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package com.sun.enterprise.management.support;

import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.HashMap;
import java.util.Collections;

import javax.management.Notification;
import javax.management.MBeanNotificationInfo;


import com.sun.appserv.management.base.AMX;
import com.sun.appserv.management.base.NotificationEmitterService;

import com.sun.appserv.management.util.misc.GSetUtil;
import com.sun.appserv.management.util.jmx.JMXUtil;



/**
	A key aspect of the implementation is that it maintains a list of all types
	of Notifications it has seen emitted, paired with the implementing class
	so that getNotificationInfo() can return infos that accurately reflect
	what it is likely to emit.  This approach is used instead of statically
	coding Notification classes/types because it cannot be known in advance
	which type(s) will actually be emitted.
 */
public final class NotificationEmitterServiceImpl extends AMXImplBase
	implements NotificationEmitterService
{
	/**
		Each class of Notification may have one or more types associated with it,
		stored in a Set<String>:<br>
		Map<notif classname, Set<String of notif type>>
	 */
	private final Map<String,Set<String>>	mEmittedTypes;
	
		public
	NotificationEmitterServiceImpl( )
	{
		mEmittedTypes	= Collections.synchronizedMap( new HashMap<String,Set<String>>() );
	}

		public String
	getGroup()
	{
		return( AMX.GROUP_UTILITY );
	}
	
		public boolean
	getMBeanInfoIsInvariant()
	{
		return( false );	// MBeanNotificationInfo may grow as we learn of new types
	}
	
	
		public MBeanNotificationInfo[]
	getNotificationInfo()
	{
		final MBeanNotificationInfo[]	superTypes	= super.getNotificationInfo();
		
		final Set<MBeanNotificationInfo>	dynamicInfos	=
		    new HashSet<MBeanNotificationInfo>();
		
		/*
			Go through our list of class/types we've seen emitted so far
			and generate MBeanNotificationInfo for each class of Notification
		 */
		for( final String notifClass : mEmittedTypes.keySet() )
		{
			final Set<String>	types		= mEmittedTypes.get( notifClass );
				
			final MBeanNotificationInfo	info	= new MBeanNotificationInfo(
				GSetUtil.toStringArray( types ), notifClass, "" );
			
			dynamicInfos.add( info );
		}
		
		final MBeanNotificationInfo[]	dynamicInfosArray	= (MBeanNotificationInfo[])
			dynamicInfos.toArray( new MBeanNotificationInfo[ dynamicInfos.size() ] );
		
		// now merge what we've found with super's types
		
		final MBeanNotificationInfo[]	allInfos	=
			JMXUtil.mergeMBeanNotificationInfos( superTypes, dynamicInfosArray );
		
		return allInfos;
	}
	
	
	/** 
		Cumulatively update our Map of Notification classes and the types corresponding
		to each class. A few of the standard ones are:

<code>
		javax.management.AttributeChangeNotification =>
			{ AttributeChangeNotification.ATTRIBUTE_CHANGE }
			
		javax.management.MBeanServerNotification =>
			{	MBeanServerNotification.REGISTRATION_NOTIFICATION,
				MBeanServerNotification.UNREGISTRATION_NOTIFICATION }
		
		Various others are likely to be just generic Notification:
		javax.management.Notification =>
			{
				x.y.z,
				a.b.c,
				...
			}
</code>
	 */
		private void
	cumulateTypes( final Notification notif )
	{
		final String notifClass	= notif.getClass().getName();
		final String type		= notif.getType();
		
		if ( ! mEmittedTypes.containsKey( notifClass ) )
		{
			final Set<String>	types	= GSetUtil.newStringSet( type );
			mEmittedTypes.put( notifClass, types );
		}
		else
		{
			final Set<String>	types	= mEmittedTypes.get( notifClass );
			if ( ! types.contains( type ) )
			{
				types.add( type );
			}
		}
	}

	/**
		Note that this method may be used to test the functionality of this service
		by asking it to emit any desired Notification.
		<p>
		Note that this method is likely to be called from many different threads.
	 */
		public void
	emitNotification( final Notification notif )
	{
		cumulateTypes( notif );
		
		if ( getListenerCount() != 0 )
		{
			sendNotification( notif );
		}
	}
}