Simplified ManagedAttribute mechanism

examples/embedded/src/main/java/org/eclipse/jetty/embedded/LikeJettyXml.java

@@ -211,13 +211,11 @@ public class LikeJettyXml
         HashLoginService login = new HashLoginService();
         login.setName("Test Realm");
         login.setConfig(jetty_base + "/etc/realm.properties");
-        login.setRefreshInterval(0);
+        login.setHotReload(false);
         server.addBean(login);
         
-        
         // Start the server
         server.start();
-        server.dumpStdErr();
         server.join();
     }
 }

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java

@@ -112,9 +112,9 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     public final static int SERVLET_MAJOR_VERSION=3;
     public final static int SERVLET_MINOR_VERSION=1;
     public static final Class<?>[] SERVLET_LISTENER_TYPES = new Class[] {ServletContextListener.class,
-                                                                      ServletContextAttributeListener.class,
+        ServletContextAttributeListener.class,
-                                                                      ServletRequestListener.class,
+        ServletRequestListener.class,
-                                                                      ServletRequestAttributeListener.class};
+        ServletRequestAttributeListener.class};
 
     public static final int DEFAULT_LISTENER_TYPE_INDEX = 1;
     public static final int EXTENDED_LISTENER_TYPE_INDEX = 0;
@@ -155,7 +155,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         return null;
     }
 
-
     protected Context _scontext;
     private final AttributesMap _attributes;
     private final Map<String, String> _initParams;
@@ -760,22 +759,7 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     {
         String managedAttributes = _initParams.get(MANAGED_ATTRIBUTES);
         if (managedAttributes != null)
-        {
+            addEventListener(new ManagedAttributeListener(this,managedAttributes.split(",")));
-            _managedAttributes = new HashMap<String, Object>();
-            String[] attributes = managedAttributes.split(",");
-            for (String attribute : attributes)
-            {
-                _managedAttributes.put(attribute.trim(),null);
-            }
-
-            Enumeration<String> e = _scontext.getAttributeNames();
-            while (e.hasMoreElements())
-            {
-                String name = e.nextElement();
-                Object value = _scontext.getAttribute(name);
-                checkManagedAttribute(name,value);
-            }
-        }
 
         super.doStart();
 
@@ -845,13 +829,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             if (_errorHandler != null)
                 _errorHandler.stop();
 
-            Enumeration<String> e = _scontext.getAttributeNames();
-            while (e.hasMoreElements())
-            {
-                String name = e.nextElement();
-                checkManagedAttribute(name,null);
-            }
-
             for (EventListener l : _programmaticListeners)
                 removeEventListener(l);
             _programmaticListeners.clear();
@@ -993,8 +970,8 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         {
             // check the target.
             if (DispatcherType.REQUEST.equals(dispatch) ||
-                DispatcherType.ASYNC.equals(dispatch) ||
+                    DispatcherType.ASYNC.equals(dispatch) ||
-                DispatcherType.ERROR.equals(dispatch) && baseRequest.getHttpChannelState().isAsync())
+                    DispatcherType.ERROR.equals(dispatch) && baseRequest.getHttpChannelState().isAsync())
             {
                 if (_compactPath)
                     target = URIUtil.compactPath(target);
@@ -1247,7 +1224,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     @Override
     public void removeAttribute(String name)
     {
-        checkManagedAttribute(name,null);
         _attributes.removeAttribute(name);
     }
 
@@ -1261,7 +1237,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     @Override
     public void setAttribute( String name, Object value)
     {
-        checkManagedAttribute(name,value);
         _attributes.setAttribute(name,value);
     }
 
@@ -1274,36 +1249,15 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
     {
         _attributes.clearAttributes();
         _attributes.addAll(attributes);
-        Enumeration<String> e = _attributes.getAttributeNames();
-        while (e.hasMoreElements())
-        {
-            String name = e.nextElement();
-            checkManagedAttribute(name,attributes.getAttribute(name));
-        }
     }
 
     /* ------------------------------------------------------------ */
     @Override
     public void clearAttributes()
     {
-        Enumeration<String> e = _attributes.getAttributeNames();
-        while (e.hasMoreElements())
-        {
-            String name = e.nextElement();
-            checkManagedAttribute(name,null);
-        }
         _attributes.clearAttributes();
     }
 
-    /* ------------------------------------------------------------ */
-    public void checkManagedAttribute(String name, Object value)
-    {
-        if (_managedAttributes != null && _managedAttributes.containsKey(name))
-        {
-            setManagedAttribute(name,value);
-        }
-    }
-
     /* ------------------------------------------------------------ */
     public void setManagedAttribute(String name, Object value)
     {
@@ -2127,7 +2081,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         @Override
         public synchronized void setAttribute(String name, Object value)
         {
-            checkManagedAttribute(name,value);
             Object old_value = super.getAttribute(name);
 
             if (value == null)
@@ -2158,8 +2111,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
         @Override
         public synchronized void removeAttribute(String name)
         {
-            checkManagedAttribute(name,null);
-
             Object old_value = super.getAttribute(name);
             super.removeAttribute(name);
             if (old_value != null &&!_contextAttributeListeners.isEmpty())
@@ -2290,55 +2241,54 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
 
         public void setExtendedListenerTypes (boolean extended)
         {
-           _extendedListenerTypes = extended;
+            _extendedListenerTypes = extended;
         }
 
-       public boolean isExtendedListenerTypes()
+        public boolean isExtendedListenerTypes()
-       {
+        {
-           return _extendedListenerTypes;
+            return _extendedListenerTypes;
-       }
+        }
 
+        @Override
+        public ClassLoader getClassLoader()
+        {
+            if (!_enabled)
+                throw new UnsupportedOperationException();
 
-       @Override
+            //no security manager just return the classloader
-       public ClassLoader getClassLoader()
+            if (System.getSecurityManager() == null)
-       {
+                return _classLoader;
-           if (!_enabled)
+            else
-               throw new UnsupportedOperationException();
+            {
+                //check to see if the classloader of the caller is the same as the context
+                //classloader, or a parent of it
+                try
+                {
+                    Class<?> reflect = Loader.loadClass(getClass(), "sun.reflect.Reflection");
+                    Method getCallerClass = reflect.getMethod("getCallerClass", Integer.TYPE);
+                    Class<?> caller = (Class<?>)getCallerClass.invoke(null, 2);
 
-           //no security manager just return the classloader
+                    boolean ok = false;
-           if (System.getSecurityManager() == null)
+                    ClassLoader callerLoader = caller.getClassLoader();
-               return _classLoader;
+                    while (!ok && callerLoader != null)
-           else
+                    {
-           {
+                        if (callerLoader == _classLoader) 
-               //check to see if the classloader of the caller is the same as the context
+                            ok = true;
-               //classloader, or a parent of it
+                        else
-               try
+                            callerLoader = callerLoader.getParent();    
-               {
+                    }
-                   Class<?> reflect = Loader.loadClass(getClass(), "sun.reflect.Reflection");
-                   Method getCallerClass = reflect.getMethod("getCallerClass", Integer.TYPE);
-                   Class<?> caller = (Class<?>)getCallerClass.invoke(null, 2);
 
-                   boolean ok = false;
+                    if (ok)
-                   ClassLoader callerLoader = caller.getClassLoader();
+                        return _classLoader;
-                   while (!ok && callerLoader != null)
+                }
-                   {
+                catch (Exception e)      
-                       if (callerLoader == _classLoader) 
+                {
-                           ok = true;
+                    LOG.warn("Unable to check classloader of caller",e);
-                       else
+                }
-                           callerLoader = callerLoader.getParent();    
-                   }
 
-                   if (ok)
+                AccessController.checkPermission(new RuntimePermission("getClassLoader"));
-                       return _classLoader;
+                return _classLoader;
-               }
+            }
-               catch (Exception e)      
-               {
-                   LOG.warn("Unable to check classloader of caller",e);
-               }
-              
-               AccessController.checkPermission(new RuntimePermission("getClassLoader"));
-               return _classLoader;
-           }
         }
 
         @Override
@@ -2372,8 +2322,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             return _enabled;
         }
 
-
-
         public <T> T createInstance (Class<T> clazz) throws Exception
         {
             T o = clazz.newInstance();
@@ -2530,7 +2478,6 @@ public class ContextHandler extends ScopedHandler implements Attributes, Gracefu
             return null;
         }
 
-
         @Override
         public boolean setInitParameter(String name, String value)
         {

jetty-server/src/main/java/org/eclipse/jetty/server/handler/ManagedAttributeListener.java

@@ -0,0 +1,107 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.server.handler;
+
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.servlet.ServletContextAttributeEvent;
+import javax.servlet.ServletContextAttributeListener;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
+
+/* ------------------------------------------------------------ */
+/** Enable Jetty style JMX MBeans from within a Context 
+ */
+public class ManagedAttributeListener implements  ServletContextListener, ServletContextAttributeListener
+{
+    private static final Logger LOG = Log.getLogger(ManagedAttributeListener.class);
+
+    final Set<String> _managedAttributes=new HashSet<>();
+    final ContextHandler _context;
+    
+    public ManagedAttributeListener(ContextHandler context,String... managedAttributes)
+    {
+        _context=context;
+
+        for (String attr:managedAttributes)
+            _managedAttributes.add(attr);
+        
+        if (LOG.isDebugEnabled())
+            LOG.debug("managedAttributes {}",_managedAttributes);
+    }
+
+    @Override
+    public void attributeReplaced(ServletContextAttributeEvent event)
+    {
+        if (_managedAttributes.contains(event.getName()))
+            updateBean(event.getName(),event.getValue(),event.getServletContext().getAttribute(event.getName()));
+    }
+    
+    @Override
+    public void attributeRemoved(ServletContextAttributeEvent event)
+    {
+        if (_managedAttributes.contains(event.getName()))
+            updateBean(event.getName(),event.getValue(),null);                    
+    }
+    
+    @Override
+    public void attributeAdded(ServletContextAttributeEvent event)
+    {
+        if (_managedAttributes.contains(event.getName()))
+            updateBean(event.getName(),null,event.getValue());    
+    }
+
+    @Override
+    public void contextInitialized(ServletContextEvent event)
+    {                 
+        // Update existing attributes
+        Enumeration<String> e = event.getServletContext().getAttributeNames();
+        while (e.hasMoreElements())
+        {
+            String name = e.nextElement();
+            if (_managedAttributes.contains(name))
+                updateBean(name,null,event.getServletContext().getAttribute(name));
+        }
+    }
+    
+    @Override
+    public void contextDestroyed(ServletContextEvent event)
+    {
+        Enumeration<String> e = _context.getServletContext().getAttributeNames();
+        while (e.hasMoreElements())
+        {
+            String name = e.nextElement();
+            if (_managedAttributes.contains(name))
+                updateBean(name,event.getServletContext().getAttribute(name),null);
+        }
+    }
+    
+    protected void updateBean(String name,Object oldBean,Object newBean)
+    {
+        LOG.info("update {} {}->{} on {}",name,oldBean,newBean,_context);
+        if (LOG.isDebugEnabled())
+            LOG.debug("update {} {}->{} on {}",name,oldBean,newBean,_context);
+        _context.updateBean(oldBean,newBean,false);
+    }
+}