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8.5.2. JMX-Based Deployment in JBoss AS (JBoss AS 5.x and 4.x)

If PojoCache is run in JBoss AS then your cache can be deployed as an MBean simply by copying a standard cache configuration file to the server's deploy directory. The standard format of PojoCache's standard XML configuration file (as shown in the Appendix) is the same as a JBoss AS MBean deployment descriptor, so the AS's SAR Deployer has no trouble handling it. Also, you don't have to place the configuration file directly in deploy; you can package it along with other services or JEE components in a SAR or EAR.

In AS 5, if you're using a server config based on the standard all config, then that's all you need to do; all required jars will be on the classpath. Otherwise, you will need to ensure pojocache.jar, jbosscache.jar and jgroups-all.jar are on the classpath. You may need to add other jars if you're using things like JdbmCacheLoader. The simplest way to do this is to copy the jars from the PojoCache distribution's lib directory to the server config's lib directory. You could also package the jars with the configuration file in Service Archive (.sar) file or an EAR.

It is possible, to deploy a POJO Cache 2.0 instance in JBoss AS 4.x However, the significant API changes between the 2.x and 1.x releases mean none of the standard AS 4.x clustering services (e.g. http session replication) that rely on the 1.x API will work with PojoCache 2.x. Also, be aware that usage of PojoCache 2.x in AS 4.x is not something the cache developers are making any significant effort to test, so be sure to test your application well (which of course you're doing anyway.)

Note in the example the value of the mbean element's code attribute: org.jboss.cache.pojo.jmx.PojoCacheJmxWrapper. This is the class JBoss Cache uses to handle JMX integration; the PojoCache itself does not expose an MBean interface. See the JBoss Cache MBeans section for more on the PojoCacheJmxWrapper.

Once your cache is deployed, in order to use it with an in-VM client such as a servlet, a JMX proxy can be used to get a reference to the cache:

MBeanServer server = MBeanServerLocator.locateJBoss();
	ObjectName on = new ObjectName("jboss.cache:service=PojoCache");
	PojoCacheJmxWrapperMBean cacheWrapper =
	(PojoCacheJmxWrapperMBean) MBeanServerInvocationHandler.newProxyInstance(server, on,
	PojoCacheJmxWrapperMBean.class, false);
	PojoCache cache = cacheWrapper.getPojoCache();

The MBeanServerLocator class is a helper to find the (only) JBoss MBean server inside the current JVM. The javax.management.MBeanServerInvocationHandler class' newProxyInstance method creates a dynamic proxy implementing the given interface and uses JMX to dynamically dispatch methods invoked against the generated interface to the MBean. The name used to look up the MBean is the same as defined in the cache's configuration file.

Once the proxy to the PojoCacheJmxWrapper is obtained, the getPojoCache() will return a reference to the PojoCache itself.