/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2010, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.jboss.as.jmx;

import static org.jboss.as.jmx.JmxLogger.ROOT_LOGGER;
import static org.jboss.as.jmx.JmxMessages.MESSAGES;

import java.lang.management.ManagementFactory;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import org.jboss.msc.inject.Injector;
import org.jboss.msc.service.Service;
import org.jboss.msc.service.ServiceName;
import org.jboss.msc.service.StartContext;
import org.jboss.msc.service.StartException;
import org.jboss.msc.service.StopContext;
import org.jboss.msc.value.InjectedValue;
import org.jboss.msc.value.Value;

/**
 * Service used to register and unregister an mbean with an mbean server.
 *
 * @author John Bailey
 */
public class MBeanRegistrationService<T> implements Service<Void> {
    public static final ServiceName SERVICE_NAME = ServiceName.JBOSS.append("mbean", "registration");
    private final InjectedValue<MBeanServer> injectedMBeanServer = new InjectedValue<MBeanServer>();
    private final InjectedValue<T> value = new InjectedValue<T>();
    private final String name;
    private ObjectName objectName;

    /**
     * Create an instance.
     *
     * @param name The name to use as an ObjectName
     */
    public MBeanRegistrationService(final String name) {
        this.name = name;
    }

    /**
     * Create an instance.
     *
     * @param name The name to use as an ObjectName
     * @param value The object to register
     */
    public MBeanRegistrationService(final String name, final Value<T> value) {
        this.name = name;
        this.value.inject(value.getValue());
    }

    /**
     * Register the mbean with the mbean server.
     *
     * @param context The start context
     * @throws StartException If any registration problems occur
     */
    public synchronized void start(final StartContext context) throws StartException {
        final MBeanServer mBeanServer = getMBeanServer();
        final T value = this.value.getValue();
        try {
            objectName = new ObjectName(name);
        } catch (MalformedObjectNameException e) {
            throw MESSAGES.mbeanRegistrationFailed(e, name);
        }

        try {
            ROOT_LOGGER.debugf("Registering [%s] with name [%s]", value, objectName);
            mBeanServer.registerMBean(value, objectName);
        } catch (Exception e) {
            throw MESSAGES.mbeanRegistrationFailed(e, name);
        }
    }

    /**
     * Unregister the mbean from the mbean server.
     *
     * @param context The stop context
     */
    public synchronized void stop(StopContext context) {
        if(objectName == null){
            ROOT_LOGGER.cannotUnregisterObject();
        }
        final MBeanServer mBeanServer = getMBeanServer();
        try {
            mBeanServer.unregisterMBean(objectName);
        } catch (Exception e) {
            ROOT_LOGGER.unregistrationFailure(e, objectName);
        }
    }

    /** {@inheritDoc} */
    public Void getValue() throws IllegalStateException {
        return null;
    }

    public Injector<MBeanServer> getMBeanServerInjector() {
        return injectedMBeanServer;
    }

    public Injector<T> getValueInjector() {
        return value;
    }

    private MBeanServer getMBeanServer() {
        MBeanServer mBeanServer = injectedMBeanServer.getOptionalValue();
        if(mBeanServer == null) {
            mBeanServer = ManagementFactory.getPlatformMBeanServer();
        }
        return mBeanServer;
    }
}
