ARQMgt_X.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

package org.apache.jena.sparql.mgt ;

import java.lang.management.ManagementFactory ;
import java.util.HashMap ;
import java.util.Map ;

import javax.management.* ;

import org.apache.jena.atlas.lib.InternalErrorException ;
import org.apache.jena.atlas.logging.Log ;
import org.apache.jena.query.ARQ ;
import org.apache.jena.sparql.ARQException ;
import org.apache.jena.sparql.engine.QueryEngineBase ;
import org.slf4j.Logger ;
import org.slf4j.LoggerFactory ;

/* Old version of the class which did JMX operations.
 * See JENA-614 
 */
class ARQMgt_X {
    // In some environments, JMX does not exist.
    static private Logger                  log         = LoggerFactory.getLogger(ARQMgt_X.class) ;
    private static boolean                 initialized = false ;
    private static boolean                 noJMX       = false ;
    private static Map<ObjectName, Object> mgtObjects  = new HashMap<>() ;
    private static MBeanServer             mbs         = null ;

    public static synchronized void init() {
        if (initialized)
            return ;
        initialized = true ;
        if ( noJMX )
            return ;

        try {
            mbs = ManagementFactory.getPlatformMBeanServer() ;
        } catch (Throwable ex) {
            Log.debug(ARQMgt_X.class, "Failed to initialize JMX: "+ex.getMessage()) ;
            noJMX = true ;
            mbs = null ;
        }
    }
    
    public static void register() {
        init() ;
        String NS = ARQ.PATH ;
        ContextMBean cxtBean = new ContextMBean(ARQ.getContext()) ;
        QueryEngineInfo qeInfo = QueryEngineBase.queryEngineInfo ;
        // Done in ARQ initialization --
        // register(NS+".system:type=SystemInfo", ARQ.systemInfo) ;
        register(NS + ".system:type=Context", cxtBean) ;
        register(NS + ".system:type=Engine", qeInfo) ;
    }

    public static void register(String name, Object bean) {
        init() ;
        if (noJMX)
            return ;
        ObjectName objName = objectName(name) ;
        register(objName, bean) ;
    }

    public static void unregister(String name) {
        init() ;
        if (noJMX)
            return ;
        ObjectName objName = objectName(name) ;
        unregister(objName) ;
    }

    private static void register(ObjectName objName, Object bean) {
        try {
            // Unregister to avoid classloader problems.
            // A previous load of this class will have registered something
            // with the object name. Remove it - copes with reloading.
            // (Does not cope with multiple loads running in parallel.)
            if (mbs.isRegistered(objName)) {
                try {
                    mbs.unregisterMBean(objName) ;
                } catch (InstanceNotFoundException ex) {}
            }
            log.debug("Register MBean: " + objName) ;
            mbs.registerMBean(bean, objName) ;
            // remember ...
            mgtObjects.put(objName, bean) ;
        } catch (NotCompliantMBeanException ex) {
            log.warn("Failed to register (NotCompliantMBeanException)'" + objName.getCanonicalName() + "': " + ex.getMessage()) ;
            throw new ARQException("Failed to register '" + objName.getCanonicalName() + "': " + ex.getMessage(), ex) ;
        } catch (InstanceAlreadyExistsException ex) {
            log.warn("Failed to register (InstanceAlreadyExistsException)'" + objName.getCanonicalName() + "': " + ex.getMessage()) ;
            throw new ARQException("Failed to register '" + objName.getCanonicalName() + "': " + ex.getMessage(), ex) ;
        } catch (MBeanRegistrationException ex) {
            log.warn("Failed to register (MBeanRegistrationException)'" + objName.getCanonicalName() + "': " + ex.getMessage()) ;
            throw new ARQException("Failed to register '" + objName.getCanonicalName() + "': " + ex.getMessage(), ex) ;
        }
    }

    private static void unregister(ObjectName objName) {
        log.debug("Unregister MBean: " + objName) ;
        if ( ! mgtObjects.containsKey(objName) )
            log.warn("MBean not already registered: " + objName) ;
        try {
            mbs.unregisterMBean(objName) ;
        } 
        catch (InstanceNotFoundException ex) { }    // Meh, whatever
        catch (MBeanRegistrationException ex) {
            throw new InternalErrorException(ex) ;
        }
    }

    private static ObjectName objectName(String name) {
        try { return new ObjectName(name) ; }
        catch (MalformedObjectNameException ex) {
            throw new ARQException("Failed to create name '" + name + "': " + ex.getMessage(), ex) ;
        }
    }
}