MessageManager Class Reference

This class is in charge of the application's event-dispatch loop. More...

#include <juce_MessageManager.h>

Collaboration diagram for MessageManager:

Classes
struct	AsyncCallInvoker
class	MessageBase
	Internal class used as the base class for all message objects. More...

Public Member Functions
void *	callFunctionOnMessageThread (MessageCallbackFunction *callback, void *userData)
	Calls a function using the message-thread. More...
bool	currentThreadHasLockedMessageManager () const noexcept
	Returns true if the caller thread has currently got the message manager locked. More...
void	deregisterBroadcastListener (ActionListener *listener)
	Deregisters a broadcast listener. More...
Thread::ThreadID	getCurrentMessageThread () const noexcept
	Returns the ID of the current message thread, as set by setCurrentThreadAsMessageThread(). More...
bool	hasStopMessageBeenSent () const noexcept
	Returns true if the stopDispatchLoop() method has been called. More...
bool	isThisTheMessageThread () const noexcept
	Returns true if the caller-thread is the message thread. More...
void	registerBroadcastListener (ActionListener *listener)
	Registers a listener to get told about broadcast messages. More...
void	runDispatchLoop ()
	Runs the event dispatch loop until a stop message is posted. More...
bool	runDispatchLoopUntil (int millisecondsToRunFor)
	Synchronously dispatches messages until a given time has elapsed. More...
void	setCurrentThreadAsMessageThread ()
	Called to tell the manager that the current thread is the one that's running the dispatch loop. More...
void	stopDispatchLoop ()
	Sends a signal that the dispatch loop should terminate. More...

Static Public Member Functions
static void	broadcastMessage (const String &messageText)
	Sends a message to all other JUCE applications that are running. More...
template<typename FunctionType >
static void	callAsync (FunctionType functionToCall)
	Asynchronously invokes a function or C++11 lambda on the message thread. More...
static void	deleteInstance ()
	Deletes the global MessageManager instance. More...
static MessageManager *	getInstance ()
	Returns the global instance of the MessageManager. More...
static MessageManager *	getInstanceWithoutCreating () noexcept
	Returns the global instance of the MessageManager, or nullptr if it doesn't exist. More...

Private Member Functions
	MessageManager () noexcept

Static Private Member Functions
static bool	dispatchNextMessageOnSystemQueue (bool returnIfNoPendingMessages)
static void	doPlatformSpecificInitialisation ()
static void	doPlatformSpecificShutdown ()
static void *	exitModalLoopCallback (void *)
static bool	postMessageToSystemQueue (MessageBase *)

Private Attributes
ScopedPointer< ActionBroadcaster >	broadcaster
CriticalSection	lockingLock
Thread::ThreadID	messageThreadId
bool	quitMessagePosted = false
bool	quitMessageReceived = false
Thread::ThreadID volatile	threadWithLock = {}

Static Private Attributes
static MessageManager *	instance

Friends
class	MessageBase
class	MessageManagerLock
class	QuitMessage

Detailed Description

This class is in charge of the application's event-dispatch loop.

See also

Message, CallbackMessage, MessageManagerLock, JUCEApplication, JUCEApplicationBase

Constructor & Destructor Documentation

MessageManager()

MessageManager::MessageManager ( )

privatenoexcept

Member Function Documentation

broadcastMessage()

static void MessageManager::broadcastMessage ( const String &  messageText )

static

Sends a message to all other JUCE applications that are running.

Parameters

messageText

the string that will be passed to the actionListenerCallback() method of the broadcast listeners in the other app.

See also

registerBroadcastListener, ActionListener

callAsync()

template<typename FunctionType >

static void MessageManager::callAsync ( FunctionType  functionToCall )

inlinestatic

Asynchronously invokes a function or C++11 lambda on the message thread.

callFunctionOnMessageThread()

void* MessageManager::callFunctionOnMessageThread	(	MessageCallbackFunction *	callback,
		void *	userData
	)

Calls a function using the message-thread.

This can be used by any thread to cause this function to be called-back by the message thread. If it's the message-thread that's calling this method, then the function will just be called; if another thread is calling, a message will be posted to the queue, and this method will block until that message is delivered, the function is called, and the result is returned.

Be careful not to cause any deadlocks with this! It's easy to do - e.g. if the caller thread has a critical section locked, which an unrelated message callback then tries to lock before the message thread gets round to processing this callback.

Parameters

callback	the function to call - its signature must be void* myCallbackFunction (void*)
userData	a user-defined pointer that will be passed to the function that gets called

Returns

the value that the callback function returns.

See also

MessageManagerLock

currentThreadHasLockedMessageManager()

bool MessageManager::currentThreadHasLockedMessageManager ( ) const

noexcept

Returns true if the caller thread has currently got the message manager locked.

see the MessageManagerLock class for more info about this.

This will be true if the caller is the message thread, because that automatically gains a lock while a message is being dispatched.

deleteInstance()

static void MessageManager::deleteInstance ( )

static

Deletes the global MessageManager instance.

Does nothing if no instance had been created.

deregisterBroadcastListener()

void MessageManager::deregisterBroadcastListener

(

ActionListener *

listener

)

Deregisters a broadcast listener.

dispatchNextMessageOnSystemQueue()

static bool MessageManager::dispatchNextMessageOnSystemQueue ( bool  returnIfNoPendingMessages )

staticprivate

doPlatformSpecificInitialisation()

static void MessageManager::doPlatformSpecificInitialisation ( )

staticprivate

doPlatformSpecificShutdown()

static void MessageManager::doPlatformSpecificShutdown ( )

staticprivate

exitModalLoopCallback()

static void* MessageManager::exitModalLoopCallback ( void *  )

staticprivate

getCurrentMessageThread()

Thread::ThreadID MessageManager::getCurrentMessageThread ( ) const

inlinenoexcept

Returns the ID of the current message thread, as set by setCurrentThreadAsMessageThread().

(Best to ignore this method unless you really know what you're doing..)

See also

setCurrentThreadAsMessageThread

getInstance()

static MessageManager* MessageManager::getInstance ( )

static

Returns the global instance of the MessageManager.

Referenced by VideoComponent::Pimpl::DirectShowContext::loadFile().

getInstanceWithoutCreating()

static MessageManager* MessageManager::getInstanceWithoutCreating ( )

staticnoexcept

Returns the global instance of the MessageManager, or nullptr if it doesn't exist.

hasStopMessageBeenSent()

bool MessageManager::hasStopMessageBeenSent ( ) const

inlinenoexcept

Returns true if the stopDispatchLoop() method has been called.

isThisTheMessageThread()

bool MessageManager::isThisTheMessageThread ( ) const

noexcept

Returns true if the caller-thread is the message thread.

postMessageToSystemQueue()

static bool MessageManager::postMessageToSystemQueue ( MessageBase *  )

staticprivate

registerBroadcastListener()

void MessageManager::registerBroadcastListener

(

ActionListener *

listener

)

Registers a listener to get told about broadcast messages.

The actionListenerCallback() callback's string parameter is the message passed into broadcastMessage().

See also

broadcastMessage

runDispatchLoop()

void MessageManager::runDispatchLoop

(

)

Runs the event dispatch loop until a stop message is posted.

This method is only intended to be run by the application's startup routine, as it blocks, and will only return after the stopDispatchLoop() method has been used.

See also

stopDispatchLoop

runDispatchLoopUntil()

bool MessageManager::runDispatchLoopUntil

(

int

millisecondsToRunFor

)

Synchronously dispatches messages until a given time has elapsed.

Returns false if a quit message has been posted by a call to stopDispatchLoop(), otherwise returns true.

Referenced by VideoComponent::Pimpl::DirectShowContext::loadFile().

setCurrentThreadAsMessageThread()

void MessageManager::setCurrentThreadAsMessageThread

(

)

Called to tell the manager that the current thread is the one that's running the dispatch loop.

(Best to ignore this method unless you really know what you're doing..)

See also

getCurrentMessageThread

stopDispatchLoop()

void MessageManager::stopDispatchLoop

(

)

Sends a signal that the dispatch loop should terminate.

After this is called, the runDispatchLoop() or runDispatchLoopUntil() methods will be interrupted and will return.

See also

runDispatchLoop

Friends And Related Function Documentation

MessageBase

friend class MessageBase

friend

MessageManagerLock

friend class MessageManagerLock

friend

QuitMessage

friend class QuitMessage

friend

Member Data Documentation

broadcaster

ScopedPointer<ActionBroadcaster> MessageManager::broadcaster

private

instance

MessageManager* MessageManager::instance

staticprivate

lockingLock

CriticalSection MessageManager::lockingLock

private

messageThreadId

Thread::ThreadID MessageManager::messageThreadId

private

quitMessagePosted

bool MessageManager::quitMessagePosted = false

private

quitMessageReceived

bool MessageManager::quitMessageReceived = false

private

threadWithLock

Thread::ThreadID volatile MessageManager::threadWithLock = {}

private

---

The documentation for this class was generated from the following file:

• juce_MessageManager.h