JBroadcaster Class Reference

#include <JBroadcaster.h>

Inheritance diagram for JBroadcaster:

Classes
struct	ClearPointer
class	Message

Public Member Functions
	JBroadcaster ()
virtual	~JBroadcaster ()
JBroadcaster &	operator= (const JBroadcaster &source)
bool	HasSenders () const
JSize	GetSenderCount () const
bool	HasRecipients () const
JSize	GetRecipientCount () const
virtual JString	ToString () const
template<class T >
void	ListenTo (const JBroadcaster *sender, const std::function< void(const T &)> &f)

Protected Member Functions
	JBroadcaster (const JBroadcaster &source)
void	ListenTo (const JBroadcaster *sender)
void	StopListening (const JBroadcaster *sender)
void	ClearWhenGoingAway (const JBroadcaster *sender, void *pointerToMember)
void	StopListening (const JBroadcaster *sender, const std::type_info &messageType)
template<class T >
void	Send (JBroadcaster *recipient, const T &message)
template<class T >
void	Broadcast (const T &message)
virtual void	Receive (JBroadcaster *sender, const Message &message)
void	SendWithFeedback (JBroadcaster *recipient, Message *message)
void	BroadcastWithFeedback (Message *message)
virtual void	ReceiveWithFeedback (JBroadcaster *sender, Message *message)
virtual void	ReceiveGoingAway (JBroadcaster *sender)

Detailed Description

Mixin class to allow objects to send messages to each other.  A JBroadcaster
maintains a list of objects that send it messages (senders) and a list
of objects to which it sends messages (recipients).

To send a message, call Broadcast().  The Receive() method is then called
for each recipient that called ListenTo(obj).  For every recipient that
called ListenTo(obj,fn), the given function will be invoked.

    ListenTo(obj,fn) should only be used in leaf classes.  Base classes
    should use ListenTo(obj) in case derived classes need to intercept
    messages in Receive().

To send a message that requires feedback, call BroadcastWithFeedback().
The ReceiveWithFeedback() method is then called for each recipient.

To listen for the death of a sender, override ReceiveGoingAway().
    Be sure to read the warnings associated with using this function!

Because the overhead is so low if there is nobody to broadcast to or
nobody to listen to, there is no point in making a separate JListener class.

    Since this is a mixin class, all classes that wish to inherit from it
    must use "virtual public" inheritance.

Constructor & Destructor Documentation

JBroadcaster() [1/2]

JBroadcaster::JBroadcaster

(

)

~JBroadcaster()

JBroadcaster::~JBroadcaster ( )

virtual

Close all connections.

JBroadcaster() [2/2]

JBroadcaster::JBroadcaster ( const JBroadcaster &  source )

protected

Don't copy the connections. We want this to be identical to the default constructor so nobody has to worry about calling us. (Otherwise, they would because we are linked in via virtual inheritance.)

Member Function Documentation

Broadcast()

template<class T >

void JBroadcaster::Broadcast ( const T &  message )

inlineprotected

Send the given message to all recipients. It is the responsibility of derived classes to implement a set of useful messages. Every message must be derived from JBroadcaster::Message and should contain all the information necessary to process the message.

By inlining this part of the function, we avoid the overhead of a function call unless somebody is actually listening.

BroadcastWithFeedback()

void JBroadcaster::BroadcastWithFeedback ( Message *  message )

inlineprotected

Send the given message to all recipients and expect a reply. The reply is message dependent and therefore stored in the message, so we simply send the message as a non-const object and let the receiver who understands the message deal with it.

By inlining this part of the function, we avoid the overhead of a function call unless somebody is actually listening.

ClearWhenGoingAway()

void JBroadcaster::ClearWhenGoingAway ( const JBroadcaster *  csender, void *  pointerToMember  )

protected

Register an object that needs to be forgotten when it is deleted.

GetRecipientCount()

JSize JBroadcaster::GetRecipientCount

(

)

const

GetSenderCount()

JSize JBroadcaster::GetSenderCount

(

)

const

HasRecipients()

bool JBroadcaster::HasRecipients

(

)

const

HasSenders()

bool JBroadcaster::HasSenders

(

)

const

ListenTo() [1/2]

void JBroadcaster::ListenTo ( const JBroadcaster *  csender )

protected

Open a connection by adding the given object to this object's sender list, and adding this object to the given object's recipient list.

If the connection already exists, then we do nothing.

ListenTo() [2/2]

template<class T >

void JBroadcaster::ListenTo	(	const JBroadcaster *	csender,
		const std::function< void(const T &)> &	f
	)

Open a connection by adding the given object to this object's sender list, and adding this object & function to the given object's recipient list.

If the connection already exists, then we replace the previous function.

NOTE: This cannot be used if you intend to use ReceiveWithFeedback().

operator=()

JBroadcaster & JBroadcaster::operator=

(

const JBroadcaster &

source

)

Don't copy the connections.

Receive()

void JBroadcaster::Receive ( JBroadcaster *  sender, const Message &  message  )

protectedvirtual

Process the given message from the given sender. This function is not pure virtual because not all classes will want to implement it.

Reimplemented in JAuxTableData< T >, JAuxTableData< bool >, JAuxTableData< JFontStyle >, JAliasArray< T >, JAliasArray< JString * >, JBroadcastSnooper, JBroadcastTester, JContainer, JFloatBufferTableData, JMemoryManager, JMMMonitor, JNamedTreeList, JSimpleProcess, JTable, JTableSelection, JTableSelectionIterator, JTextEditor, JTreeList, JTreeNode, JXCardFile, JXCheckboxGroup, JXChooseColorDialog, JXChooseFileDialog, JXChooseMonoFont, JXChoosePathDialog, JXColHeaderWidget, JXColorWheel, JXCSFDialogBase, JXDirTable, JXDisplayMenu, JXDockWidget, JXDockWindowTask, JXDocumentMenu, JXEPSPrintSetupDialog, JXFileListTable, JXFileNameDisplay, JXFontNameMenu, JXFontSizeMenu, JXFSInputBase, JXHistoryMenuBase, JXImageMenuTable, JXMenu, JXModalDialogDirector, JXNamedTreeListWidget, JXPGMessageDirector, JXProgressDisplay, JXPSPrintSetupDialog, JXPTPageSetupDialog, JXPTPrintSetupDialog, JXRowHeaderWidget, JXSaveFileDialog, JXScrollableWidget, JXSearchTextDialog, JXSharedPrefObject, JXSliderBase, JXSpellCheckerDialog, JXStringCompletionMenu, JXStringList, JXStyleMenu, JXTable, JXTEBase, JXTextEditor, JXTextMenuTable, JXToolBar, JXTreeListWidget, and JXWDMenu.

ReceiveGoingAway()

void JBroadcaster::ReceiveGoingAway ( JBroadcaster *  sender )

protectedvirtual

The given sender has been deleted.

Warning: Since this function may be called from within a -chain- of destructors, it is not usually safe to do anything inside this function other than directly changing instance variables (e.g. setting pointers to nullptr).

This function is not pure virtual because not all classes will want to implement it.

Reimplemented in JAliasArray< T >, JAliasArray< JString * >, JBroadcastSnooper, JBroadcastTester, JTableSelectionIterator, JTextEditor, JXCheckboxGroup, JXDNDManager, JXDockWidget, JXSelectionData, and JXStringList.

ReceiveWithFeedback()

void JBroadcaster::ReceiveWithFeedback ( JBroadcaster *  sender, Message *  message  )

protectedvirtual

Process the given message from the given sender and provide feedback via the message as appropriate. This function is not pure virtual because not all classes will want to implement it.

Reimplemented in JXApplication, JXDNDManager, JXSearchTextDialog, and JXSelectionManager.

Send()

template<class T >

void JBroadcaster::Send ( JBroadcaster *  recipient, const T &  message  )

protected

Send the given message to the specified recipient. It is the responsibility of derived classes to implement a set of useful messages. Every message must be derived from JBroadcaster::Message and should contain all the information necessary to process the message.

This function allows messages to be sent to an object in a way that is safe but that does not require the C++ type safety mechanism of dynamic_cast. Essentially, this feature is equivalent to the object methods provided by Objective C.

SendWithFeedback()

void JBroadcaster::SendWithFeedback ( JBroadcaster *  recipient, Message *  message  )

protected

Send the given message to the specified recipients. It is the responsibility of derived classes to implement a set of useful messages. Every message must be derived from JBroadcaster::Message and should contain all the information necessary to process the message.

This function allows messages to be sent to an object in a way that is safe but that does not require the C++ type safety mechanism of dynamic_cast. Essentially, this feature is equivalent to the object methods provided by Objective C.

StopListening() [1/2]

void JBroadcaster::StopListening ( const JBroadcaster *  csender )

protected

Close a connection by removing the given object from this object's sender list, and removing this object from the given objects's recipient list.

StopListening() [2/2]

void JBroadcaster::StopListening ( const JBroadcaster *  csender, const std::type_info &  messageType  )

protected

Close a connection by removing the given object from this object's sender list, and removing this object from the given objects's recipient list.

ToString()

JString JBroadcaster::ToString ( ) const

virtual

Reimplemented in JCollection, JXFTCCell, JXInputField, JXStaticText, JXTextButton, JXTextCheckbox, JXTextRadioButton, and JXWidget.

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

• libjcore/code/JBroadcaster.h
• libjcore/code/JBroadcaster.cpp
• libjcore/code/JBroadcaster.tmpl