/**
 * 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.
 */
/**
 * gnodet: this file mainly contains a modification in the mbean
 * registration so that they belong to org.apache.hadoop to be
 * more consistent with our other mbeans
 */
package org.apache.hadoop.metrics2.util;

import java.lang.management.ManagementFactory;

import javax.management.InstanceNotFoundException;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.InstanceAlreadyExistsException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;


/**
 * This util class provides a method to register an MBean using
 * our standard naming convention as described in the doc
 *  for {link {@link #register(String, String, Object)}
 *
 */
public class MBeans {

    private static final Log LOG = LogFactory.getLog(MBeans.class);

    /**
     * Register the MBean using our standard MBeanName format
     * "hadoop:service=<serviceName>,name=<nameName>"
     * Where the <serviceName> and <nameName> are the supplied parameters
     *
     * @param serviceName
     * @param nameName
     * @param theMbean - the MBean to register
     * @return the named used to register the MBean
     */
    static public ObjectName register(String serviceName, String nameName,
                                      Object theMbean) {
        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        ObjectName name = getMBeanName(serviceName, nameName);
        try {
            mbs.registerMBean(theMbean, name);
            return name;
        } catch (InstanceAlreadyExistsException ie) {
            LOG.warn(name, ie);
        } catch (Exception e) {
            LOG.warn("Error registering "+ name, e);
        }
        return null;
    }

    static public void unregister(ObjectName mbeanName) {
        final MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        if (mbeanName == null)
            return;
        try {
            mbs.unregisterMBean(mbeanName);
        } catch (InstanceNotFoundException e ) {
            LOG.warn(mbeanName, e);
        } catch (Exception e) {
            LOG.warn("Error unregistering "+ mbeanName, e);
        }
    }

    static private ObjectName getMBeanName(String serviceName, String nameName) {
        ObjectName name = null;
        String nameStr = "org.apache.hadoop:service="+ serviceName +",name="+ nameName;
        try {
            name = new ObjectName(nameStr);
        } catch (MalformedObjectNameException e) {
            LOG.warn("Error creating MBean object name: "+ nameStr, e);
        }
        return name;
    }
}