DPML Notify

[mcconnell AT netcompartner.com]

Author: mcconnell
Date: Tue Dec 14 17:53:53 2004
New Revision: 1179

Added:
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/AbstractMonitorRouter.java
   (contents, props changed)
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/NullMonitor.java
   (contents, props changed)
Modified:
   development/main/transit/handler/src/main/net/dpml/transit/Main.java
   development/main/transit/handler/src/main/net/dpml/transit/Transit.java
   
development/main/transit/handler/src/main/net/dpml/transit/adapter/AbstractAdapter.java
   
development/main/transit/handler/src/main/net/dpml/transit/adapter/CacheMonitorAdapter.java
   
development/main/transit/handler/src/main/net/dpml/transit/adapter/ConsoleAdapter.java
   
development/main/transit/handler/src/main/net/dpml/transit/artifact/SecuredTransitContext.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/CacheMonitorRouter.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/ConnectionMonitorRouter.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/Monitor.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/NetworkMonitorRouter.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/RepositoryMonitorRouter.java
   
development/main/transit/handler/src/main/net/dpml/transit/monitors/Router.java
Log:
Updates to the transit system to enable the association of a boostrap monitor 
so we can look inside to see what is happening from the very beginning.

Modified: development/main/transit/handler/src/main/net/dpml/transit/Main.java
==============================================================================
--- development/main/transit/handler/src/main/net/dpml/transit/Main.java      
  (original)
+++ development/main/transit/handler/src/main/net/dpml/transit/Main.java      
  Tue Dec 14 17:53:53 2004
@@ -61,22 +61,16 @@
     public static void main( final String[] args )
         throws Exception
     {
-        String path = System.getProperty( BOOTSTRAP_URI_KEY );
-        if( null == path )
-        {
-            final String error = 
-              "The system property '"
-              + BOOTSTRAP_URI_KEY
-              + "' is undefined.";
-            throw new IllegalStateException( error );
-        }
-
         //
         // Setup transit protocol handler
         //
 
         System.setProperty( "java.protocol.handler.pkgs", "net.dpml.transit" 
);
 
+        //
+        // Setup debug policy
+        //
+
         boolean debug = false;
         for( int i=0; i < args.length; i++ )
         {
@@ -86,9 +80,11 @@
                  break;
             }
         }
+
         String[] arguments = collapseArgs( args );
 
-        Transit transit = Transit.getInstance();
+        Monitor monitor = new BootstrapMonitor( debug );
+        Transit transit = Transit.getInstance( monitor );
 
         Adapter adapter = new ConsoleAdapter( debug );
         RepositoryMonitor repoMonitor = new RepositoryMonitorAdapter( 
adapter );
@@ -99,6 +95,22 @@
         transit.getCacheMonitorRouter().addMonitor( cacheMonitor );
         transit.getNetworkMonitorRouter().addMonitor( netMonitor );
 
+        //
+        // get the bootstrap plugin
+        //
+
+        String path = System.getProperty( BOOTSTRAP_URI_KEY );
+        if( null == path )
+        {
+            final String error = 
+              "The system property '"
+              + BOOTSTRAP_URI_KEY
+              + "' is undefined.";
+            System.err.println( error );
+            System.getProperties().list( System.err );
+            throw new IllegalStateException( error );
+        }
+
         URI uri = Artifact.createArtifact( path ).toURI();
         Monitor[] monitors = new Monitor[]{repoMonitor, cacheMonitor, 
netMonitor};
         Object[] params = new Object[]{monitors, arguments};
@@ -135,5 +147,39 @@
     {
         // disabled
     }
+
+    private static class BootstrapMonitor implements Monitor
+    {
+        private static final String TAG = "[transit] ";
+        private final boolean m_trace;
+
+        BootstrapMonitor( boolean trace )
+        {
+            m_trace = trace;
+        }
+
+       /**
+        * Test is trace monitoring is enabled.
+        * @return true if debug trace messages are enabled elese false
+        */
+        public boolean isTraceEnabled()
+        {
+            return m_trace;
+        }
+
+       /**
+        * Process a trace message.
+        *
+        * @param message the trace level message
+        */
+        public void trace( String message )
+        {
+            if( isTraceEnabled() )
+            {
+                System.out.print( TAG );
+                System.out.println( message );
+            }
+        }
+    }
 }
 

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/Transit.java
==============================================================================
--- development/main/transit/handler/src/main/net/dpml/transit/Transit.java   
  (original)
+++ development/main/transit/handler/src/main/net/dpml/transit/Transit.java   
  Tue Dec 14 17:53:53 2004
@@ -26,9 +26,11 @@
 
 import net.dpml.transit.artifact.SecuredTransitContext;
 
+import net.dpml.transit.monitors.Monitor;
 import net.dpml.transit.monitors.RepositoryMonitorRouter;
 import net.dpml.transit.monitors.CacheMonitorRouter;
 import net.dpml.transit.monitors.NetworkMonitorRouter;
+import net.dpml.transit.monitors.NullMonitor;
 
 import net.dpml.transit.repository.Repository;
 import net.dpml.transit.repository.StandardLoader;
@@ -51,6 +53,11 @@
     public static final String HOME_SYMBOL =         "DPML_HOME";
 
    /**
+    * Transit trace policy system property key.
+    */
+    public static final String TRACE_KEY =         
"dpml.transit.trace.policy";
+
+   /**
     * Singleton transit instance.
     */
     private static Transit transitSingletonInstance;
@@ -90,11 +97,28 @@
     public static Transit getInstance()
         throws TransitException
     {
+        return Transit.getInstance( new NullMonitor() );
+    }
+
+   /**
+    * Returns the singleton instance of the transit system.  If this method
+    * has already been invoked the monitor argument will be ignored.
+    * @param monitor the bootstrap monitor
+    * @return the singleton transit instance
+    * @exception TransitException if an error occurs during establishment
+    */
+    public static Transit getInstance( Monitor monitor )
+        throws TransitException
+    {
+        if( null == monitor ) 
+        {
+            throw new NullPointerException( "monitor" );
+        }
         synchronized( Transit.class )
         {
             if( transitSingletonInstance == null )
             {
-                transitSingletonInstance = new Transit();
+                transitSingletonInstance = new Transit( monitor );
             }
             return transitSingletonInstance;
         }
@@ -102,17 +126,22 @@
 
    /**
     * Private constructor of a transit instance.
+    * @param monitor the bootstrap monitor
     * @exception TransitException if an establishment error occurs
     */
-    private Transit()
+    private Transit( Monitor monitor )
         throws TransitException
     {
         try
         {
-            SecuredTransitContext.create(); // Ensure secured environment.
-            m_repositoryMonitor = new RepositoryMonitorRouter();
-            m_cacheMonitor = new CacheMonitorRouter();
-            m_networkMonitor = new NetworkMonitorRouter();
+            if( monitor.isTraceEnabled() )
+            {
+                monitor.trace( "creating transit instance" );
+            }
+            SecuredTransitContext.create( monitor ); // Ensure secured 
environment.
+            m_repositoryMonitor = new RepositoryMonitorRouter( monitor);
+            m_cacheMonitor = new CacheMonitorRouter( monitor );
+            m_networkMonitor = new NetworkMonitorRouter( monitor );
         }
         catch( Throwable e )
         {

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/adapter/AbstractAdapter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/adapter/AbstractAdapter.java
     (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/adapter/AbstractAdapter.java
     Tue Dec 14 17:53:53 2004
@@ -47,4 +47,28 @@
     {
         return m_adapter;
     }
+
+   /**
+    * Test is debug trace monitoring is enabled.
+    * @return true if debug trace messages are enabled else false
+    */
+    public boolean isTraceEnabled()
+    {
+        return getAdapter().isDebugEnabled();
+    }
+
+   /**
+    * Notify the monitor of a trace level message to log.  An implement
+    * is responsible for checking if trace debug logging is enabled 
+    * before handling content.
+    *
+    * @param message the trace level message to log
+    */
+    public void trace( String message )
+    {
+        if( getAdapter().isDebugEnabled() )
+        {
+            getAdapter().debug( message );
+        }
+    }
 }

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/adapter/CacheMonitorAdapter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/adapter/CacheMonitorAdapter.java
 (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/adapter/CacheMonitorAdapter.java
 Tue Dec 14 17:53:53 2004
@@ -59,10 +59,6 @@
     */
     public void addedToLocalCache( URL resource, File localFile )
     {
-        if( getAdapter().isDebugEnabled() )
-        {
-            getAdapter().debug( "added [" + resource + "] to cache as [" + 
localFile + "]" );
-        }
     }
 
    /**

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/adapter/ConsoleAdapter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/adapter/ConsoleAdapter.java
      (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/adapter/ConsoleAdapter.java
      Tue Dec 14 17:53:53 2004
@@ -33,6 +33,8 @@
     */
     private static final int KBYTE = 1024;
 
+    private static final String TAG = "[transit] ";
+
    /**
     * The debug mode.
     */
@@ -83,7 +85,7 @@
     {
         if( m_debug ) 
         {
-            System.out.println( message );
+            log( message );
         }
     }
 
@@ -93,7 +95,7 @@
     */
     public void info( String message )
     {
-        System.out.println( message );
+        log( message );
     }
 
    /**
@@ -102,7 +104,7 @@
     */
     public void warn( String message )
     {
-        System.out.println( message );
+        log( message );
     }
 
    /**
@@ -122,7 +124,7 @@
     public void error( String message, Throwable e )
     {
         String error = ExceptionHelper.packException( message, e, m_debug );
-        System.out.println( error );
+        log( error );
     }
 
     /**
@@ -135,7 +137,7 @@
     {
         if( isAnt() && total == count )
         {
-            System.out.println( "downloaded: " + resource );
+            log( "downloaded: " + resource );
             return;
         }
 
@@ -145,7 +147,7 @@
 
             String value = getFranctionalValue( count );
             int pad = max.length() - value.length();
-            StringBuffer buffer = new StringBuffer( "Progress: " );
+            StringBuffer buffer = new StringBuffer( TAG + "Progress: " );
             for( int i=0; i < pad; i++ )
             {
                 buffer.append( " " );
@@ -219,5 +221,11 @@
              return value; 
         }
     }
+
+    private void log( String message )
+    {
+        System.out.print( TAG );
+        System.out.println( message );
+    }
 }
 

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/artifact/SecuredTransitContext.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/artifact/SecuredTransitContext.java
      (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/artifact/SecuredTransitContext.java
      Tue Dec 14 17:53:53 2004
@@ -29,6 +29,8 @@
 
 import net.dpml.transit.Transit;
 import net.dpml.transit.TransitException;
+import net.dpml.transit.monitors.Monitor;
+import net.dpml.transit.monitors.NullMonitor;
 
 /**
  * The initial context of the transit system.
@@ -85,7 +87,11 @@
    /**
     * The singleton transit context.
     */
-    private static SecuredTransitContext secuteTransitContext;
+    private static SecuredTransitContext secureTransitContext;
+
+    //------------------------------------------------------------------
+    // state
+    //------------------------------------------------------------------
 
    /**
     * The cache handler.
@@ -102,6 +108,10 @@
     */
     private ResourceHost[] m_resourceHosts;
 
+    //------------------------------------------------------------------
+    // implementation
+    //------------------------------------------------------------------
+
    /**
     * Creation of the transit context.  If the transit context has already 
     * been established the method returns the singeton context otherwise a 
new context
@@ -113,19 +123,42 @@
     public static SecuredTransitContext create()
         throws TransitException
     {
-        if( secuteTransitContext != null )
+        return SecuredTransitContext.create( new NullMonitor() );
+    }
+
+   /**
+    * Creation of the transit context.  If the transit context has already 
+    * been established the method returns the singeton context otherwise a 
new context
+    * is created relative to the authoritve url and returned.
+    *
+    * @param monitor the bootstrap monitor
+    * @return the secured transit context
+    * @exception TransitException if an error occurs during context creation
+    */
+    public static SecuredTransitContext create( final Monitor monitor )
+        throws TransitException
+    {
+        if( secureTransitContext != null )
+        {
+            return secureTransitContext;
+        }
+        if( null == monitor )
+        {
+            throw new NullPointerException( "monitor" );
+        }
+        if( monitor.isTraceEnabled() )
         {
-            return secuteTransitContext;
+            monitor.trace( "creating secure transit context" );
         }
         try
         {
-            URL authorative = establishAuthority();
+            URL authorative = establishAuthority( monitor );
             ResourceHostFactory rhFactory = new ResourceHostFactory( 
authorative );
             ResourceHost[] hosts = rhFactory.createResourceHosts();
             CacheHandlerFactory chFactory = new CacheHandlerFactory( 
authorative );
             CacheHandler ch = chFactory.createCacheHandler( hosts );
-            secuteTransitContext = new SecuredTransitContext( authorative, 
hosts, ch );
-            return secuteTransitContext;
+            secureTransitContext = new SecuredTransitContext( authorative, 
hosts, ch );
+            return secureTransitContext;
         } 
         catch( IOException e )
         {
@@ -202,7 +235,7 @@
     * @return the authorative url
     * @exception TransitException if an error occurs during authority url 
creation
     */
-    private static URL establishAuthority()
+    private static URL establishAuthority( final Monitor monitor )
         throws TransitException
     {
         try
@@ -225,6 +258,14 @@
                 } 
                 else
                 {
+                    if( monitor.isTraceEnabled() )
+                    {
+                        final String message = 
+                          "using system property 
'dpml.transit.authority.file' ["
+                          + path
+                          + "]";
+                        monitor.trace( message );
+                    }
                     return useForAuthority( authorativeFile );
                 }
             }
@@ -239,6 +280,14 @@
             artifactAuthFile = new File( transitDir, AUTHORITY_FILENAME );
             if( artifactAuthFile.exists() )
             {
+                if( monitor.isTraceEnabled() )
+                {
+                    final String message = 
+                      "using authority file ["
+                      + artifactAuthFile 
+                      + "]";
+                    monitor.trace( message );
+                }
                 return useForAuthority( artifactAuthFile );
             }
 
@@ -251,6 +300,14 @@
             artifactAuthFile = new File( extlib, AUTHORITY_FILENAME );
             if( artifactAuthFile.exists() )
             {
+                if( monitor.isTraceEnabled() )
+                {
+                    final String message = 
+                      "using extension authority file ["
+                      + artifactAuthFile 
+                      + "]";
+                    monitor.trace( message );
+                }
                 return useForAuthority( artifactAuthFile );
             }
 
@@ -260,12 +317,21 @@
             // authority directory.
             //
 
+            if( monitor.isTraceEnabled() )
+            {
+                final String message = 
+                  "using transit home as default authorative source ["
+                  + artifactAuthFile 
+                  + "]";
+                monitor.trace( message );
+            }
+
             return new File( Transit.HOME, "transit" ).toURL();
 
         } 
         catch( Exception e )
         {
-            throw new TransitException( "Artifact AUTHORITY can not be 
established.", e );
+            throw new TransitException( "Artifact AUTHORITY cannot be 
established.", e );
         }
     }
 

Added: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/AbstractMonitorRouter.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/AbstractMonitorRouter.java
      Tue Dec 14 17:53:53 2004
@@ -0,0 +1,154 @@
+/* 
+ * Copyright 2004 Niclas Hedhman.
+ *
+ * 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.monitors;
+
+import java.net.URI;
+import java.lang.reflect.Constructor;
+ 
+import java.util.ArrayList;
+import java.util.Iterator;
+
+/**
+ * A repository monitor router handles mutlicast distribution of monitor 
events to 
+ * a set of subscribed monitors.
+ */
+public class AbstractMonitorRouter implements Router, Monitor
+{
+    //--------------------------------------------------------------------
+    // static
+    //--------------------------------------------------------------------
+
+    private static final Monitor[] EMPTY_MONITORS = new Monitor[0];
+
+    //--------------------------------------------------------------------
+    // state
+    //--------------------------------------------------------------------
+
+   /**
+    * List of attached monitors.
+    */
+    private ArrayList m_monitors;
+
+   /**
+    * The trace policy.
+    */
+    private final Monitor m_trace;
+
+    //--------------------------------------------------------------------
+    // constructors
+    //--------------------------------------------------------------------
+
+    public AbstractMonitorRouter( Monitor trace )
+    {
+        m_trace = trace;
+    }
+   
+    //--------------------------------------------------------------------
+    // Router
+    //--------------------------------------------------------------------
+
+   /**
+    * Add a monitor to the set of monitors managed by this router.
+    * @param monitor the monitor to add
+    */
+    public void addMonitor( Monitor monitor )
+    {
+        synchronized( this )
+        {
+            ArrayList list;
+            if( m_monitors == null )
+            {
+                list = new ArrayList();
+            }
+            else
+            {
+                list = (ArrayList) m_monitors.clone();
+            }
+            list.add( monitor );
+            m_monitors = list;
+        }
+    }
+    
+   /**
+    * Remove a monitor from the set of monitors managed by this router.
+    * @param monitor the monitor to remove
+    */
+    public void removeMonitor( Monitor monitor )
+    {
+        synchronized( this )
+        {
+            if( m_monitors == null )
+            {
+                return;
+            }
+            ArrayList list = (ArrayList) m_monitors.clone();
+            list.remove( monitor );
+            if( list.size() == 0 )
+            {
+                m_monitors = null;
+            }
+            else
+            {
+                m_monitors = list;
+            }
+        }
+    }
+
+   /**
+    * Return the list of monitors.
+    * @return an array of connected monitors
+    */
+    Monitor[] getMonitors()
+    {
+        if( null == m_monitors ) 
+        {
+            return EMPTY_MONITORS;
+        }
+        else
+        {
+            return (Monitor[]) m_monitors.toArray( new Monitor[0] );
+        }
+    }
+
+    //--------------------------------------------------------------------
+    // Monitor
+    //--------------------------------------------------------------------
+
+   /**
+    * Test is debug trace monitoring is enabled.
+    * @return true if debug trace messages are enabled else false
+    */
+    public boolean isTraceEnabled()
+    {
+        return m_trace.isTraceEnabled();
+    }
+
+   /**
+    * Notify the monitor of a trace level message to log.  An implement
+    * is responsible for checking if trace debug logging is enabled 
+    * before handling content.
+    *
+    * @param message the trace level message to log
+    */
+    public void trace( String message )
+    {
+        m_trace.trace( message );
+    }
+}
+ 

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/CacheMonitorRouter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/CacheMonitorRouter.java
 (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/CacheMonitorRouter.java
 Tue Dec 14 17:53:53 2004
@@ -31,29 +31,33 @@
  * The cache monitor router is responsible for the dispatiching of cache 
monitor 
  * events to registered monitors.
  */
-public class CacheMonitorRouter
+public class CacheMonitorRouter extends AbstractMonitorRouter
     implements CacheMonitor, Router
 {
-   /**
-    * List of assigned monitors.
-    */
-    private ArrayList m_monitors;
-   
+    //--------------------------------------------------------------------
+    // constructors
+    //--------------------------------------------------------------------
+
+    public CacheMonitorRouter( Monitor trace )
+    {
+        super( trace );
+    }
+
+    //--------------------------------------------------------------------
+    // CacheMonitor
+    //--------------------------------------------------------------------
+
    /**
     * Notify all monitors that a request for an artifact has been received.
     * @param artifact the requested artifact
     */ 
     public void resourceRequested( Artifact artifact )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.resourceRequested( artifact );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.resourceRequested( artifact );
         }
     }
     
@@ -64,15 +68,11 @@
     */ 
     public void addedToLocalCache( URL resource, File localFile )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.addedToLocalCache( resource, localFile );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.addedToLocalCache( resource, localFile );
         }
     }
     
@@ -83,15 +83,11 @@
     */ 
     public void updatedLocalCache( URL resource, File localFile )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.updatedLocalCache( resource, localFile );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.addedToLocalCache( resource, localFile );
         }
     }
     
@@ -102,15 +98,11 @@
     */ 
     public void removedFromLocalCache( URL resource, File localFile )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.removedFromLocalCache( resource, localFile );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.removedFromLocalCache( resource, localFile );
         }
     }
     
@@ -122,15 +114,11 @@
     */ 
     public void failedDownloadFromHost( String host, Artifact artifact, 
Exception cause )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.failedDownloadFromHost( host, artifact, cause );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.failedDownloadFromHost( host, artifact, cause );
         }
     }
     
@@ -140,15 +128,11 @@
     */ 
     public void failedDownload( Artifact artifact )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            CacheMonitor mon = (CacheMonitor) list.next();
-            mon.failedDownload( artifact );
+            CacheMonitor monitor = (CacheMonitor) monitors[i];
+            monitor.failedDownload( artifact );
         }
     }
 
@@ -159,48 +143,13 @@
     */ 
     public void addMonitor( Monitor monitor ) throws IllegalArgumentException
     {
-        if( !( monitor instanceof CacheMonitor ) )
+        if( !( monitor instanceof CacheMonitor) )
         {
             throw new IllegalArgumentException( "monitor must be 
CacheMonitor type." );
         }
-        synchronized( this )
-        {
-            ArrayList list;
-            if( m_monitors == null )
-            {
-                list = new ArrayList();
-            }
-            else
-            {
-                list = (ArrayList) m_monitors.clone();
-            }
-            list.add( monitor );
-            m_monitors = list;
-        }
-    }
-    
-   /**
-    * Remove of a monitor to the list of monitors maintained by this router.
-    * @param monitor the monitor to remove
-    */ 
-    public void removeMonitor( Monitor monitor )
-    {
-        synchronized( this )
+        else
         {
-            if( m_monitors == null )
-            {
-                return;
-            }
-            ArrayList list = (ArrayList) m_monitors.clone();
-            list.remove( monitor );
-            if( list.size() == 0 )
-            {
-                m_monitors = null;
-            }
-            else
-            {
-                m_monitors = list;
-            }
+            super.addMonitor( monitor );
         }
     }
 }

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/ConnectionMonitorRouter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/ConnectionMonitorRouter.java
    (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/ConnectionMonitorRouter.java
    Tue Dec 14 17:53:53 2004
@@ -27,29 +27,33 @@
  * A commection monitor implemetation that routes connection notification 
requests
  * to registered listeners.
  */
-public class ConnectionMonitorRouter
+public class ConnectionMonitorRouter extends AbstractMonitorRouter
     implements ConnectionMonitor, Router
 {
-   /**
-    * List of attached monitors.
-    */
-    private ArrayList m_monitors;
-    
+    //--------------------------------------------------------------------
+    // constructors
+    //--------------------------------------------------------------------
+
+    public ConnectionMonitorRouter( Monitor trace )
+    {
+        super( trace );
+    }
+
+    //--------------------------------------------------------------------
+    // ConnectionMonitor
+    //--------------------------------------------------------------------
+
    /**
     * Notify registered monitors of a connection opened event.
     * @param url the target url
     */
     public void connectionOpened( URL url )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            ConnectionMonitor mon = (ConnectionMonitor) list.next();
-            mon.connectionOpened( url );
+            ConnectionMonitor monitor = (ConnectionMonitor) monitors[i];
+            monitor.connectionOpened( url );
         }
     }
     
@@ -59,15 +63,11 @@
     */
     public void connectStarted( URL url )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            ConnectionMonitor mon = (ConnectionMonitor) list.next();
-            mon.connectStarted( url );
+            ConnectionMonitor monitor = (ConnectionMonitor) monitors[i];
+            monitor.connectStarted( url );
         }
     }
     
@@ -77,15 +77,11 @@
     */
     public void connectCompleted( URL url )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            ConnectionMonitor mon = (ConnectionMonitor) list.next();
-            mon.connectCompleted( url );
+            ConnectionMonitor monitor = (ConnectionMonitor) monitors[i];
+            monitor.connectCompleted( url );
         }
     }
     
@@ -99,44 +95,9 @@
         {
             throw new IllegalArgumentException( "monitor must be 
ConnectionMonitor type." );
         }
-        synchronized( this )
-        {
-            ArrayList list;
-            if( m_monitors == null )
-            {
-                list = new ArrayList();
-            }
-            else
-            {
-                list = (ArrayList) m_monitors.clone();
-            }
-            list.add( monitor );
-            m_monitors = list;
-        }
-    }
-    
-   /**
-    * Remove a monitors from the set of registered monitors.
-    * @param monitor the monitor to remove
-    */
-    public void removeMonitor( Monitor monitor )
-    {
-        synchronized( this )
+        else
         {
-            if( m_monitors == null )
-            {
-                return;
-            }
-            ArrayList list = (ArrayList) m_monitors.clone();
-            list.remove( monitor );
-            if( list.size() == 0 )
-            {
-                m_monitors = null;
-            }
-            else
-            {
-                m_monitors = list;
-            }
+            super.addMonitor( monitor );
         }
     }
 }

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Monitor.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Monitor.java
    (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Monitor.java
    Tue Dec 14 17:53:53 2004
@@ -23,5 +23,17 @@
  */ 
 public interface Monitor
 {
+    /**
+     * Test is trace monitoring is enabled.
+     * @return true if debug trace messages are enabled elese false
+     */
+     boolean isTraceEnabled();
+
+    /**
+     * Notify the monitor of a trace level message to log.
+     *
+     * @param message the trace level message
+     */
+     void trace( String message );
 }
  

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/NetworkMonitorRouter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/NetworkMonitorRouter.java
       (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/NetworkMonitorRouter.java
       Tue Dec 14 17:53:53 2004
@@ -26,13 +26,21 @@
 /**
  * A router that handles multicasr distribution of monitor events to 
registered monitors.
  */
-public class NetworkMonitorRouter
+public class NetworkMonitorRouter extends AbstractMonitorRouter
     implements NetworkMonitor, Router
 {
-   /**
-    * List of monitors.
-    */
-    private ArrayList m_monitors;
+    //--------------------------------------------------------------------
+    // constructors
+    //--------------------------------------------------------------------
+
+    public NetworkMonitorRouter( Monitor trace )
+    {
+        super( trace );
+    }
+
+    //--------------------------------------------------------------------
+    // NetworkMonitor
+    //--------------------------------------------------------------------
 
    /**
     * Notify all subscribing monitors of a updated event.
@@ -42,15 +50,11 @@
     */
     public void notifyUpdate( URL resource, int expected, int count )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            NetworkMonitor mon = (NetworkMonitor) list.next();
-            mon.notifyUpdate( resource, expected, count );
+            NetworkMonitor monitor = (NetworkMonitor) monitors[i];
+            monitor.notifyUpdate( resource, expected, count );
         }
     }
 
@@ -60,15 +64,11 @@
     */
     public void notifyCompletion( URL resource )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            NetworkMonitor mon = (NetworkMonitor) list.next();
-            mon.notifyCompletion( resource );
+            NetworkMonitor monitor = (NetworkMonitor) monitors[i];
+            monitor.notifyCompletion( resource );
         }
     }
 
@@ -83,44 +83,9 @@
         {
             throw new IllegalArgumentException( "monitor must be 
NetworkMonitor type." );
         }
-        synchronized( this )
-        {
-            ArrayList list;
-            if( m_monitors == null )
-            {
-                list = new ArrayList();
-            }
-            else
-            {
-                list = (ArrayList) m_monitors.clone();
-            }
-            list.add( monitor );
-            m_monitors = list;
-        }
-    }
-
-   /**
-    * Remove the supplied monitor from the list of registered monitors.
-    * @param monitor the monitor to remove
-    */
-    public void removeMonitor( Monitor monitor )
-    {
-        synchronized( this )
+        else
         {
-            if( m_monitors == null )
-            {
-                return;
-            }
-            ArrayList list = (ArrayList) m_monitors.clone();
-            list.remove( monitor );
-            if( list.size() == 0 )
-            {
-                m_monitors = null;
-            }
-            else
-            {
-                m_monitors = list;
-            }
+            super.addMonitor( monitor );
         }
     }
 }

Added: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/NullMonitor.java
==============================================================================
--- (empty file)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/NullMonitor.java
        Tue Dec 14 17:53:53 2004
@@ -0,0 +1,43 @@
+/* 
+ * Copyright 2004 Niclas Hedhman.
+ *
+ * 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.monitors;
+ 
+/**
+ * A null monitor.
+ */
+public class NullMonitor implements Monitor
+{
+   /**
+    * Test is trace monitoring is enabled.
+    * @return true if debug trace messages are enabled elese false
+    */
+    public boolean isTraceEnabled()
+    {
+        return false;
+    }
+
+   /**
+    * Process a trace message.
+    *
+    * @param message the trace level message
+    */
+    public void trace( final String message )
+    {
+    }
+}

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/RepositoryMonitorRouter.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/RepositoryMonitorRouter.java
    (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/RepositoryMonitorRouter.java
    Tue Dec 14 17:53:53 2004
@@ -28,29 +28,33 @@
  * A repository monitor router handles mutlicast distribution of monitor 
events to 
  * a set of subscribed monitors.
  */
-public class RepositoryMonitorRouter
+public class RepositoryMonitorRouter extends AbstractMonitorRouter
     implements RepositoryMonitor, Router
-{
-   /**
-    * List of attached monitors.
-    */
-    private ArrayList m_monitors;
-   
+{   
+    //--------------------------------------------------------------------
+    // constructors
+    //--------------------------------------------------------------------
+
+    public RepositoryMonitorRouter( Monitor trace )
+    {
+        super( trace );
+    }
+
+    //--------------------------------------------------------------------
+    // RepositoryMonitor
+    //--------------------------------------------------------------------
+
    /**
     * Notify all subscribed monitors of a info message event.
     * @param info the information message
     */ 
     public void sequenceInfo( String info )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.sequenceInfo( info );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.sequenceInfo( info );
         }
     }
     
@@ -62,15 +66,11 @@
     */
     public void getPluginRequested( ClassLoader parent, URI uri, Object[] 
args )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.getPluginRequested( parent, uri, args );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.getPluginRequested( parent, uri, args );
         }
     }
     
@@ -80,15 +80,11 @@
     */
     public void establishedPluginClass( Class pluginClass )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.establishedPluginClass( pluginClass );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.establishedPluginClass( pluginClass );
         }
     }
     
@@ -99,15 +95,11 @@
     */
     public void exceptionOccurred( String methodname, Exception e )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.exceptionOccurred( methodname, e );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.exceptionOccurred( methodname, e );
         }
     }
     
@@ -118,15 +110,11 @@
     */
     public void pluginConstructorFound( Constructor constructor, Object[] 
args )
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.pluginConstructorFound( constructor, args );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.pluginConstructorFound( constructor, args );
         }
     }
     
@@ -136,15 +124,11 @@
     */
     public void pluginInstantiated( Object pluginInstance )
     {
-        if( m_monitors == null )
-        {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.pluginInstantiated( pluginInstance );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.pluginInstantiated( pluginInstance );
         }
     }
 
@@ -155,15 +139,11 @@
     */    
     public void classloaderConstructed( String type, ClassLoader classloader 
)
     {
-        if( m_monitors == null )
+        Monitor[] monitors = getMonitors();
+        for( int i=0; i < monitors.length; i++ )
         {
-            return;
-        }
-        Iterator list = m_monitors.iterator();
-        while( list.hasNext() )
-        {
-            RepositoryMonitor mon = (RepositoryMonitor) list.next();
-            mon.classloaderConstructed( type, classloader );
+            RepositoryMonitor monitor = (RepositoryMonitor) monitors[i];
+            monitor.classloaderConstructed( type, classloader );
         }
     }
 
@@ -179,46 +159,10 @@
         {
             throw new IllegalArgumentException( "monitor must be 
RepositoryMonitor type." );
         }
-        synchronized( this )
-        {
-            ArrayList list;
-            if( m_monitors == null )
-            {
-                list = new ArrayList();
-            }
-            else
-            {
-                list = (ArrayList) m_monitors.clone();
-            }
-            list.add( monitor );
-            m_monitors = list;
-        }
-    }
-    
-   /**
-    * Remove a monitor from the set of monitors managed by this router.
-    * @param monitor the monitor to remove
-    */
-    public void removeMonitor( Monitor monitor )
-    {
-        synchronized( this )
+        else
         {
-            if( m_monitors == null )
-            {
-                return;
-            }
-            ArrayList list = (ArrayList) m_monitors.clone();
-            list.remove( monitor );
-            if( list.size() == 0 )
-            {
-                m_monitors = null;
-            }
-            else
-            {
-                m_monitors = list;
-            }
+            super.addMonitor( monitor );
         }
     }
-
 }
  

Modified: 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Router.java
==============================================================================
--- 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Router.java
     (original)
+++ 
development/main/transit/handler/src/main/net/dpml/transit/monitors/Router.java
     Tue Dec 14 17:53:53 2004
@@ -35,5 +35,6 @@
     * @param monitor the monitor to remove
     */
     void removeMonitor( Monitor monitor );
+
 }