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Controlling ObjectName Instances for Your Beans

Behind the scenes, the MBeanExporter delegates to an implementation of the ObjectNamingStrategy to obtain an ObjectName instance for each of the beans it registers. By default, the default implementation, KeyNamingStrategy uses the key of the beans Map as the ObjectName. In addition, the KeyNamingStrategy can map the key of the beans Map to an entry in a Properties file (or files) to resolve the ObjectName. In addition to the KeyNamingStrategy, Spring provides two additional ObjectNamingStrategy implementations: the IdentityNamingStrategy (which builds an ObjectName based on the JVM identity of the bean) and the MetadataNamingStrategy (which uses source-level metadata to obtain the ObjectName).

Reading ObjectName Instances from Properties

You can configure your own KeyNamingStrategy instance and configure it to read ObjectName instances from a Properties instance rather than use a bean key. The KeyNamingStrategy tries to locate an entry in the Properties with a key that corresponds to the bean key. If no entry is found or if the Properties instance is null, the bean key itself is used.

The following code shows a sample configuration for the KeyNamingStrategy:

<beans>

	<bean id="exporter" class="org.springframework.jmx.export.MBeanExporter">
		<property name="beans">
			<map>
				<entry key="testBean" value-ref="testBean"/>
			</map>
		</property>
		<property name="namingStrategy" ref="namingStrategy"/>
	</bean>

	<bean id="testBean" class="org.springframework.jmx.JmxTestBean">
		<property name="name" value="TEST"/>
		<property name="age" value="100"/>
	</bean>

	<bean id="namingStrategy" class="org.springframework.jmx.export.naming.KeyNamingStrategy">
		<property name="mappings">
			<props>
				<prop key="testBean">bean:name=testBean1</prop>
			</props>
		</property>
		<property name="mappingLocations">
			<value>names1.properties,names2.properties</value>
		</property>
	</bean>

</beans>

The preceding example configures an instance of KeyNamingStrategy with a Properties instance that is merged from the Properties instance defined by the mapping property and the properties files located in the paths defined by the mappings property. In this configuration, the testBean bean is given an ObjectName of bean:name=testBean1, since this is the entry in the Properties instance that has a key corresponding to the bean key.

If no entry in the Properties instance can be found, the bean key name is used as the ObjectName.

Using MetadataNamingStrategy

MetadataNamingStrategy uses the objectName property of the ManagedResource attribute on each bean to create the ObjectName. The following code shows the configuration for the MetadataNamingStrategy:

<beans>

	<bean id="exporter" class="org.springframework.jmx.export.MBeanExporter">
		<property name="beans">
			<map>
				<entry key="testBean" value-ref="testBean"/>
			</map>
		</property>
		<property name="namingStrategy" ref="namingStrategy"/>
	</bean>

	<bean id="testBean" class="org.springframework.jmx.JmxTestBean">
		<property name="name" value="TEST"/>
		<property name="age" value="100"/>
	</bean>

	<bean id="namingStrategy" class="org.springframework.jmx.export.naming.MetadataNamingStrategy">
		<property name="attributeSource" ref="attributeSource"/>
	</bean>

	<bean id="attributeSource"
			class="org.springframework.jmx.export.annotation.AnnotationJmxAttributeSource"/>

</beans>

If no objectName has been provided for the ManagedResource attribute, an ObjectName is created with the following format: [fully-qualified-package-name]:type=[short-classname],name=[bean-name]. For example, the generated ObjectName for the following bean would be com.example:type=MyClass,name=myBean:

<bean id="myBean" class="com.example.MyClass"/>

Configuring Annotation-based MBean Export

If you prefer to use the annotation-based approach to define your management interfaces, a convenience subclass of MBeanExporter is available: AnnotationMBeanExporter. When defining an instance of this subclass, you no longer need the namingStrategy, assembler, and attributeSource configuration, since it always uses standard Java annotation-based metadata (autodetection is always enabled as well). In fact, rather than defining an MBeanExporter bean, an even simpler syntax is supported by the @EnableMBeanExport @Configuration annotation, as the following example shows:

@Configuration
@EnableMBeanExport
public class AppConfig {

}

If you prefer XML-based configuration, the <context:mbean-export/> element serves the same purpose and is shown in the following listing:

<context:mbean-export/>

If necessary, you can provide a reference to a particular MBean server, and the defaultDomain attribute (a property of AnnotationMBeanExporter) accepts an alternate value for the generated MBean ObjectName domains. This is used in place of the fully qualified package name as described in the previous section on MetadataNamingStrategy, as the following example shows:

@EnableMBeanExport(server="myMBeanServer", defaultDomain="myDomain")
@Configuration
ContextConfiguration {

}

The following example shows the XML equivalent of the preceding annotation-based example:

<context:mbean-export server="myMBeanServer" default-domain="myDomain"/>
Do not use interface-based AOP proxies in combination with autodetection of JMX annotations in your bean classes. Interface-based proxies “hide” the target class, which also hides the JMX-managed resource annotations. Hence, you should use target-class proxies in that case (through setting the 'proxy-target-class' flag on <aop:config/>, <tx:annotation-driven/> and so on). Otherwise, your JMX beans might be silently ignored at startup.