package com.onaro.sanscreen.client.jmxframework;

import java.lang.management.ManagementFactory;

import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;

/**
 * Contains generic functionalities for MBean services like: 
 * <ul>
 * <li> Object Name creation
 * <li> Registraction and Unregister with the MBean Server
 * <li> Call backs to the service implemention class
 * </ul>   
 * 
 * @since 05/01/2008
 * @author john.cohen
 */
public abstract class FrameworkService implements FrameworkServiceMBean {
    /**
     * Name of SANscreen JMX service
     */
    public static final String CLIENT_JMX_DOMAIN_NAME = "SANscreen GUI"; //$NON-NLS-1$
    /**
     * Name of JMX property holding the service name
     */
    public static final String CLIENT_JMX_SERVICE_NAME_PROPERTY = "name"; //$NON-NLS-1$

    private static final Logger logger = LogManager.getLogger(FrameworkService.class);
	private final String serviceName;
	private final ObjectName objectName;

	/**
	 * Constructor.
	 *  
	 * @param serviceName name of the service that is going to be exposes by MBean.
	 */
	public FrameworkService(final String serviceName){
		this.serviceName = serviceName;
		objectName = createObjectName();
	}
	
	public String getServiceName() {
		return serviceName;
	}

	public void start() {
		// Call back to the implementation class, for additional actions.
        doStart();

        // Registers the MBean 
        registerMBean(this, objectName);
	}

	public void stop() {
		// Call back to the implementation class, for additional actions.
		doStop();

		// Registers the MBean
		unregisterMBean(objectName);
	}
	
    private ObjectName createObjectName() {
        try {
            return new ObjectName(CLIENT_JMX_DOMAIN_NAME, CLIENT_JMX_SERVICE_NAME_PROPERTY, getServiceName());
        }
        catch (MalformedObjectNameException e) {
            logger.error(e.getMessage(), e);
            return null;
        }		
    }

    
    private void registerMBean(final Object implementation, final ObjectName objectName) {
        // Unregister any left overs for this MBean (this is usefull only when testing)
        if (ManagementFactory.getPlatformMBeanServer().isRegistered(objectName)) 
        	unregisterMBean(objectName);

        try {
            ManagementFactory.getPlatformMBeanServer().registerMBean(implementation, objectName);

            if (logger.isDebugEnabled())
                logger.debug(getServiceName() + " - Registered MBean as " + getServiceName()); //$NON-NLS-1$
        }
        catch (Exception e) {
            logger.error("Failed to register MBean for " + getServiceName(), e); //$NON-NLS-1$
        }
    }
    
    private void unregisterMBean(final ObjectName objectName) {
        try {
            ManagementFactory.getPlatformMBeanServer().unregisterMBean(objectName);

            if (logger.isDebugEnabled())
                logger.debug(getServiceName() + " - Unregistered MBean " + getServiceName()); //$NON-NLS-1$
        }
        catch (Exception e) {
            logger.error("Failed to unregister MBean for " + getServiceName(), e); //$NON-NLS-1$
        }
    }

    /**
     * Call back method intendent to be overriden by the implementing class.
     */
    public abstract void doStart();
    
    /**
     * Call back method intendent to be overriden by the implementing class. 
     */
	public abstract void doStop();

}