com.kdgregory.log4j.aws

Class StatisticsMBean

java.lang.Object

com.kdgregory.log4j.aws.StatisticsMBean

All Implemented Interfaces:

DynamicMBean, MBeanRegistration

public class StatisticsMBean
extends Object
implements DynamicMBean, MBeanRegistration

This class provides a bridge between an appenders and an MBeanServer. When an instance of this class has been registered, it will in turn register all appenders loaded by the same classloader hierarchy.

Example

      ManagementFactory.getPlatformMBeanServer().createMBean(
              HierarchyDynamicMBean.class.getName(),
              new ObjectName("log4j:name=Config"));

      ManagementFactory.getPlatformMBeanServer().createMBean(
              StatisticsMBean.class.getName(),
              new ObjectName("log4j:name=StatisticsEnabled"));
  

Note that the object names for both beans can be whatever you want. The names that I show here are consistent with the hardcoded names produced by both the Log4J appender/layout beans and the appender statistics beans from this package, so if you use them you'll see everything Log4J in one place.

Support for multiple Log4J hierarchies

For a stand-alone application, you would typically register both the Log4J HierarchyDynamicMBean and this bean with the platform MBean server. For a multi-container deployment such as an app-server, however, you may have a container-specific MBean server. However, there's no simple way to identify which of possibly many MBean servers may be the one we use to register, or if indeed we should register.

The solution I've chosen is to maintain two static collections: one holds registrations for instances of this class, the other holds references to each of the configured appenders. When one or the other of these collections changes then the appropriate JMX registrations/deregistrations are performed.

If you never register an instance of this class, then JMX is effectively disabled.

Constructor Summary

Constructors

Constructor and Description
StatisticsMBean()

Method Summary

Modifier and Type	Method and Description
Object	getAttribute(String attribute)
AttributeList	getAttributes(String[] attributes)
MBeanInfo	getMBeanInfo()
Object	invoke(String actionName, Object[] params, String[] signature)
void	postDeregister()
void	postRegister(Boolean registrationDone)
void	preDeregister()
ObjectName	preRegister(MBeanServer server, ObjectName name)
void	setAttribute(Attribute attribute)
AttributeList	setAttributes(AttributeList attributes)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StatisticsMBean

public StatisticsMBean()

Method Detail

getAttribute

public Object getAttribute(String attribute)
                    throws AttributeNotFoundException,
                           MBeanException,
                           ReflectionException

Specified by:

getAttribute in interface DynamicMBean

Throws:

AttributeNotFoundException

MBeanException

ReflectionException

setAttribute

public void setAttribute(Attribute attribute)
                  throws AttributeNotFoundException,
                         InvalidAttributeValueException,
                         MBeanException,
                         ReflectionException

Specified by:

setAttribute in interface DynamicMBean

Throws:

AttributeNotFoundException

InvalidAttributeValueException

MBeanException

ReflectionException

getAttributes

public AttributeList getAttributes(String[] attributes)

Specified by:

getAttributes in interface DynamicMBean

setAttributes

public AttributeList setAttributes(AttributeList attributes)

Specified by:

setAttributes in interface DynamicMBean

invoke

public Object invoke(String actionName,
                     Object[] params,
                     String[] signature)
              throws MBeanException,
                     ReflectionException

Specified by:

invoke in interface DynamicMBean

Throws:

MBeanException

ReflectionException

getMBeanInfo

public MBeanInfo getMBeanInfo()

Specified by:

getMBeanInfo in interface DynamicMBean

preRegister

public ObjectName preRegister(MBeanServer server,
                              ObjectName name)
                       throws Exception

Specified by:

preRegister in interface MBeanRegistration

Throws:

Exception

postRegister

public void postRegister(Boolean registrationDone)

Specified by:

postRegister in interface MBeanRegistration

preDeregister

public void preDeregister()
                   throws Exception

Specified by:

preDeregister in interface MBeanRegistration

Throws:

Exception

postDeregister

public void postDeregister()

Specified by:

postDeregister in interface MBeanRegistration