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MessageManager Class Referencefinal

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

#include <juce_MessageManager.h>

Classes

class  Lock
 A lock you can use to lock the message manager. More...
 
class  MessageBase
 Internal class used as the base class for all message objects. More...
 

Public Member Functions

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

Static Public Member Functions

static MessageManagergetInstance ()
 Returns the global instance of the MessageManager.
 
static MessageManagergetInstanceWithoutCreating () noexcept
 Returns the global instance of the MessageManager, or nullptr if it doesn't exist.
 
static void deleteInstance ()
 Deletes the global MessageManager instance.
 
static bool callAsync (std::function< void()> functionToCall)
 Asynchronously invokes a function or C++11 lambda on the message thread.
 
static bool existsAndIsLockedByCurrentThread () noexcept
 Returns true if there's an instance of the MessageManager, and if the current thread has the lock on it.
 
static bool existsAndIsCurrentThread () noexcept
 Returns true if there's an instance of the MessageManager, and if the current thread is running it.
 
static void broadcastMessage (const String &messageText)
 Sends a message to all other JUCE applications that are running.
 

Detailed Description

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

See also
Message, CallbackMessage, MessageManagerLock, JUCEApplication, JUCEApplicationBase

Member Function Documentation

◆ getInstance()

static MessageManager * MessageManager::getInstance ( )
static

Returns the global instance of the MessageManager.

◆ getInstanceWithoutCreating()

static MessageManager * MessageManager::getInstanceWithoutCreating ( )
staticnoexcept

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

◆ deleteInstance()

static void MessageManager::deleteInstance ( )
static

Deletes the global MessageManager instance.

Does nothing if no instance had been created.

◆ 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

◆ 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

◆ hasStopMessageBeenSent()

bool MessageManager::hasStopMessageBeenSent ( ) const
noexcept

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

◆ 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.

◆ callAsync()

static bool MessageManager::callAsync ( std::function< void()> functionToCall)
static

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

Returns
true if the message was successfully posted to the message queue, or false otherwise.

◆ 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
callbackthe function to call - its signature must be
void* myCallbackFunction (void*)
userDataa user-defined pointer that will be passed to the function that gets called
Returns
the value that the callback function returns.
See also
MessageManagerLock

◆ isThisTheMessageThread()

bool MessageManager::isThisTheMessageThread ( ) const
noexcept

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

◆ 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

◆ getCurrentMessageThread()

Thread::ThreadID MessageManager::getCurrentMessageThread ( ) const
noexcept

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

◆ 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.

◆ existsAndIsLockedByCurrentThread()

static bool MessageManager::existsAndIsLockedByCurrentThread ( )
staticnoexcept

Returns true if there's an instance of the MessageManager, and if the current thread has the lock on it.

◆ existsAndIsCurrentThread()

static bool MessageManager::existsAndIsCurrentThread ( )
staticnoexcept

Returns true if there's an instance of the MessageManager, and if the current thread is running it.

◆ broadcastMessage()

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

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

Parameters
messageTextthe string that will be passed to the actionListenerCallback() method of the broadcast listeners in the other app.
See also
registerBroadcastListener, ActionListener

◆ 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

◆ deregisterBroadcastListener()

void MessageManager::deregisterBroadcastListener ( ActionListener * listener)

Deregisters a broadcast listener.


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