public AppenderDynamicMBean(Appender appender) throws IntrospectionException 
{
        
    this.appender = appender;
    buildDynamicMBeanInfo();
}

 public Object getAttribute(String attributeName) throws ReflectionException, AttributeNotFoundException, MBeanException 
{
       // Check attributeName is not null to avoid NullPointerException later on
    if (attributeName == null) {
      throw new RuntimeOperationsException(new IllegalArgumentException(
			"Attribute name cannot be null"),
       "Cannot invoke a getter of " + dClassName + " with null attribute name");
    }
    cat.debug("getAttribute called with ["+attributeName+"].");
    if(attributeName.startsWith("appender="+appender.getName()+",layout")) {
      try {
	return new ObjectName("log4j:"+attributeName );
      } catch(Exception e) {
	cat.error("attributeName", e);
      }
    }
    MethodUnion mu = (MethodUnion) dynamicProps.get(attributeName);
    //cat.debug("----name="+attributeName+", b="+b);
    if(mu != null && mu.readMethod != null) {
      try {
	return mu.readMethod.invoke(appender, null);
      } catch(Exception e) {
	return null;
      }
    }
    // If attributeName has not been recognized throw an AttributeNotFoundException
    throw(new AttributeNotFoundException("Cannot find " + attributeName +
					 " attribute in " + dClassName));
}

 protected Logger getLogger() 
{
    return cat;
}

 public MBeanInfo getMBeanInfo() 
{
    cat.debug("getMBeanInfo called.");
    MBeanAttributeInfo[] attribs = new MBeanAttributeInfo[dAttributes.size()];
    dAttributes.toArray(attribs);
    return new MBeanInfo(dClassName,
			 dDescription,
			 attribs,
			 dConstructors,
			 dOperations,
			 new MBeanNotificationInfo[0]);
}

 public Object invoke(String operationName,
    Object[] params,
    String[] signature) throws ReflectionException, MBeanException 
{
    if(operationName.equals("activateOptions") &&
                     appender instanceof OptionHandler) {
      OptionHandler oh = (OptionHandler) appender;
      oh.activateOptions();
      return "Options activated.";
    } else if (operationName.equals("setLayout")) {
      Layout layout = (Layout) OptionConverter.instantiateByClassName((String)
								      params[0],
								      Layout.class,
								      null);
      appender.setLayout(layout);
      registerLayoutMBean(layout);
    }
    return null;
}

 public ObjectName preRegister(MBeanServer server,
    ObjectName name) 
{
    cat.debug("preRegister called. Server="+server+ ", name="+name);
    this.server = server;
    registerLayoutMBean(appender.getLayout());
    return name;
}

  void registerLayoutMBean(Layout layout) 
{
    if(layout == null)
      return;
    String name = appender.getName()+",layout="+layout.getClass().getName();
    cat.debug("Adding LayoutMBean:"+name);
    ObjectName objectName = null;
    try {
      LayoutDynamicMBean appenderMBean = new LayoutDynamicMBean(layout);
      objectName = new ObjectName("log4j:appender="+name);
      if (!server.isRegistered(objectName)) {
        server.registerMBean(appenderMBean, objectName);
        dAttributes.add(new MBeanAttributeInfo("appender=" + name, "javax.management.ObjectName",
                "The " + name + " layout.", true, true, false));
      }
    } catch(Exception e) {
      cat.error("Could not add DynamicLayoutMBean for ["+name+"].", e);
    }
}

 public  void setAttribute(Attribute attribute) throws InvalidAttributeValueException, ReflectionException, AttributeNotFoundException, MBeanException 
{
    // Check attribute is not null to avoid NullPointerException later on
    if (attribute == null) {
      throw new RuntimeOperationsException(
                  new IllegalArgumentException("Attribute cannot be null"),
		  "Cannot invoke a setter of " + dClassName +
		  " with null attribute");
    }
    String name = attribute.getName();
    Object value = attribute.getValue();
    if (name == null) {
      throw new RuntimeOperationsException(
                    new IllegalArgumentException("Attribute name cannot be null"),
		    "Cannot invoke the setter of "+dClassName+
		    " with null attribute name");
    }
    MethodUnion mu = (MethodUnion) dynamicProps.get(name);
    if(mu != null && mu.writeMethod != null) {
      Object[] o = new Object[1];
      Class[] params = mu.writeMethod.getParameterTypes();
      if(params[0] == org.apache.log4j.Priority.class) {
	value = OptionConverter.toLevel((String) value,
					(Level) getAttribute(name));
      }
      o[0] = value;
      try {
	mu.writeMethod.invoke(appender,  o);
      } catch(Exception e) {
	cat.error("FIXME", e);
      }
    } else if(name.endsWith(".layout")) {
    } else {
      throw(new AttributeNotFoundException("Attribute " + name +
					   " not found in " +
					   this.getClass().getName()));
    }
}