package org.jolokia.backend;
/*
* 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.util.UUID;
import javax.management.*;
import org.jolokia.backend.executor.NotChangedException;
import org.jolokia.config.ConfigKey;
import org.jolokia.config.Configuration;
import org.jolokia.converter.Converters;
import org.jolokia.detector.ServerHandle;
import org.jolokia.discovery.JolokiaDiscovery;
import org.jolokia.discovery.JolokiaDiscoveryMBean;
import org.jolokia.handler.JsonRequestHandler;
import org.jolokia.handler.RequestHandlerManager;
import org.jolokia.history.HistoryStore;
import org.jolokia.request.JmxRequest;
import org.jolokia.restrictor.Restrictor;
import org.jolokia.util.DebugStore;
import org.jolokia.util.LogHandler;
/**
* Dispatcher which dispatches to one or more local {@link javax.management.MBeanServer}.
*
* @author roland
* @since Nov 11, 2009
*/
public class LocalRequestDispatcher implements RequestDispatcher {
// Agent ID
private final String agentId;
// Handler for finding and merging the various MBeanHandler
private MBeanServerHandler mBeanServerHandler;
private RequestHandlerManager requestHandlerManager;
// An (optional) qualifier for registering MBeans.
private String qualifier;
// Logger
private LogHandler log;
/**
* Create a new local dispatcher which accesses local MBeans.
*
* @param pConverters object/string converters
* @param pRestrictor restrictor which checks the access for various operations
* @param pConfig agent configuration
* @param pLogHandler local handler used for logging out errors and warnings
*/
public LocalRequestDispatcher(Converters pConverters, Restrictor pRestrictor, Configuration pConfig, LogHandler pLogHandler) {
// Get all MBean servers we can find. This is done by a dedicated
// handler object
mBeanServerHandler = new MBeanServerHandler(pConfig,pLogHandler);
qualifier = pConfig.get(ConfigKey.MBEAN_QUALIFIER);
log = pLogHandler;
agentId = pConfig.get(ConfigKey.AGENT_ID);
// Request handling manager
requestHandlerManager =
new RequestHandlerManager(pConfig,pConverters,mBeanServerHandler.getServerHandle(),pRestrictor);
}
// Can handle any request
/** {@inheritDoc} */
public boolean canHandle(JmxRequest pJmxRequest) {
return true;
}
/** {@inheritDoc} */
public boolean useReturnValueWithPath(JmxRequest pJmxRequest) {
JsonRequestHandler handler = requestHandlerManager.getRequestHandler(pJmxRequest.getType());
return handler.useReturnValueWithPath();
}
/** {@inheritDoc} */
public Object dispatchRequest(JmxRequest pJmxReq)
throws InstanceNotFoundException, AttributeNotFoundException, ReflectionException, MBeanException, NotChangedException {
JsonRequestHandler handler = requestHandlerManager.getRequestHandler(pJmxReq.getType());
return mBeanServerHandler.dispatchRequest(handler, pJmxReq);
}
/**
* Initialise this request dispatcher, which will register a {@link ConfigMBean} for easy external
* access to the {@link HistoryStore} and {@link DebugStore}. Also a {@link JolokiaDiscoveryMBean}
* is registered
*
* @param pHistoryStore history store to be managed from within an MBean
* @param pDebugStore managed debug store
* @throws MalformedObjectNameException if our MBean's name is wrong (which cannot happen)
* @throws MBeanRegistrationException if registration fails
* @throws NotCompliantMBeanException if we have a non compliant MBean (cannot happen, too)
*/
public void initMBeans(HistoryStore pHistoryStore, DebugStore pDebugStore)
throws MalformedObjectNameException, MBeanRegistrationException, NotCompliantMBeanException {
// Register the Config MBean
String oName = createObjectNameWithQualifier(Config.OBJECT_NAME);
try {
Config config = new Config(pHistoryStore,pDebugStore,oName);
mBeanServerHandler.registerMBean(config,oName);
} catch (InstanceAlreadyExistsException exp) {
String alternativeOName = oName + ",uuid=" + UUID.randomUUID();
try {
// Another instance has already started a Jolokia agent within the JVM. We are trying to add the MBean nevertheless with
// a dynamically generated ObjectName. Of course, it would be good to have a more semantic meaning instead of
// a random number, but this can already be performed with a qualifier
log.info(oName + " is already registered. Adding it with " + alternativeOName + ", but you should revise your setup in " +
"order to either use a qualifier or ensure, that only a single agent gets registered (otherwise history functionality might not work)");
Config config = new Config(pHistoryStore,pDebugStore,alternativeOName);
mBeanServerHandler.registerMBean(config,alternativeOName);
} catch (InstanceAlreadyExistsException e) {
log.error("Cannot even register fallback MBean with name " + alternativeOName + ". Should never happen. Really.",e);
}
}
// Register another Config MBean (which dispatched to the stores anyway) for access by
// jmx4perl version < 0.80
String legacyOName = createObjectNameWithQualifier(Config.LEGACY_OBJECT_NAME);
try {
Config legacyConfig = new Config(pHistoryStore,pDebugStore,legacyOName);
mBeanServerHandler.registerMBean(legacyConfig,legacyOName);
} catch (InstanceAlreadyExistsException exp) {
log.info("Cannot register (legacy) MBean handler for config store with name " + legacyOName + " since it already exists. " +
"This is the case if another agent has been already started within the same JVM. The registration is skipped.");
}
try {
mBeanServerHandler.registerMBean(new JolokiaDiscovery(agentId,log),JolokiaDiscoveryMBean.OBJECT_NAME);
} catch (InstanceAlreadyExistsException e) {
// Ignore since there is already one registered.
log.info("Jolokia Discovery MBean registration is skipped because there is already one registered.");
}
}
/**
* Unregister the config MBean
*
* @throws JMException if unregistration fails
*/
public void destroy() throws JMException {
mBeanServerHandler.destroy();
}
/**
* Get information about the current server
* @return the server information
*/
public ServerHandle getServerHandle() {
return mBeanServerHandler.getServerHandle();
}
private String createObjectNameWithQualifier(String pOName) {
return pOName + (qualifier != null ? "," + qualifier : "");
}
}