org.jolokia.support.jmx.JolokiaMBeanServerUtil Maven / Gradle / Ivy
package org.jolokia.support.jmx;
/*
* Copyright 2009-2013 Roland Huss
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import java.lang.management.ManagementFactory;
import javax.management.*;
import org.jolokia.server.core.service.serializer.Serializer;
/**
* Utility class for looking up the Jolokia-internal MBeanServer which never gets exposed via JSR-160
*
* @author roland
* @since 13.01.13
*/
public final class JolokiaMBeanServerUtil {
// Only static methods
private JolokiaMBeanServerUtil() {
}
/**
* Lookup the JolokiaMBean server via a JMX lookup to the Jolokia-internal MBean exposing this MBeanServer.
* Note if this method is used in an OSGi environment, it will only return non-null if a Jolokia {@link Serializer}
* is registered as a service. So, it can return null e.g. during startup of an OSGi container. The
* client must deal with a null-return value and wait until this bundle
* has been started. After this, a service tracker is used as a proxy for the serializer service, which, when called
* without an registered serializer service will throw an exception.
*
* If used in a non-OSGi environment and the class "org.jolokia.service.serailizer.JolokiaSerializer" is on the classpath,
* this method will return the requested MBeanServer, (always) null otherwise .
*
* @return the Jolokia MBeanServer or null if not yet available present
*/
public static MBeanServer getJolokiaMBeanServer() {
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
MBeanServer jolokiaMBeanServer = null;
try {
jolokiaMBeanServer =
(MBeanServer) server.getAttribute(JolokiaMBeanServerHolder.MBEAN_SERVER_HOLDER_OBJECTNAME,
JolokiaMBeanServerHolderMBean.JOLOKIA_MBEAN_SERVER_ATTRIBUTE);
} catch (InstanceNotFoundException exp) {
// should be probably locked, but for simplicity reasons and because
// the probability of a clash is fairly low (can happen only once), it's omitted
// here. Note, that server.getAttribute() itself is threadsafe.
Serializer serializer = lookupSerializer();
if (serializer != null) {
jolokiaMBeanServer = JolokiaMBeanServerHolder.registerJolokiaMBeanServerHolderMBean(server, serializer);
}
} catch (JMException e) {
throw new IllegalStateException("Internal: Cannot get JolokiaMBean server via JMX lookup: " + e,e);
}
return jolokiaMBeanServer;
}
/**
* Register an MBean at the JolokiaMBeanServer. This call is directly delegated
* to the JolokiaMBeanServer
*
* @param object object to register
* @param name object name under which to register the MBean
* @return the object instance created
* @throws InstanceAlreadyExistsException
* @throws MBeanRegistrationException
* @throws NotCompliantMBeanException
*/
public static ObjectInstance registerMBean(Object object, ObjectName name) throws InstanceAlreadyExistsException, MBeanRegistrationException, NotCompliantMBeanException {
return getJolokiaMBeanServer().registerMBean(object, name);
}
/**
* Unregister an MBean at the JolokiaMBeanServer. This call is directly delegated
* to the JolokiaMBeanServer
*
* @param name objectname of the MBean to unregister
* @throws InstanceNotFoundException
* @throws MBeanRegistrationException
*/
public static void unregisterMBean(ObjectName name) throws InstanceNotFoundException, MBeanRegistrationException {
getJolokiaMBeanServer().unregisterMBean(name);
}
// If used via this method, only the Jolokia serializer is used. If used via OSGi, any serializer registered
// as a service is used.
private static Serializer lookupSerializer() {
try {
Class clazz = Class.forName("org.jolokia.service.serializer.JolokiaSerializer");
return (Serializer) clazz.newInstance();
} catch (ClassNotFoundException e) {
// No serializer available
return null;
} catch (InstantiationException e) {
// No serializer available
return null;
} catch (IllegalAccessException e) {
// No serializer available
return null;
}
}
}