/*! \file MidiRoster.h \ingroup midi2 \ingroup libbe \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 \ingroup libmidi2 \ingroup libbe \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 not 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 any 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(endp); } else if (endp->IsConsumer()) { cons = dynamic_cast(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.
be:op int32 \c B_MIDI_REGISTERED
be:id int32 id of the endpoint
be:type string "producer" or "consumer"
be:op int32 \c B_MIDI_UNREGISTERED
be:id int32 id of the endpoint
be:type string "producer" or "consumer"
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.
be:op \c int32 \c B_MIDI_CONNECTED
be:producer \c int32 id of the connector
be:consumer \c int32 id of the connectee
be:op \c int32 \c B_MIDI_DISCONNECTED
be:producer \c int32 id of the connector
be:consumer int32 id of the connectee
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.
be:op \c int32 \c B_MIDI_CHANGED_NAME
be:id \c int32 id of the endpoint
be:type string "producer" or "consumer"
be:name string the endpoint's new name
be:op \c int32 \c B_MIDI_CHANGED_LATENCY
be:id \c int32 id of the endpoint
be:type string "producer" or "consumer"
be:latency int64 the new latency (microseconds)
be:op int32 \c B_MIDI_CHANGED_PROPERTIES
be:id \c int32 id of the endpoint
be:type string "producer" or "consumer"
be:properties bmessage the new properties
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. */