor
     
//--------------------------------------------------------------------------
@@ -78,9 +80,10 @@
     * Creation of a new feature table model.
     * @param entity the reference entity
     */
-    public HostsTableModel( Preferences prefs ) 
+    public NodeTableModel( Preferences prefs ) 
     {
         super();
+        m_preferences = prefs;
         prefs.addNodeChangeListener( this );
     }
 
@@ -104,7 +107,7 @@
     }
 
     
//--------------------------------------------------------------------------
-    // HostsTableModel
+    // NodeTableModel
     
//--------------------------------------------------------------------------
 
    /**
@@ -125,7 +128,7 @@
     { 
         try
         {
-            return getHostPreferences().childrenNames().length;
+            return getPreferences().childrenNames().length;
         }
         catch( Throwable e )
         {
@@ -162,7 +165,7 @@
     {
         try
         {
-            String[] names = getHostPreferences().childrenNames();
+            String[] names = getPreferences().childrenNames();
             return names[ row ];
         }
         catch( Throwable e )
@@ -171,8 +174,8 @@
         }
     }
 
-    Preferences getHostPreferences()
+    Preferences getPreferences()
     {
-        return Preferences.userNodeForPackage( ResourceHost.class );
+        return m_preferences;
     }
 }

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ResourcePanel.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ResourcePanel.java
    (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/ResourcePanel.java
    Tue May 10 14:47:13 2005
@@ -82,7 +82,7 @@
 
     private final JDialog m_parent;
 
-    private HostsTable m_table;
+    private GenericTable m_table;
 
     private JButton m_edit;
     private JButton m_delete;
@@ -115,8 +115,8 @@
 
         Preferences hosts = Preferences.userNodeForPackage( 
ResourceHost.class );
         TableColumnModel columns = createHostsColumnModel();
-        HostsTableModel model = new HostsTableModel( hosts );
-        m_table = new HostsTable( model, columns );
+        NodeTableModel model = new NodeTableModel( hosts );
+        m_table = new GenericTable( model, columns );
         m_table.setShowVerticalLines( false );
         m_table.setShowHorizontalLines( false );
         m_table.getSelectionModel().addListSelectionListener( this );

Modified: 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/TransitDialog.java
==============================================================================
--- 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/TransitDialog.java
    (original)
+++ 
development/main/transit/core/handler/src/main/net/dpml/transit/prefs/TransitDialog.java
    Tue May 10 14:47:13 2005
@@ -123,8 +123,9 @@
         JPanel panel = new JPanel();
 
         ResourcePanel transitPanel = new ResourcePanel( this );
-        JPanel transitTab = createNamedPanel( "Transit Preferences" , 
transitPanel );
+        ContentHandlerPanel contentPanel = new ContentHandlerPanel( this );
         tabbedPane.addTab( "Resources", transitPanel );
+        tabbedPane.addTab( "Content", contentPanel );
         tabbedPane.addTab( "Logging", new JPanel() );
         tabbedPane.addTab( "Properties", new JPanel() );
 

Modified: 
development/main/transit/core/handler/src/test/net/dpml/transit/test/LinkTestCase.java
==============================================================================
--- 
development/main/transit/core/handler/src/test/net/dpml/transit/test/LinkTestCase.java
      (original)
+++ 
development/main/transit/core/handler/src/test/net/dpml/transit/test/LinkTestCase.java
      Tue May 10 14:47:13 2005
@@ -38,6 +38,7 @@
     protected void setUp() throws Exception
     {
         System.setProperty( "java.protocol.handler.pkgs", "net.dpml.transit" 
);
+        System.setProperty( "java.util.logging.config.class", 
"net.dpml.transit.logging.ConfigurationHandler" );
         System.setProperty( "dpml.transit.secured.disable", "true" );
         System.setProperty( "dpml.transit.authority.file", 
"target/test/test.authority" );
         String test = System.getProperty( "project.dir" );

Modified: 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OfflineTestCase.java
==============================================================================
--- 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OfflineTestCase.java
   (original)
+++ 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OfflineTestCase.java
   Tue May 10 14:47:13 2005
@@ -42,6 +42,7 @@
         throws Exception
     {
         System.setProperty( "java.protocol.handler.pkgs", "net.dpml.transit" 
);
+        System.setProperty( "java.util.logging.config.class", 
"net.dpml.transit.logging.ConfigurationHandler" );
         System.setProperty( "dpml.transit.secured.disable", "true" );
         System.setProperty( "dpml.transit.authority.file", 
"target/test/test.authority" );
         String test = System.getProperty( "project.dir" );

Modified: 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OnlineTestCase.java
==============================================================================
--- 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OnlineTestCase.java
    (original)
+++ 
development/main/transit/core/handler/src/test/net/dpml/transit/test/OnlineTestCase.java
    Tue May 10 14:47:13 2005
@@ -39,6 +39,7 @@
     protected void setUp() throws Exception
     {
         System.setProperty( "java.protocol.handler.pkgs", "net.dpml.transit" 
);
+        System.setProperty( "java.util.logging.config.class", 
"net.dpml.transit.logging.ConfigurationHandler" );
     }
 
     public void testStackedJarUrl() throws Exception