/*!
	\file MidiRoster.h
	\ingroup midi2
	\brief Defines the heart of the MIDI Kit: the MIDI Roster.
*/


/*!
	\enum BMidiOp
	\ingroup midi2
	\brief Defines the status codes for MIDI Server notification messages.

	These codes are used when you request notification as in
	BMidiRoster::StartWatching(). Check against these codes to determine what
	is happening. See the StartWatching() method for a more complete
	description of the codes and their meaning.
*/


/*!
	\var B_MIDI_EVENT
	\brief BMessage identifier of MIDI messages.
*/


/*!
	\class BMidiRoster MidiRoster.h
	\ingroup midi2
	\brief Interface to the system-wide Midi Roster.

	BMidiRoster allows you to find available MIDI consumer and producer
	objects. You can locate these objects using the iterative NextEndpoint(),
	NextProducer(), and NextConsumer() methods or by requesting notification
	messages to be sent with StartWatching(). Notification messages may
	contain object IDs which can be resolved using the FindEndpoint(),
	FindProducer(), and FindConsumer() methods.

	The constructor and destructor of BMidiRoster are private, which means
	that you cannot create or delete your own BMidiRoster objects. Every
	application can have only one instance of BMidiRoster, which is
	automatically created the very first time you use a Midi Kit function.
	You can call BMidiRoster's functions like this:
\code
producer = BMidiRoster::FindProducer(someID);
\endcode
Or using the slightly more annoying:
\code
BMidiRoster* roster = BMidiRoster::MidiRoster();
if (roster != NULL)
{
    producer = roster->FindProducer(someID);
}
\endcode
*/


/*!
	\fn BMidiEndpoint* BMidiRoster::NextEndpoint(int32* id)
	\brief Returns the next endpoint from the roster

	The "next endpoint" means: the endpoint with the ID that follows \a id.
	So if you set id to 3, the first possible endpoint it returns is
	endpoint 4. No endpoint can have ID 0, so passing 0 gives you the first
	endpoint. If you pass \c NULL instead of an ID, NextEndpoint() always
	returns \c NULL. When the function returns, it sets \a id to the ID of the
	endpoint that was found. If no more endpoints exist, NextEndpoint()
	returns \c NULL and id is not changed. NextEndpoint() does <b>not</b>
	return locally created endpoints, even if they are Register()'ed.

	Usage example:
\code
int32 id = 0;
BMidiEndpoint* endp;
while ((endp = BMidiRoster::NextEndpoint(&id)) != NULL)
{
    ... do something with endpoint ...
    endp->Release();  // don't forget!
}
\endcode
	Remember that NextEndpoint() bumps the endpoint's reference count, so you
	should always \link BMidiEndpoint::Release() Release() \endlink it when
	you are done.
*/


/*!
	\fn BMidiProducer* BMidiRoster::NextProducer(int32* id)
	\brief Returns the next producer from the roster.

	Like NextEndpoint(), but only returns producer endpoints.

	\sa NextConsumer
	\sa NextEndpoint
*/


/*!
	\fn BMidiConsumer* BMidiRoster::NextConsumer(int32* id)
	\brief Returns the next consumer from the roster.

	Like NextEndpoint(), but only returns consumer endpoints.

	\sa NextProducer
	\sa NextEndpoint
*/


/*!
	\fn BMidiEndpoint* BMidiRoster::FindEndpoint(int32 id,
		bool localOnly = false)
	\brief Returns the endpoint with the specified \a id.

	FindEndpoint() will always find <b>any</b> local endpoints created by this
	application; they do not have to be published with Register() first. If
	localOnly is false, FindEndpoint() also looks at remote endpoints,
	otherwise only local endpoints will be resolved. Returns NULL if no such
	endpoint could be found.

	You should use a dynamic_cast to convert the BMidiEndpoint into a producer
	or consumer:
\code
BMidiEndpoint* endp = ...;
BMidiProducer* prod = NULL;
BMidiConsumer* cons = NULL;
if (endp->IsProducer())
{
    prod = dynamic_cast<BMidiProducer*>(endp);
}
else if (endp->IsConsumer())
{
    cons = dynamic_cast<BMidiConsumer*>(endp);
}
\endcode

	Remember that FindEndpoint() increments the endpoint's reference count,
	so you should always \link BMidiEndpoint::Release() Release() \endlink
	an endpoint when you are done with it:
\code
BMidiEndpoint* endp = BMidiRoster::FindEndpoint(someID);
if (endp != NULL)
{
    ...do stuff with the endpoint...
    endp->Release();
}
\endcode
*/


/*!
	\fn BMidiProducer* BMidiRoster::FindProducer(int32 id,
		bool localOnly = false)
	\brief Finds the producer with the specified \a id.

	Like FindEndpoint(), but only looks for producer endpoints. Returns
	\c NULL if no endpoint with that ID exists, or if that endpoint is not
	a producer.

	\sa FindConsumer
	\sa FindEndpoint
*/


/*!
	\fn BMidiConsumer* BMidiRoster::FindConsumer(int32 id,
		bool localOnly = false)
	\brief Finds the consumer with the specified \a id.

	Like FindEndpoint(), but only looks for consumer endpoints. Returns
	\c NULL if no endpoint with that ID exists, or if that endpoint is not
	a consumer.

	\sa FindProducer
	\sa FindEndpoint
*/


/*!
	\fn void BMidiRoster::StartWatching(const BMessenger* msngr)
	\brief Start receiving notifications from the Midi Roster

	When you start watching, BMidiRoster sends you notifications for all
	currently \b published \c remote endpoints, and all the current
	connections between them. (At this point, BMidiRoster does not let you
	know about connections between unpublished endpoints, nor does it tell
	you anything about your local endpoints, even though they may be
	published.)

	Thereafter, you'll receive notifications any time something important
	happens to an object. The application that performs these operations is
	itself not notified. The assumption here is that you already know about
	these changes, because you are the one that is performing them.

	The notifications are BMessages with code B_MIDI_EVENT. You specify the
	BMessenger that will be used to send these messages. Each message contains
	a field called be:op that describes the type of notification.

	The "registered" and "unregistered" notifications are sent when a remote
	endpoint Register()'s or Unregister()'s, respectively. You don't receive
	these notifications when you register or unregister your local endpoints,
	but the other apps will.

	<table border="1">
		<tr>
			<td>be:op</td>
			<td>int32</td>
			<td>\c B_MIDI_REGISTERED</td>
		</tr>
		<tr>
			<td>be:id</td>
			<td>int32</td>
			<td>id of the endpoint</td>
		</tr>
		<tr>
			<td>be:type</td>
			<td>string</td>
			<td>"producer" or "consumer"</td>
		</tr>
	</table>
	<table border="1">
		<tr>
			<td>be:op</td>
			<td>int32</td>
			<td>\c B_MIDI_UNREGISTERED</td>
		</tr>
		<tr>
			<td>be:id</td>
			<td>int32</td>
			<td>id of the endpoint</td>
		</tr>
		<tr>
			<td>be:type</td>
			<td>string</td>
			<td>"producer" or "consumer"</td>
		</tr>
	</table>

	The "connected" and "disconnected" notifications are sent when a consumer
	\link BMidiProducer::Connect() Connect()\endlink's to a producer, or when
	they \link BMidiProducer::Disconnect() Disconnect() \endlink. You will
	receive these notifications when \b any two endpoints connect or
	disconnect, even if they are not published. (The purpose of which is
	debatable.) You won't receive the notifications if you are the one making
	the connection, even if both endpoints are remote. You \b will be notified
	when another app connects one of your published endpoints.
	<table border="1">
		<tr>
			<td>be:op</td>
			<td>\c int32</td>
			<td>\c B_MIDI_CONNECTED</td>
		</tr>
		<tr>
			<td>be:producer</td>
			<td>\c int32</td>
			<td>id of the connector</td>
		</tr>
		<tr>
			<td>be:consumer</td>
			<td>\c int32</td>
			<td>id of the connectee</td>
		</tr>
	</table>

	<table border="1">
		<tr>
			<td>be:op</td>
			<td>\c int32</td>
			<td>\c B_MIDI_DISCONNECTED</td>
		</tr>
		<tr>
			<td>be:producer</td>
			<td>\c int32</td>
			<td>id of the connector</td>
		</tr>
		<tr>
			<td>be:consumer</td>
			<td>int32</td>
			<td>id of the connectee</td>
		</tr>
	</table>

	the following notifications are sent when an endpoint's attributes are
	changed. you receive these notifications only if another application is
	changing one of its published endpoints.

	<table border="1">
		<tr>
			<td>be:op</td>
			<td>\c int32</td>
			<td>\c B_MIDI_CHANGED_NAME</td>
		</tr>
		<tr>
			<td>be:id</td>
			<td>\c int32</td>
			<td>id of the endpoint</td>
		</tr>
		<tr>
			<td>be:type</td>
			<td>string</td>
			<td>"producer" or "consumer"</td>
		</tr>
		<tr>
			<td>be:name</td>
			<td>string</td>
			<td>the endpoint's new name</td>
		</tr>
	</table>

	<table border="1">
		<tr>
			<td>be:op</td>
			<td>\c int32</td>
			<td>\c B_MIDI_CHANGED_LATENCY</td>
		</tr>
		<tr>
			<td>be:id</td>
			<td>\c int32</td>
			<td>id of the endpoint</td>
		</tr>
		<tr>
			<td>be:type</td>
			<td>string</td>
			<td>"producer" or "consumer"</td>
		</tr>
		<tr>
			<td>be:latency</td>
			<td>int64</td>
			<td>the new latency (microseconds)</td>
		</tr>
	</table>

	<table border="1">
		<tr>
			<td>be:op</td>
			<td>int32</td>
			<td>\c B_MIDI_CHANGED_PROPERTIES</td>
		</tr>
		<tr>
			<td>be:id</td>
			<td>\c int32</td>
			<td>id of the endpoint</td>
		</tr>
		<tr>
			<td>be:type</td>
			<td>string</td>
			<td>"producer" or "consumer"</td>
		</tr>
		<tr>
			<td>be:properties</td>
			<td>bmessage</td>
			<td>the new properties</td>
		</tr>
	</table>

	Typical usage example:

\code
void MyView::AttachedToWindow()
{
    BMessenger msgr(this);
    BMidiRoster::StartWatching(&msgr);
}
void MyView::MessageReceived(BMessage* msg)
{
    switch (msg->what)
    {
        case B_MIDI_EVENT:
            HandleMidiEvent(msg);
            break;
        default:
            super::MessageReceived(msg);
            break;
    }
}
\endcode

	For the possible midi options, see #BMidiOp
*/


/*!
	\fn void BMidiRoster::StopWatching()
	\brief Stop receiving notifications from the Midi Roster.

	\sa StartWatching()
*/


/*!
	\fn status_t BMidiRoster::Register(BMidiEndpoint* object)
	\brief Publishes an endpoint to other applications.

	Calls BMidiEndpoint's \link BMidiEndpoint::Register() Register() \endlink
	method to publish an endpoint, which makes it visible to other
	applications.
*/


/*!
	\fn status_t BMidiRoster::Unregister(BMidiEndpoint* object)
	\brief Hides an endpoint from other applications.

	Calls BMidiEndpoint's
	\link BMidiEndpoint::Unregister() Unregister() \endlink method to hide
	a previously published endpoint from other applications.
*/


/*!
	\fn BMidiRoster* BMidiRoster::MidiRoster()
	\brief Returns a pointer to the only instance of BMidiRoster.

	There is no real reason use this function, since all BMidiRoster's public
	function are static.
*/
